Browsing by Author "Wagner, G.G."
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Item East Coast Fever: Cultivation In Vitro of Cell-Free Schizonts and Merozoites of Theileria Parva and their Immunogenicity in Cattle(1978) Nyindo, M.B.; Kaminjolo Jr, J.S.; Wagner, G.G.; Lule, M.; East African Veterinary Research. Organization, Muguga, P.O. Box 32, Kikuyu, KenyaCell-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 revealed their structure to be similar to previous descriptions. Cattle inoculated with T parva merozoites and schizonts and later challenge exposed with homologous stabilate developed leukopenia, showed low macroschizont index, and survived longer than unvaccinated controls.Item Immunochemical Studies on East Coast Fever: I. Partial Segregation and Characterization of the Theileria Parva Schizont Antigen(1974) Wagner, G.G.; Brown, C.G.D.; Duffus, W.P.H.; Kimber, C.D.; Crowford, J.G.; Lule, M.; United States Department of Agriculture Co-operative Research Project: UNDP /FAO Immunological Research on Tick-borne Cattle Diseases: Tick Control Project, at the East African Veterinary Research Organization: Tick Control Project, at the Veterinary Research LaboratorySerologically specific antigens of Theileria parva were extracted from schizonts in infected bovine lymphoblast. The antigens were readily detected by complement fixation and immunodiffusion tests. Partial characterization of the antigens was achieved by Sephadex G200 chromatography, density gradient centrifugation, and precipitation in ammonium sulphate solution. The results indicate that the major antigen has a molecular weight in the region of 200,000 to 400,000 with sedimentation coefficient of approximately 7S.Item Immunochemical Studies on East Coast Fever: Ii. Partial Segregation and Characterization of The Theileria Parv a Piroplasm Antigen(1974) Wagner, G.G.; Duffus, W.P.H.; Kimber, CD.; Lule, M.; United States Department of Agriculture Co-operative Research Project: The UNDP /FAO Immunological Research on Tick-borne Cattle Diseases: Tick Control Project, at the East African Veterinary Research Organization: Tick Control Project, at the Veterinary Research LaboratoryABSTRACT: The piroplasm antigens of Theileria parva were isolated from infected bovine erythrocytes either by sonication or by French pressure cell disruption. A soluble bovine erythrocyte antigen was also isolated from both infected and non-infected blood. Both piroplasm and erythrocyte antigens were readily detected by either complement fixation or immunodiffusion tests. Partial characterizations were achieved by Sephadex G200 and Sepharose 2B chromatography, density gradient centrifugation, and precipitation by ammonium sulphate solution. Results indicated that the piroplasm antigen occurred in a wide molecular weight range of 4 to 20 million with an approximate sedimentation coefficient range of 7 to ISS. The Erythrocyte antigen had a molecular weight range of 20 to 40 million with sedimentation coefficient ranging from 3 to 9S. The piroplasm antigens were partially separable from the erythrocyte antigens by differential ammonium sulphate precipitations.Item The Specific Immunoglobulin Response in Cattle Immunized with Isolated Theileria Parva Antigens(1974) Wagner, G.G.; Duffus, W.P.H.; Burridge, M.J.; East African Veterinary Research Organization, Muguga, Kenya Veterinary Research Laboratory, Kabete, KenyaCattle were inoculated with purified Theileria parva piroplasm and/or schizont antigen. Two similar inoculations were given 10 days apart. Serum samples were regularly collected and the indirect haemagglutination (IHA), indirect immunofluorescence (IFA), complement-fixation (CF) and immunodiffusion (ID) tests were used to detect T. parva antibodies. Selected sera were separated by Sephadex G 200 and fractions examined for specific immunoglobulin activity. With the IHA test specific antibody first appeared 4 days post inoculation (dpi) and reached high titres by 8 dpi. With the IFA and CF tests specific antibody also appeared 4 dpi and reached high titres by 8–14 and 10–14 dpi respectively. Specific ID activity was detected as early as 6 dpi and persisted for the length of the experiment. On fractionation of the sera both the IHA and CF tests indicated a sequential production of T. parva IgM and 7S Ig. However, in cattle inoculated with schizont antigen only, a significant 7S Ig component was not detected by the IHA test until 16 dpi, but was demonstrated by the CF test 7 dpi. The IFA test, however, detected anti T. parva activity almost exclusively in the 7S Ig fractions. All cattle were challenged 35–42 dpi with infective T. parva stabilate and all cattle proved fully susceptible. The lack of protection by high titres of specific T. parva immunoglobulin is discussed, together with the data on the differential immunoglobulin response, in relation to previous results.Item Theileriosis: The Exposure of Immunised Cattle in Atheileria Lawrencei Enzootic Area(1974) Cunnigham, M.P.; Brown, C.G.D.; Burridge, M.J.; Irvin, A.D.; Kirimi, I.M.; Purnell, R.E.; Radleys, D.E.; Wagner, G.G.; East African Veterinary Research Organization, Muguga, P.O. Box 32, Kikuyu, KenyaThree groups of steers were exposed to field challenge in a T. lawrencei-enzootic area of Kenya. Four out of five ECF-susceptible steers and four out of five steers immunised against T. parva (Muguga) died of theileriosis, the surviving animals experiencing severe reactions. On the other hand, all five steers immunised against T. parva (Muguga) and a strain of theileria probably homologous with the one present in the area of exposure, survived and only experienced mild reactions. These results indicated that immunisation of cattle with T. parva (Muguga) may not necessarily protect them against field challenge with certain T. lawrencei-type strains, but that immunisation with an apparently homologous strain of theileria may well do so.
