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purification and characterization of precipitating antigens from theileria parva.precipitating antigens from theileria parva have been partially purified. two antigens from each of the schizont and piroplasm stages of the parasite were identified; the major antigens from the two stages shared the same specificity. the antigens showed considerable molecular heterogeneity, almost certainly a result of the preparative method, and they always contained large amounts of dna. the piroplasm antigens were of parasite nuclear origin and the schizont antigens were probably of the same ...197770504
histopathologic and electron microscopic studies of cutaneous lesions in calves with experimentally induced east coast fever (theileriosis).skin lesions of bovine east coast fever were examined by light and electron microscopy at 120 hours after attachment of rhipicephalus appendiculatus ticks infected with theileria parva. lesions included epidermal ulcer, hemorrhage, edema, necrosis, and inflammatory cell infiltration by mostly polymorphonuclear and mononuclear (lymphoid) cells. the trophozoite state of t parva was observed in a parasitophorous vacuole and feeding on neutrophil granules. schizonts, some in budding process, and mer ...197898077
induction of infective stages of theileria parva by exposure of host ticks to high temperature.it was demonstrated that theileria parva parasites infective to cattle could be induced by exposure of infected adult rhipicephalus appendiculatus ticks to 37 degrees c. the production of the sporozoites of t parva was not as efficient as by feeding ticks on rabbits.1979119344
cell-mediated immunity to theileria-transformed cell lines.in east and central africa the protozoan parasite theileria parva causes a disease of cattle called east coast fever (ecf). in kenya alone between 60,000 and 85,000 cattle die from ecf every year. infected animals can recover from ecf either naturally or after treatment with tetracyclines or menoctone and are subsequently able to resist challenge with the homologous strain of parasite. that this acquired resistance is due to cell-mediated rather than humoral immunity has been suspected but never ...1979162151
attempts to produce theileria parva-infected mouse cells using cell fusion techniques.ehrlich ascites tumour (eat) cells were fused with theileria parva-infected bovine lymphoid (c2) cells using inactivated sendai virus. a variety of techniques were employed to try and increase fusion percentage and harvest of heterokaryons. there was no evidence that pre-exposure of c2 cells to sendai virus or phytohaemagglutinin improved fusion percentage, but the percentage was higher when 10(8) c2 cells were fused with 10(7) eat cells, as compared with a ratio of 10(7) c2: 10(6) eat. an incre ...1976184506
studies on theileriidae (sporozoa) in tanzania. vi. second field trial on immunization against cattle theileriosis.nine cattle, immunized by an infection and treatment method with 3 strains of theileria parva (muguga, kiambu 5 and serengeti transformed) and nine controls, were exposed to natural tick infestation in tanzania. all controls contracted fatal east coast fever within 2 months of exposure. all immunized animals survived the period of exposure (over 2 months), but later one died of ecf, one of heart-water, one of an undetermined cause (not a theileriosis), and one disappeared from the herd. the 5 re ...1977324053
detection of antibodies in trypanosome-infected cattle by means of a microplate enzyme-linked immunosorbent assay.a micromodification of the enzyme-linked immunosorbent assay (elisa) was evaluated for its potential application in the immunodiagonsis of bovine trypanosomiasis. serum samples from infected and non-infected zebu cattle and samples from friesian cattle with experimental infections were exmained for the presence of trypanosomal antibodies. there were significant differences between the microelisa values obtained with samples from infected and non-infected cattle. during the course of infection mi ...1977333677
studies on theileriidae (sporozoa) in tanzania. viii. experiments with african buffalo (syncerus caffer).it has been found that african buffalo may remain infective carriers of theileria parva lawrencei for at least 5 years. this infection is now known to exist in buffalo in 3 sites in northern tanzania. it was shown that buffalo can be infected with haematoxenus veliferus and theileria mutans of cattle and retransmission of these parasites from buffalo to cattle was successful. the species of haematoxemus reported in wild buffalo in central and east africa is likely to be h. veliferus, while the p ...1977410128
east coast fever immunisation trials in uganda: field exposure of zebu cattle immunized with three isolates of theileria parva. 1977413226
serum transaminase activities in the bovine experimentally infected with east coast fever (theileria parva infection). 1979548138
experimental therapy of theileriosis.a tissue culture method was used to screen compounds for activity against theileria parva, and demonstrated that the hydroxy-alkylated naphthoquinones, 'menoctone' and 993c were highly active, with ed50 values around 0,005 mg/l. when injected into cattle artificially infected the t. parva, menoctone cured all of 7 cattle at a total dosage of 10 mg/kg injected intravenously (i.v.). a further trial showed that injection of menoctone, 10 mg/kg, as a single dose gby the intramuscular (i.m.) route wa ...1979553970
immunization of cattle against theileria parva. 1977596297
theileria parva: significance of leukocytes for infecting cattle. 1978668839
the effect of 3, 6, bis-dimethylaminoacridine on cultured bovine lymphoid cells infected with theileria parva and in cattle experimentally infected with east coast fever. 1975805506
theileria parva: effects of irradiation on a culture of parasitized bovine lymphoid cells. 1975807485
hybrid cells, infected with theileria parva, formed by fusion of hamster and mouse cells with parasitised bovine lymphoid cells.bovine lymphoid cells from a culture line parasitised with theileria parva were fused to mouse heart (mh) and baby hamster kidney (bhk) cells, grown as monolayers, using inactivated sendai virus. the resultant heterokaryons contained macroschizonts of t parva. macroschizonts also occurred in cells that apparently contained only bhk or mh nuclei. parasites underwent varying degrees of development; in some cases microschizonts resulted, and in other cases massive atypical parasite masses were form ...1975809820
simulation in vitro of bovine host cycle of theileria parva. 1976818570
the serological relationship between theileria parva (muguga) and theileria lawrence from rhodesia.thirty-eight sera from cattle from a herd in rhodesia naturally infected with theileria lawrencei were titrated with the indirect immunofluorescent test against schizont antigens of t parva (muguga) and t lawrencei from rhodesia. t lawrencei was found to be indistinguishable from t parva with the test.1977878256
chemotherapy of theileria parva infection. 1976934316
the effect of calf lymph and bovine red blood cells on in vitro cultivation of theileria parva-infected lymphoid cells.calf lymph introduced to cultures of theileria parva-infected lymphoid cells caused a stimulation of both cells and parasites resulting in the formation of rapidly dividing cells and the developmental stages of the parasite. the presence of piroplasms was confirmed when washed bovine red blood corpuscles were added to the culture1976968954
an ultrastructural study of heterokaryons derived from theileria parva-infected bovine lymphoblasts and ehrlich ascites tumour cells.an ultrastructural study was made of sendai virus induced heterokaryons derived from theileria parva-infected lymphoblasts and ehrlich ascites tumour cells. when fusion occurred, parasites were successfully integrated into the cytoplasm of the resulting heterokaryons where they appeared as morphologically normal macroschizonts. homokaryon formation was also noted. this occurred frequently between ehrlich ascites tumour cells and rarely with lymphoblasts. a small proportion of heterokaryons conta ...1976987607
comparative growth of bovine lymphosarcoma cells and lymphoid cells infected with theileria parva in athymic (nude) mice. 19751173457
interactions between chemotherapy and immunity in bovine theileriosis.in bovine theileriosis the use of chemotherapy to control an infection sufficiently long to permit the establishment of a solid protective immune response has been developed as a routine vaccination procedure. infections with theileria parva and t. annulata can be prevented by the administration of carefully controlled numbers of sporozoites simultaneously with a long acting tetracycline and this form of immunization has been widely used for the control of east coast fever in africa with conside ...19921308933
detection of a carrier state in theileria parva-infected cattle by the polymerase chain reaction.two sets of oligonucleotide primers, one derived from a repetitive sequence and the other from the gene encoding a 67 kda sporozoite antigen of theileria parva, were used to amplify parasite dna from the blood of t. parva-infected carrier cattle using the polymerase chain reaction (pcr). pcr amplification products were obtained from 15 carrier cattle infected with one of 4 different t. parva stocks. successful amplifications were performed using dna from 2 cattle infected with t. p. parva pemba ...19921350672
theileria parva: cd4+ helper and cytotoxic t-cell clones react with a schizont-derived antigen associated with the surface of theileria parva-infected lymphocytes.theileria parva is a protozoan parasite which infects and transforms bovine lymphocytes, resulting in a fatal lymphoproliferative disease. there is evidence that immunity to the intralymphocytic schizont stage is mediated by t cells. we have previously reported derivation of cd4+ t-cell clones which recognize parasite-derived antigens presented on the surface of infected cells in conjunction with mhc molecules and partial characterization of the antigens. the present study further evaluated one ...19921353459
studies on theileriidae (sporozoa) in tanzania. v. preliminary experiments on a new method for infecting ticks with theileria parva and theileria mutans.bovine blood with a high parasitaemia of theileria mutans was injected through the cuticle into fully engorged nymphs of amblyomma variegatum which had recently detached from a rabbit. after moulting, they transmitted this parasite to a susceptible calf. rhipicephalus appendiculatus transmitted theileria parva in the same way, but results were negative with a. variegatum and t. parva. this method of infecting ticks appears promising for the isolation of theileria strains from the field, and migh ...19761006800
studies on theileriidae (sporozoa) in tanzania. iv. a field trial on immunization against east coast fever (theileria parva infection of cattle).seven cattle, immunized by an infection and treatment method with 3 strains of theileria parva (muguga, kiambu 5 and serengeti transformed), and five controls were exposed to natural tick infestation in tanzania, at a site where 2 precontrols had previously contracted fatal east coast fever within 3 weeks. all controls became infected with fatal ecf within a month of exposure. one immunized animal survived, two died from a theileria mutans infection and one from a babesia bigemina infection. the ...1976982549
adaptation and possible attenuation of theileria parva-infected cells grown in irradiated mice. 1976815278
the cytotoxic t cell: mhc restriction, strain specificity and role in immunity to theileria parva infection. 19921416743
a clinical trial of buparvaquone in the treatment of east coast fever.a clinical trial was conducted to test buparvaquone (butalex; coopers pitman-moore) in the treatment of east coast fever under field conditions in kenya. data from 229 cases were analysed following treatment with one (69), two (142) or three (18) doses at 2.5 mg/kg. the majority of cattle (95.2 per cent) were exotic (bos taurus) or improved (bos taurus cross bos indicus) and 39.3 per cent were infected with anaplasma marginale. there was an overall recovery rate of 85.6 per cent, with 90.1 per c ...19921441098
the effect of leucocytes from cattle immunized against east coast fever on the migration of bovine lymphoblasts infected with theileria parva. 1975812298
east coast fever: cultivation in vitro of cell-free schizonts and merozoites of theileria parva and their immunogenicity in cattle.cell-free schizonts and merozoites of theileria parva and theileria lawrencei, derived from parasitized lymphoid cell lines, were propagated in vitro using enriched medium. use of radioisotopic markers showed that the bovine cell-independent parasites passed through a limited but marked replication by day 4. if normal bovine rbc were inoculated in vitro with the cell-free merozoites, development of piroplasms in the rbc occurred. electron microscopic studies of the merozoites and piroplasms reve ...1978415644
development of theileria parva (theiler, 1904) in the gut of rhipicephalus appendiculatus (neumann, 1901). 1977415285
studies on theileriidae (sporozoa) in tanzania. vii. additional note on the transmission of theileria parva.rhipicephalus evertsi successfully transmitted fatal east coast fever (theileria parva infection) in one experiment. a second one gave negative results, as did an attempted transmission of t. parva by amblyomma variegatum.1977407682
characterisation of the gene encoding a candidate vaccine antigen of theileria parva sporozoites.we have cloned and characterised the gene encoding the 67-kilodalton stage-specific surface antigen, p67, of theileria parva (muguga) sporozoites. the gene which is present in a single copy, is divided into 2 exons by an intron 29 bp long and is transcribed into mrna of about 2500 nucleotides. the gene is present in all stocks of t. parva and there is a related gene in theileria annulata. the deduced amino acid sequence of 709 residues predicts that p67 is a membrane protein and that it lacks ta ...19921565135
initial studies on the properties of a bovine lymphoid cell culture line infected with theileria parva. 1978154370
theileria parva: purine and pyrimidine metabolism and the action of folate antagonists in parasitized bovine lymphoid cells. 1977138597
standardization of a technique for analysing the frequency of parasite-specific cytotoxic t lymphocyte precursors in cattle immunized with theileria parva.a limiting dilution microculture system was optimized to quantify the frequency of theileria parva-specific cytotoxic t lymphocyte precursors (ctlp) in peripheral blood mononuclear cells (pbmc) from immune cattle. optimal results were obtained with responder cell input levels ranging from 2 x 10(4)/well to 6.25 x 10(2)/well, along with 1-5 x 10(3)/well stimulator cells in standard supplemented rpmi 1640 medium containing 2.5-5% t cell growth factors. thirty-six microtitre wells were established ...19921570170
analysis of theileria parva immunodominant schizont surface antigen by two-dimensional polyacrylamide gel electrophoresis and immunoblotting. 19921584754
artificial infection of the tick rhipicephalus appendiculatus with theileria parva.methods for infecting rhipicephalus appendiculatus ticks with theileria parva by injection and by artificial feeding were confirmed and compared. the injection method proved simpler and at best as effective and suggested improvements are described.1979122269
skin nodules in east coast fever.a skin eruption developed in five calves with advanced experimental east coast fever (ecf) (theileria parva infection). in three cases the eruption was due to intradermal nodules containing numerous theilerial schizonts, in one animal the nodules contained abscesses filled with demodex mites, and in the fifth calf both types of nodules were present. no nodules were seen in 15 other experimental cases of ecf, which generally died or were killed in an earlier stage of the disease. it is postulated ...1979122267
growth of theileria annulata and theileria parva macroschizont-infected bovine cells in immunodeficient mice: effect of irradiation and tumour load on lymphocyte subsets.bovine cells infected with macroschizonts of the protozoan parasites theileria annulata and theileria parva formed solid tumours when injected into irradiated balb/c and irradiated balb/c nude mice. t. annulata tumours grew more vigorously than t. parva tumours, when initiated with similar doses of infected cells in mice exposed to the same doses of gamma-irradiation. in irradiated balb/c mice, tumours of both species of parasites began to regress 2-3 weeks after injection of cells but grew with ...19921644524
the differential diagnosis of the bovine theilerias of southern africa.it is currently thought that the following species or sub-species of theileria occur in cattle in southern africa: theileria parva parva (east coast fever), theileria parva lawrencei (corridor disease), theileria parva bovie (rhodesian theileriosis), theileria mutans proper (transmitted by amblyomma species), so-called theileria mutans (a non-pathogenic species transmitted by rhipicephalus appendiculatus, possibly identical with theileria taurotragi) and theileria velifera. the parasites can be ...1979122000
in vitro studies on the action of menoctone and other compounds on theileria parva and t. annulata.bovine lymphoblastoid cell cultures permanently infected with theileria parva and t. annulata were used in an in vitro screen to test a wide range of compounds for chemotherapeutic activity against these parasites. only two compounds, menoctone and methotrexate, showed significant activity, which has subsequently been confirmed by tests in infected cattle. menoctone was about 100 times more active than methotrexate. mixtures of menoctone and various other other compounds were tested, but showed ...1978104669
antibody-dependent cell-mediated cytotoxicity in cattle: activity against 51cr-labeled chicken erythrocytes coated with protozoal antigens.bovine mononuclear cells in the presence of bovine anti-chicken erythrocyte sera at high dilutions induce release of chromium-51 from labeled chicken erythrocytes. bovine effector cells are capable of recognizing both bovine immunoglobulin g(1) and bovine immunoglobulin g(2); in contrast, human effector cells only recognize immunoglobulin g(1). effector cell activity of bovine mononuclear cells is equally distributed between peripheral blood and spleen. as in other species, thymus and lymph node ...1978103832
production of interferons by bovine and ovine cell lines infected with theileria annulata or theileria parva.three bovine cell lines and four ovine cell lines infected with theileria parva or theileria annulata were examined for the production of interferon (ifn). biologically active ifn was detected in the tissue culture supernatants of four of the cell lines. only one, a bovine cell line infected with t. parva, produced ifn-gamma as measured by specific neutralization with a monoclonal antibody to bovine ifn-gamma. this observation was confirmed by analysing rna from the cell lines on northern blots ...19911712932
rapid quantitative assessment of theileria infection in ticks.a simplified method for methyl green pyronin staining is described for theileria parva and t. annulata in whole salivary glands of rhipicephalus appendiculatus and hyalomma anatolicum subspecies respectively. the stain gives results comparable with feulgen staining and can be used after the ticks have been in cold storage for 3 days. there is considerable variability in the rate and intensity of infection of these ticks with theilerial parasites and it is concluded that the method permits large ...197987045
effect of humoral antibodies on the course of theileria parva infection (east coast fever) of cattle.a study was made of the effects of serum and gamma-globulins from vaccinated cattle (donor cattle) given to cattle (principals) exposed to theileria parva infection (east coast fever (ecf)). the principals were treated with normal serum, with serum containing high antibody titer against t parva (as evaluated by the indirect fluorescent antibody (ifa) technique), or with globulins prepared from normal and from immune serums. for exposure, the principals were inoculated with standardized suspensio ...197547727
electron microscopic studies on the development of kinetes of theileria parva theiler, 1904 in the gut of the vector ticks rhipicephalus appendiculatus neumann, 1901.the development of motile stages, called kinetes, from a stationary stage (regarded as zygote) has been followed in theileria parva by means of electron miscroscopy. this process started after moult of the tick nymphs which had sucked on highly infected calves, i.e. about 20 days after repletion (a.r.) of the ticks. the transformation took place by formation of a growing protrusion (= anlage) into an inner, enlarging vacuole. during this process the limiting membrane of the enlarging vacuole ser ...197828653
cloning and characterization of the casein kinase ii alpha subunit gene from the lymphocyte-transforming intracellular protozoan parasite theileria parva.theileria parva is an obligate intracellular protozoan parasite which is the causative agent of east coast fever, an acute, leukemia-like disease of cattle. the intralymphocytic stage of the parasite induces blastogenesis and clonal expansion of quiescent bovid lymphocytes. experiments in our laboratory have shown a marked increase of casein kinase ii- (ck ii-) like activity in t. parva-transformed lymphocytes. we have also detected ck ii activity in purified t. parva schizonts. to explore the s ...19921378299
exposure of ankole and crossbred cattle to theileriosis in rwanda.susceptible ankole (sanga: bos indicus/bos taurus) and crossbred ankole x jersey (b. taurus) and ankole x sahiwal (b. indicus) cattle derived from a farm in rwanda with no recent history of theileriosis, were infected with theileria parva stocks from rwanda either by feeding infected rhipicephalus appendiculatus ticks on the ears, inoculation of tick derived stabilate or natural exposure to tick challenge. the ankole cattle originated from local stock born and bred in east coast fever (ecf) ende ...19911796523
improved isolation of rinderpest virus in transformed bovine t lymphoblast cell lines.bovine t lymphoblast cell lines transformed by the protozoan theileria parva were compared with bovine kidney (bk) and vero cells for their ability to isolate various strains of rinderpest virus from tissues and infected secretions. all of the strains of rinderpest virus that were tested, including attenuated cell-culture, caprinised and lapinised vaccines, and both mild and virulent pathogenic strains, readily induced syncytial cytopathic effect (cpe) in t lymphoblasts. the cpe could often be d ...19921410806
an unusual repetitive gene family in theileria parva which is stage-specifically transcribed.tpr1 is a repetitive dna element from theileria parva which has previously been shown to be of value in strain characterisation. further characterisation, described here, has shown that tpr1 is present in long tandem arrays. the sequence of 8.1 kb from one end of an array has been determined. the sequence showed that tpr1 is a 1.44-kb element which contains an orf extending from its 5' end to the 3' end. the sequenced region contains 4 large orfs; 2 of these consisted only of tpr1 whilst the thi ...19911840629
immunization against east coast fever (theileria parva infection of cattle) by infection and treatment: chemoprophylaxis with n-pyrrolidinomethyl tetracycline.cattle were immunized against east coast fever by the inoculation of a tick-derived stabilate of theileria parva infective particles and the intramuscular injection, at daily intervals, of n-pyrrolidinomethyl tetracycline at a dose level of 5 mg/kg. four doses of the tetracycline, starting on the day of inoculation of the infective stabilate, minimised the ecf reactions in the cattle during immunization. immunity to homologous t. parva stabilate challenge was demonstrated in 27 out of 27 cattle ...1977910283
[electron microscope studies on developmental stages of theileria parva (theiler, 1904) in the intestine of the tick hyalomma anatolicum excavatum (koch, 1844) (author's transl)].the developmental stages of theileria parva within the intestine of ticks were studied by electron microscopy. on the 2nd-4th day post repletionem (p.r.) the intestine of the ticks contained numerous stages, which were very similar to microgamonts and microgametes of haemosporidia. from these results it seemed likely that gamogony of theileria parva takes place in the intestine of ticks, too. the microgamont-like stages were spear-head-like; they measured about 10.5 mum in length with a maximum ...1976821188
the specific immunoglobulin response in cattle to theileria parva (muguga) infection.cattle were inoculated with dilutions of theileria parva (muguga) stabilate without concurrent antibiotic treatment. the dilutions were selected to induce severe east coast fever infections, which in some cases would lead to death. serum samples were collected and the complement fixation (cf), indirect haemagglutination (iha) and indirect immunofluorescence (ifa) tests were used to detect t. parva serum antibodies. sera were fractionated on sephadex g200 to determine the activities of specific i ...1975804155
heterotransplantation of theileria parva-infected cells to athymic mice. 1975804142
analysis of the reactivity of anti-bovine cd8 monoclonal antibodies with cloned t cell lines and mouse l-cells transfected with bovine cd8.mouse l-cells transfected with bovine cd8 and two theileria parva-infected cloned t cell lines expressing bovine cd8 were used to screen the panel of ten monoclonal antibodies (mabs) submitted to the workshop. eight of the ten mabs reacted with the transfectant and both the cloned t cell lines. however, two mabs cc58 and bat82a did not recognise the transfectant and only reacted with one of the t cell lines. further biochemical studies indicated that the eight mabs react with both homo- and hete ...19911902341
the use of tetracyclines on the chemotherapy of experimental east coast fever (theileria parva infection of cattle).in a series of experiments, groups of cattle, undergoing patent east coast fever (ecf) reactions induced by the inoculation of tick-derived stabilates of theileria parva infective particles, were treated by parenteral administration of 2 tetracyclines. ten cattle were treated with n-pyrrolidinomethyl tetracycline at 15 mg/kg for 5 days, starting on the first day macroschizonts were detected in lymph node biopsy smears. nine of these treated cattle survived ecf reactions induced by an inoculum wh ...1977414390
theileria parva piroplasmosis in mice, and its attempted transmission with rhipicephalus appendiculatus ticks.theileria parva piroplasm infection of mouse erythrocytes was detected, following intraperitoneal inoculation of mice with irradiated cultures of t. parva-infected bovine lymphoid cells. infection could not be transmitted to cattle using rhipicephalus appendiculatus ticks.1977414389
studies on theileriidae (sporozoa) in tanzania. x. a large-scale field trial on immunization against cattle theileriosis.50 cattle immunized by an infection and treatment method with 3 strains of theileria parva (mugaga, kiambu 5 and serengeti transformed), together with 19 controls, were exposed to natural tick infestation in tanzania, in a site where a continuous influx of infected ticks from different regions of the country may be expected to occur. exposure lasted for 2 months, monitoring continued for 3 more weeks after exposure ended. all 19 controls contracted east coast fever and died. 40 of the 50 immuniz ...1977414388
immune cd4+ t cells specific for theileria parva-infected lymphocytes recognize a 24-kilodalton protein.theileria parva is a protozoan parasite that infects and transforms bovine lymphocytes. here we report the partial purification of a t. parva-specific protein from infected lymphocytes that is recognized by cd4+ parasite-specific t-cell clones derived from immune cattle. t. parva-infected lymphocytes were homogenized in dulbecco's phosphate-buffered saline in the presence of protease inhibitors. the antigen was purified from a postmicrosomal supernatant by using a combination of deae-cellulose c ...19921354201
immunisation of cattle against theileriosis in nakuru district of kenya by infection and treatment and the introduction of unconventional tick control.one hundred and one cross european-boran cattle (50 cows and 51 calves), on a farm in nakuru district, kenya, were immunised against theileriosis using theileria parva lawrencei and theileria parva parva stocks from another district of kenya. the stabilates used were t.p.lawrencei (mara iii) used at 10(-1.7) dilution and t.p.parva (kilae) used at 10(-1.0) dilution. the stabilates were combined and inoculated simultaneously with a short-acting formulation of oxytetracycline hydrochloride given in ...19921496782
transformation of theileria parva derived from african buffalo (syncerus caffer) by tick passage in cattle and its use in infection and treatment immunization.a sporozoite stabilate (st. 199) of theileria parva was obtained by feeding nymphal rhipicephalus appendiculatus on an african buffalo (syncerus caffer) and was used to immunize cattle by the infection and treatment method. nymphal ticks were applied to one of the steers 90 days later and it was shown that the resultant adult tick had become infected. using tick/cattle passage, two passage lines of t. parva were established. by the fifth tick/cattle passage, the parasite stocks had changed their ...19921496792
further evaluation of the use of buparvaquone in the infection and treatment method of immunizing cattle against theileria parva derived from african buffalo (syncerus caffer).three experiments were undertaken to determine the efficacy of different doses of buparvaquone in the infection and treatment immunization of cattle against theileria parva derived from african buffalo (syncerus caffer). two of these experiments also compared buparvaquone with standard doses of long- and short-acting formulations of oxytetracycline. in addition, different dilutions of stabilates were used in the experiments. in the first experiment, a 10(-1.0) dilution of stabilate was used to i ...19921496799
immunization with theileria parva parasites from buffaloes results in generation of cytotoxic t cells which recognize antigens common among cells infected with stocks of t. parva parva, t. parva bovis, and t. parva lawrencei.immunity to infection by the protozoan parasite theileria parva in cattle is partially attributable to cytotoxic t cells, which kill lymphocytes infected with the schizont stage of the parasite. here we evaluated five stocks of buffalo-derived t. parva lawrencei parasites and two stocks of cattle-derived t. parva parva parasites for their ability to induce in vivo cytotoxic t cells which can kill lymphocytes infected with a wide variety of strains of t. parva parasites. a group of seven full-sib ...19901699896
a recombinant sporozoite surface antigen of theileria parva induces protection in cattle.at present immunization against theileria parva is by infection with live sporozoites and simultaneous treatment with a long-acting oxytetracycline. this method has major limitations in that live organisms are used and the immunity engendered is parasite stock specific. in an attempt to develop an alternative immunization procedure, the gene encoding p67, a major surface antigen of sporozoites, has been expressed by using the plasmid expression vector pmg1. the gene, which has been characterized ...19921731322
agarose entrapment method for the production of sfii linking library for theileria parva.we have developed a simple method for isolation of sfii linking clones from a eukaryotic genomic dna. the method involves the physical separation of the small proportion of plasmids in a plasmid genomic library that are linearized by sfii digestion, from the bulk of molecules that remain circular, by ordinary electrophoresis through high-percentage gels of seaplaque agarose. following the isolation of linearized molecules, their recircularization, and introduction into escherichia coli, 55% of r ...19911931184
il-2 can enhance the cyclosporin a-mediated inhibition of theileria parva-infected t cell proliferation.the effect of cyclosporin a on the continuous proliferation of theileria parva-infected t cells was tested and compared with its effect on the con a-induced proliferation of bovine lymph node cells. the effect of ril-2 on cyclosporin a-treated cells was also tested. whereas the con a-induced proliferation of bovine lymph node cells was completely inhibited by cyclosporin a, the continuous growth of t. parva-infected cells was only partly inhibited. in both cases the inhibition was accompanied by ...19902104902
the effects of oxytetracycline on theileria parva in vitro.when bovine peripheral blood leucocytes were infected with theileria parva sporozoites, immediate treatment with oxytetracycline (otc) inhibited the development of sporozoites to mature schizonts. the extent of inhibition was dependent on drug concentration and duration of treatment. concentrations of 5 micrograms/ml otc, or higher, for 8 days completely inhibited the establishment of schizonts and their ability to transform host cells. a cytostatic effect on schizont-infected cell lines was fou ...19902107502
cell surface phenotype of two cloned populations of bovine lymphocytes displaying non-specific cytotoxic activity.monoclonal antibodies specific for t cell differentiation antigens were tested on four cloned populations of lymphocytes derived from the peripheral blood mononuclear cells of an animal immunised with theileria parva. the clones were defined functionally in terms of cytotoxic activity, mhc restriction and expression of messenger rna for cd3 and t cell receptor (tcr). two clones contained rna transcripts for cd3, tcr-alpha and beta and were positive for cd2, cd5 and cd6; one of these was a typica ...19911826981
lymphocytes infected with theileria parva require both cell-cell contact and growth factor to proliferate.lymphocytes infected with the intracellular parasite theileria parva proliferate continuously as lymphoblastoid cell lines. we have previously shown that the continuous proliferation of the t. parva-infected (tpi) cell line tpm(803) is mediated in part by an autocrine mechanism (dobbelaere, d. a. e. et al., proc. natl. acad. sci. usa 1988. 85:4730). we now report that continuous proliferation also requires surface stimulation through cell-cell contact. under standard culture conditions this surf ...19911899385
the entry of theileria parva sporozoites into bovine lymphocytes: evidence for mhc class i involvement.we have examined the process of theileria parva sporozoite entry into susceptible bovine lymphocytes and have begun to identify one of the possible molecular interactions involved in the process. the entry process involves a defined series of events and we have used a number of experimental procedures in combination with a method of quantitation to examine various aspects of this process. t. parva sporozoites are nonmotile organisms and the initial sporozoite-lymphocyte interaction is a chance e ...19911901066
a bovine class i major histocompatibility complex molecule plus a theileria parva antigen resembles mouse h-2kd.two bot2+, bot8+ cytotoxic t cell clones were generated from peripheral blood of a steer immunized with the intracellular protozoan parasite theileria parva. both cytotoxic t cell clones appeared to be restricted by the same major histocompatibility complex (mhc) molecule and were specific for the immunizing parasite clone. however, one of the two clones also recognized uninfected mouse cell lines carrying the h-2d haplotype. inhibition of cytotoxicity with monoclonal antibodies specific for pol ...19902125183
development and persistence of cowdria ruminantium specific antibodies following experimental infection of cattle, as detected by the indirect fluorescent antibody test.different breeds of cattle were experimentally infected with palm river, a zimbabwean isolate, or ball-3, a south african isolate of cowdria ruminantium, derived from tissue culture or tick or blood stabilates. c. ruminantium specific antibody responses were detected by an indirect fluorescent antibody test (ifat) using c. ruminantium-infected bovine aortic endothelial (bae) cell cultures as antigen. the first detection of antibodies to c. ruminantium generally coincided with the peak of the feb ...19921441219
effects of gamma interferon, tumor necrosis factor alpha, and interleukin-2 on infection and proliferation of theileria parva-infected bovine lymphoblasts and production of interferon by parasitized cells.theileria parva is a protozoan parasite that infects bovine b cells and alpha beta and gamma delta t cells and transforms them into continually proliferating cells. cd4+ t. parva-antigen-specific immune t cells have been shown to produce cytokines in response to stimulation with parasitized cells, and t. parva-infected lymphocytes produce and consume t-cell growth factors and interleukin-2 (il-2). to ascertain the role of t-cell cytokines on t. parva infections, we evaluated recombinant gamma in ...19911937812
characterization of a polymorphic immunodominant molecule in sporozoites and schizonts of theileria parva.this study examines several aspects of a polymorphic, immunodominant molecule (pim) found in the protozoan parasite, theileria parva. the antigen is present in all t.p. parva stocks examined, and in the related subspecies, t.p.bovis and t.p.lawrencei. it is the predominant antigen recognized by antisera from immune cattle on western blot analysis of schizont-infected lymphocytes, and is the only antigen which has been shown to react with anti-schizont monoclonal antibodies (moabs) on western blo ...19911901640
activity of buparvaquone against theileria cervi in white-tailed deer.buparvaquone, a naphthoquinone with known efficacy against theileria parva parva in cattle, was tested for activity against theileria cervi piroplasms in both an in vitro culture system and in vivo in experimentally infected white-tailed deer. the in vitro data showed a significant decrease in the incorporation of 3h-hypoxanthine by infected red blood cells treated with buparvaquone when compared to that seen with imidocarb and chloroquine treatment. in both intact and splenectomized deer treate ...19911902608
strain specificity of bovine theileria parva-specific cytotoxic t cells is determined by the phenotype of the restricting class i mhc.to determine whether the major histocompatibility complex (mhc) phenotype of cattle could affect the parasite strain specificity of immunity to theileria parva by influencing the antigenic specificity of theileria-specific cytotoxic t lymphocytes (ctl), we investigated the parasite strain specificity of theileria-specific ctl clones derived from cattle of different class i mhc phenotypes. thirty-one class i-restricted ctl clones were generated from four cattle immunized with the muguga stock of ...19901968884
epidemiological observations on theileriosis following field immunisation using infection and treatment.thirty-seven high grade cattle were immunised against corridor disease (theileria parva lawrencei infection) on a farm with a history of heavy and often lethal theilerial challenge. nineteen cattle were immunised by treating with two doses of long-acting oxytetracyclines given at 20 mg/kg on days 0 and 4 after sporozoite stabilate inoculation, while the other 18 were treated with naphthoquinone buparvaquone, given as a single dose of 2.5 mg/kg simultaneously with stabilate inoculation. all the c ...19911907045
geographical information systems for studying the epidemiology of cattle diseases caused by theileria parva.data on selected variables which influence the epidemiology of cattle diseases caused by theileria parva were assembled and entered in a computerised geographical information system. variables studied included the distributions of major hosts (cattle and buffalo), the vector ticks (rhipicephalus appendiculatus and related species) and the reported presence of east coast fever, corridor disease and january disease. in addition, the distribution of climatic suitability for r appendiculatus was ass ...19902327044
theileria parva: influence of vector, parasite and host relationships on the epidemiology of theileriosis in southern africa.the protozoan parasite theileria parva, transmitted by the ixodid tick rhipicephalus appendiculatus, is the cause of east coast fever (ecf) and the related syndromes of corridor disease and january disease in cattle of eastern, central and southern africa. it is likely that buffalo (syncerus caffer) are the natural host of t. parva. in eastern and southern africa, there exists both buffalo-adapted and cattle-adapted t. parva. disease caused by buffalo-adapted parasites is called corridor disease ...19911907728
a simple and efficient method for purifying and quantifying schizonts from theileria parva-infected cells.an improved method for the purification of theileria parva schizonts from infected bovine cells is described. the technique is simpler and more rapid than previously described methods and gives rise to greater yields of schizonts with negligible contamination by host-cell components. in addition, a fluorescent staining technique was developed whereby live schizonts purified from infected cells can be enumerated and sorted using the flow cytometer. an assessment of the quality of schizonts prepar ...19911924254
how individual cells develop from a syncytium: merogony in theileria parva (apicomplexa).the central problem for theileria parva during merogony is how to form numerous individual, uninucleate merozoites from a syncytial schizont so that each merozoite contains a single nucleus and a prescribed assortment of organelles. the way t. parva packages all the requisite organelles into free merozoites is by binding these organelles to the nuclear envelope, which in turn becomes associated, both directly and through the rhoptry complex, with the schizont plasma membrane. formation of the me ...19921569119
cytokines inhibit the development of trophozoite-infected cells of theileria annulata and theileria parva but enhance the proliferation of macroschizont-infected cell lines.the following bovine (bo) and human (hu) cytokines--bo rtnf-a, bo rifn-g, hu ifn-a, hu ril-1, hu ril-2--significantly inhibited the in vitro development of trophozoite-infected cells of three stocks of theileria annulata and of theileria parva (muguga). however, none of these cytokines inhibited the proliferation of established t. annulata or t. parva macroschizont-infected cell lines. indeed, bo rtnf-a and hu ril-2 consistently enhanced the proliferation of macroschizont-infected cell lines of ...19921570169
restriction mapping of the genome of the protozoan parasite theileria parva.we have used a modified linking clone strategy and pulsed-field gel electrophoresis to derive a map of the 29 sfi i and 4 not i sites in the 10 million base pair genome of the protozoan parasite theileria parva. this was achieved in the absence of classical genetic information. the map reveals four chromosomes. several genes, including those for parasite antigens, have been located on the map, as has the single locus carrying the major repetitive sequence in this organism. the map forms the basi ...19921608931
constitutive il-2 mrna expression in lymphocytes, infected with the intracellular parasite theileria parva.theileria parva-infected lymphoblastoid cell lines of t or b cell origin were examined for il-2 mrna expression. t. parva-infected t cell lines could be of the cd4-cd8-, cd4+cd8-, cd4-cd8+, or cd4+cd8+ phenotype and express alpha beta or gamma delta tcr. by northern blot analysis and amplification by the polymerase chain reaction, il-2 mrna could be detected in all t. parva-infected cell lines tested. il-2 mrna expression was also shown to be dependent on the continuous presence of the parasite ...19921624803
characterisation of the gene encoding a 104-kilodalton microneme-rhoptry protein of theileria parva.a neutralizing antiserum, c16, raised against sporozoites of theileria parva parva was used to screen a lambda gt11 expression library of t. parva parva (muguga) genomic dna fragments. proteins encoded by one phage clone, lambda tps-17, were reactive with the c16 antiserum. detailed characterisation of the dna insert showed it to encode determinants found on four theilerial antigens of approximately 104, 90, 85 and 35 kda. the sequence encoded by the clone is expressed during sporogony as a sing ...19901689460
biochemical characterization of activation-associated bovine class i major histocompatibility complex antigens.utilizing a 'sandwich' elisa assay we have been able to demonstrate that mab w6/32, b1g6 and il-a19 are reactive with three different monomorphic determinants on bovine class i major histocompatibility complex (mhc) molecules. sequential immunoprecipitations performed with the mab revealed that class i molecules on pbm comprise a single population with respect to reactivity with the mab in that the beta 2m-associated proteins bear all three epitopes. by contrast, tcgf-driven lymphoblasts and cel ...19892481992
identification of lambda gt11 clones encoding the major antigenic determinants expressed by theileria parva sporozoites.an antiserum, c16, was raised in cattle against freeze-thawed extracts of sporozoites of theileria parva (muguga). this antiserum, which neutralizes sporozoite infectivity in vitro, identified theileria-specific antigens having approximate molecular masses of 105, 90, 85, 69, 67, 52, 47, and 43 kilodaltons (kda) on western blots (immunoblots) of infected tick salivary gland extracts. the antiserum was used to screen an expression library of t. parva (muguga) genomic dna fragments. three recombin ...19901692810
sfii and noti polymorphisms in theileria stocks detected by pulsed field gel electrophoresis.dnas of theileria parva parva, t. p. lawrencei, t. p. bovis and theileria mutans stocks, from kenya, uganda, zanzibar and zimbabwe were digested with either sfii or noti and analysed using contour-clamped homogeneous electric field (chef) and field-inversion gel electrophoresis (fige). the sfii-digested t. parva genomic dna resolved into approximately 30 fragments while the noti digestion produced between 4-7 bands. the summation of the sizes of sfii fragments gave an estimate of 9-10 x 10(6) ba ...19901972977
distinction of naive and memory bocd4 lymphocytes in calves with a monoclonal antibody, cc76, to a restricted determinant of the bovine leukocyte-common antigen, cd45.a murine igg1 monoclonal antibody (mab), cc76, has been produced that, based on findings of the relative molecular mass of polypeptides that it recognized, staining of leukocytes in blood and tissues, and the biological properties of the t lymphocyte subpopulations with which it reacts, is considered to identify an isoform of the leukocyte common antigen (lca) family of molecules in cattle. the mab is more similar to human cd45r which detect products requiring the presence of the b exon within t ...19911716214
dna probes detect theileria parva in the salivary glands of rhipicephalus appendiculatus ticks.the ability of theileria parva-specific dna probes to detect t. parva sporoblasts and sporozoites in samples prepared from the salivary glands of infected rhipicephalus appendiculatus ticks was evaluated. the two dna probes used, pgtpm-23 and igtpm-58, were selected from a genomic library of t. parva (muguga) piroplasm dna. in all, 25-200 adult ticks infected with each of 6 different t. parva stocks were tested. one salivary gland from each tick was processed for dna hybridization, whereas the o ...19911792229
re-assessment of tick control after immunization against east coast fever in the eastern province of zambia.east coast fever, caused by the protozoon theileria parva and transmitted by the ixodid tick rhipicephalus appendiculatus is one of the most important cattle diseases in east and central africa, responsible for considerable direct losses and necessitating expensive control measures. traditionally, the disease was controlled by means of intensive tick control. the belgian animal disease control project was requested to study the disease epizootiology and vector ecology in order to formulate and i ...19911793284
theilerial parasites isolated from carrier cattle after immunization with theileria parva by the infection and treatment method.groups of cattle were immunized with 10(-2) dilutions of sporozoite stabilates of theileria parva lawrencei derived from african buffaloes either alone or in combination with theileria parva parva derived from cattle and concomitant treatment with either long or short-acting formulations of oxytetracyline. at 90 or 120 days after infection, uninfected rhipicephalus appendiculatus nymphal ticks were applied to individual immunized cattle and the resultant adults ticks were applied to individual s ...19892508037
a single exon codes for the enzyme domain of a protozoan cysteine protease.theileria parva is an intracellular protozoan parasite of cattle. we have determined the nucleotide sequence of a gene and cdna coding for a cysteine protease of t. parva. the gene is divided into two exons. the first exon codes for a signal sequence and for part of the "pro" region of the zymogen. the second exon codes for the remainder of the pro region, including residues thought to be involved in zymogen processing, and for the entire enzyme domain. part of this exon cross-hybridizes, at hig ...19902120221
low-dose oral administration of human interferon alpha can control the development of theileria parva infection in cattle.two natural human interferon alpha preparations, (nhuifn-alpha [cantell]) and (nhuifn-alpha [isi]), were used for the oral treatment of cattle experimentally infected with theileria parva parva. in the first experiment, 8 friesian bulls were inoculated with a 1 in 10 dilution of a sporozoite stabilate of t.p. parva (marikebuni) stock. four of the cattle were treated daily with 1 international unit/kg body weight (i.u./kg bwt) of nhuifn-alpha (cantell) from day -2 to day 8 p.i. none of the 4 calv ...19902124670
[activation of trans-acting transcription factors in t-lymphocytes infected by the intracellular parasitic protozoan theileria parva].the intracellular protozoan parasite, theileria parva, causes a lymphoproliferative disease of t-cells in cattle and uncontrolled lymphocyte proliferation in culture. we have identified and characterized in infected cells the trans-acting transcription factors nf-kappa b, ap1 and nf1 controlling lymphocyte-specific expression of several genes. theileria infected lymphocytes contain constitutively high levels of active nf-kappa b in nuclear fraction. factor ap1 had high levels of binding activity ...19911874431
protein changes in bovine lymphoblastoid cells induced by infection with the intracellular parasite theileria parva.protein and glycoprotein changes induced in bovine lymphoblasts by infection with theileria parva were analyzed by high-resolution two-dimensional gel electrophoresis. uninfected and infected cloned bovine t and b lymphoblasts were biosynthetically labeled with [35s]methionine and their two-dimensional autoradiographic patterns were compared with each other and with the pattern obtained using purified labeled schizonts. ten proteins were found in infected cells which were not present in uninfect ...19892514355
immunization of cattle against theileria parva bovis and their exposure to natural challenge.theileria parva bovis isolates were tested for their immunizing capacity under natural field challenge on willsbridge farm in the highveld of zimbabwe. fifteen susceptible sussex yearlings were immunized with the boleni stock and 15 with a mixture of three isolates from the farm, using tick-derived sporozoite stabilates. no chemoprophylaxis was used. a dose of 0.1 ml of stabilate appeared to be safe in preliminary laboratory experiments, but the reactions were severe in the sussex cattle and one ...19902125158
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