Browsing by Author "Stagg, D.A."

Now showing 1 - 19 of 19

Adaptation and Possible Attenuation of Theileria Parva-Infected Cells Grown in Irradiated Mice
(1976) Irvin, A.D.; Brown, C.G.D.; Stagg, D.A.; Kanhai, G.K.; Kimber, C.D.; Radley, D.E.; East African Veterinary Research Organisation, Muguga, P.O. Box 32, Kikuyu, Kenya
Theileria parva-infected bovine lymphoid cells were taken from 8 cattle immediately after death from East Coast fever (ECF). Cells were inoculated into groups of irradiated Swiss and athymic nude mice. Cells became established in one group of Swiss mice and 2 groups of athymic mice. Development of cells in mice only occurred if cells concurrently established in culture; when establishment in culture was delayed, cells failed to develop in mice. Cells from one of the isolates in athymic mice were passaged 6 times through further mice. On inoculation of these mouse-passaged cells into cattle, the animals underwent mild reactions and subsequently resisted a lethal ECF challenge. The possibility of vaccinating cattle against ECF by means of mouse passaged cells merits further study.
Cell Fusion Using Sendai Virus to Effect Interspecies Transfer of Cell Associated Parasite
(1974) Irvin, A.D.; Brown, C.G.D.; Kanhai,G. K.; Stagg, D.A.; Rowe, L.W.; Institute for Research on Animal Diseases, Compton, United Kingdom; FAO ; Central Veterinary Laboratory, United Kingdom; Central Veterinary Laboratory
Baby hamster kidney (BHK) cells were fused with Theileria parva-infecled bovine lymphoid cells, using u.v. light-inactivated Sendai virus. The resultant hamster/bovine heterokaryons were shown to be infected with T. parva. In some cases parasites were detected in cells which apparently contained only BHK nuclei.
Cell Fusion, using Sendai virus, to Effect Inter-Species Transfer of a Cell-Associated Parasite (Theileria Parva).
(1974) Stagg, D.A.; Brown, C.G.D.; Rowes, L.W.; Irvin, A.D.; Kanhal, G.K.; UNDP/FAO Tick-borne Diseases Project: East African Veterinary Research Organization
The production of interspecific heterokaryons by virus-induced cell fusion was first performed by Harris & Watkins (1965). Since that time the technique has been widely used in a variety of fields but its application in the field of parasitology has not so far been exploited. We have used the technique to effect inter-species, transfer of an intra-cellular host specific parasite (Theileria parva) the causative organism of East Coast fever of cattle.
Cell-Mediated Immunity to Theileria-Transformed Cell Lines
(1979) Pearson, T.W.; Lundin, L.B.; Dolan, T.T.; Stagg, D.A.; International Laboratory For Research in Animal Diseases Kenya Agricultural Research Institute Veterinary Research Muguga
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 year1. Infected animals can recover from ECF either naturally2 or after treatment with tetracyclines3 or menoctone4 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 suspected5,6 but never decisively shown. A major difficulty in studying immunity to ECF has been the lack of inbred animals for studying Theileria-specific immunity in the absence of allogeneic histocompatibility barriers. We have avoided this problem by measuring cell-mediated immune responses in a syngeneic system in vitro. Unidirectional mixed lymphocyte cultures (MLC) were set up using bovine peripheral blood lymphocytes (PBL) as responder cells and autologous cell lines transformed in vitro by T. parva as stimulator cells. In these cultures, DNA synthesis was induced in PBL from both normal and Theileria-immune animals. However, cytotoxic lymphocytes were induced only in cultures containing responder lymphocytes from Theileria-immune cattle. The results show that Theileria-transformed cells express antigens which are recognised by effector cells and provide evidence that cell-mediated cytotoxic mechanisms function in immunity to ECF.
Detection of Antibody to Theileria Parva Schizonts and Cell Surf Ace Membrane Antigens of Infected L Ymphoblastoid Cells by Immunoperoxidase Techniques
(1984) Cowan, K.M.; Dolan, T.T.; Teale, A.J.; Youngs, A.S.; Stagg, D.A.; Groocock, C.M.; US Department of Agriculture and Corporative Research British Overseas Development Administration KARI Veterinary Research Department Muguga Kikuyu
Peroxidase-labeled antibody procedures were described for detecting bovine antibodies reactive with intracellular Theileria parva schizonts and cell surface membrane antigens of infected lymphoblastoid cells. Indirect tests were performed where the reacting bovine antibodies were localized with affinity purified rabbit-anti-bovine IgG coupled to horseradish peroxidase. A 4- to 8-fold increase in sensitivity for detecting bovine antibodies was obtained with unlabeled rabbit-anti-bovine IgG which in turn was detected with peroxidase labeled goat-anti-rabbit IgG. The T. parva infected cells used as antigen were attached to poly-I-lysine treated glass slides and all reaction steps were performed on the slides. The intracellular schizonts and cell surface staining reactions were dependent upon the status of the cells; acetone-fixed cells were required for schizont reactions and viable unfixed cells for cell surface membrane reactions. Sera from cattle stimulated in various ways with T. parva were examined by the techniques. Cattle infected by stabilate inoculation or inoculated with infected autologous lymphoblastoid cells developed relatively high levels of antibody to schizonts, but no detectable antibody to cell . surface membrane antigens. This would indicate that parasite antigens do not occur on the surface of infected lymphoblasts. Cattle inoculated with infected allogeneic lymphoblasts developed low-levels of antibody to schizonts and readily demonstrable antibody to cell surface antigens. The immunoperoxidase procedures have certain advantages over immunofluorescence in that light microscopy is used; therefore, the reactions do not fade which permits a more detailed examination and provides a relatively permanent record, the preparations can be counterstained, and the reagents may be used for immunoelectron- microscopy. The procedures could provide suitable alternatives to immunofluorescence methods for East Coast fever investigations and other systems having intracellular and/or cell surface membrane antigens.
Establishment of Theileria Parva Infected Bovine Tissue Culture in Swiss and Athymic Mice
(1977) Irvin, A.D.; Brown, C.G.D.; Stagg, D.A.; East African Veterinary Research Organisation; Institute of Research on Animal Diseases; Central Veterinary Laboratory
Theileria parva-infected bovine lymphoid cells, grown in culture, were inoculated by different routes into neonatal and adult Swiss mice immunosuppressed by irradiation, thymectomy or inoculation of anti-lymphocyte serum. Tumour-like masses, composed of parasitized bovine lymphoid cells, formed at the site of subcutaneous inoculation in immunosuppressed neonatal and adult mice, but consistent establishment of cells following intra-peritoneal inoculation occurred only in neonatal mice. In all cases the degree of cellular establishment was proportional to the degree of immunosuppression. The best “take” was in irradiated neonatally thymectomized mice. Cells underwent short-term multiplication in mice but, as immune competence returned, the cells were rejected. There was no evidence that cells, on passage, became more adapted to grow in mice, nor that mouse cells became parasitized. Culture-derived cells were also inoculated subcutaneously into irradiated and non-irradiated nu/nu, nu/+ and Swiss mice. Tumour-like masses, composed of parasitized bovine lymphoid cells, developed at the site of inoculation in all irradiated mice. In nu/+ and Swiss mice these masses regressed after 2–3 weeks, but in the athymic nu/nu mice there was generally no rejection or cellular degeneration and parasitized cells became widely disseminated in the host's tissues and organs, in some cases causing death. T. parva-infected cells could not be established in non-irradiated nu/nu mice, nor when irradiated nu/nu mice were inoculated by the intra-peritoneal route. “Take” in irradiated neonatal nu/nu mice was also poor. Cells were passaged three times in irradiated nu/nu mice inoculated subcutaneously and it seems probable that indefinite passage of T. parva in mice can now be achieved.
Establishment of Theileria Parva-Infected Bovine Tissue Culture in Swiss and Athymic (Nude) Mice
(1977) Irvin, A.D.; Brown, C.G.D.; Kanhai, G.K.; Stagg, D.A.; East African Veterinary Research Organization, Muguga, P.O. Box 32, Kikuyu Kenya
Theileria parva-infected bovine lymphoid cells, grown in culture, were inoculated by different routes into neonatal and adult Swiss mice immunosuppressed by irradiation, thymectomy or inoculation of anti-lymphocyte serum. Tumour-like masses, composed of parasitized bovine lymphoid cells, formed at the site of subcutaneous inoculation in immunosuppressed neonatal and adult mice, but consistent establishment of cells following intra-peritoneal inoculation occurred only in neonatal mice. In all cases the degree of cellular establishment was proportional to the degree of immunosuppression. The best “take” was in irradiated neonatally thymectomized mice. Cells underwent short-term multiplication in mice but, as immune competence returned, the cells were rejected. There was no evidence that cells, on passage, became more adapted to grow in mice, nor that mouse cells became parasitized. Culture-derived cells were also inoculated subcutaneously into irradiated and non-irradiated nu/nu, nu/+ and Swiss mice. Tumour-like masses, composed of parasitized bovine lymphoid cells, developed at the site of inoculation in all irradiated mice. In nu/+ and Swiss mice these masses regressed after 2–3 weeks, but in the athymic nu/nu mice there was generally no rejection or cellular degeneration and parasitized cells became widely disseminated in the host's tissues and organs, in some cases causing death. T. parva-infected cells could not be established in non-irradiated nu/nu mice, nor when irradiated nu/nu mice were inoculated by the intra-peritoneal route. “Take” in irradiated neonatal nu/nu mice was also poor. Cells were passaged three times in irradiated nu/nu mice inoculated subcutaneously and it seems probable that indefinite passage of T. parva in mice can now be achieved.
Hybrid Cells, Infected with Theileria Parva Formed by Fusion Hamster and Mouse Cells with Parasitised Bovine Lymphoid Cells.
(1975) Brown, C.G.D; Stagg, D.A.; Irvin, A.D.; Kanhai, G. K.; Rowe, L.W.; East African Veterinary Research Organisation
Bovine lymphoid cells from a culture line parasitised with Theileria were fused to mouse heart and baby hamster kidney cells grown as monolayers using inactivated Sendai virus the resultant heterokaryons contained macroschizonts of T.Parva .
Hybrid Cells, Infected with Theileria Parva, Formed by Fusion of Hamster and Mouse Cells with Parasitised Bovine Lymphoid Cells
(1975) Irvin, A.D.; Brown, C.O.D.; Stagg, D.A.; Kanhai, O.K.; Rowe, L.W.; UNDP/FAO Tick-borne Diseases Project, East African Veterinary Research Organisation, Muguga, Kenya
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 macro schizonts of T parva. Macro schizonts also occurred in cells that apparently contained only BHK or MH nuclei. Parasites underwent varying degrees of development; in some cases, micro schizonts resulted, and in other cases massive atypical parasite masses were formed. Fusion occurred more readily between hamster and bovine cells than between mouse and bovine cells.
Immunization of Cattle against Theileriosis Using Varying Doses of Theileria Par VA Lawrencei and T. Par VA Par VA Sporozoites and Ox tetracycline Treatments
(1988) Ndungu, S.G.; Young, A.S.; Stagg, D.A.; Mutugi, J.J.; Maritim, A.C.
Immunization of cattle against theileriosis using varying doses of Theilera parva lawrencei and T parva parva sporozOtes and oxytetracycline treatments. International Journal for Parasitology 18: 453-461. Theileria parva lawrencel and T parva parva parasites, from three sources (two from African buffalo, SWlcerus caifer, and one from indigenous cattle, Bos indicus) iwlated from two areas of Kenya, were chosen for invetigations mto immunization of cattle agaimt thellenonsis. Varying concentration of stabllates were used to Infect cattle singly in one experiment and In combination in another experiment, wIth one or two treatments with either long- or short-acting formulations of oxytetracyclines, respectively. It was found that high concentrations with T parva lawrencei stabilates (10°) were not controlled satisfactonly by oxytetracyclines but with concentration of stabilate at 10- 1 or particularly 1O-~ It was possible to Induce sub-climcal theileriosis with the development of antibodies to T pan'a. Both short- and long-acting formulatIOns of oxytetracyclines appeared to be equally effective. Some chrome effects were seen after immumzation but these were not usually detected when lower concentratlom of stabilate were given. Cattle Immunized by this procedure were shown to be immune to homologow. and heterologous challenge and some were demomtrated to become T parva carriers.
The incidence of Theilerial Parasites in East African Buffalo (Syncerus caffer).
(1978) Young, A.S.; Brown, C.G.; Burridge, M.J.; Grootenhuis, J.G.; Kanhai, G.K.; Purnell, R.E.; Stagg, D.A.; Immunological Research on Tick-borne Cattle Diseases and Tick Control Project; East African Veterinary Research Organisation, Muguga
245 buffalo from 13 areas of East Africa were examined for theilerial infections. The vast majority of buffalo (97.1%) examined had piroplasms in their erythrocytes. Theileria lawrencei was isolated from the buffalo by tick feeding and cell culture and was found to be common in most of these buffalo populations. Also over 50% of the buffalo had indirect fluorescent antibody (IFA) titres to T. lawrencei. T. mutans was only isolated from 3 buffalo populations but is probably common. Haematoxenus sp. was detected in the blood of 56% of the buffalo sampled. In the light of these results the role of buffalo as a reservoir of cattle pathogenic theilerioses in East Africa is discussed.
Infection and Transformation of Bovine Lymphoid Cells In Vitro by Infective Particles of Theileria Parva
(1973) Brown, C.G.D.; Stagg, D.A.; Purnell, R.E.; Kanhai, G.K.; Payne, R.C.; East African Veterinary Research Organization Muguga, PO Box 32, Kikuyu
Techniques recently developed in this laboratory can be used to infect cattle reproducibly with East Coast fever with infective particles of Theileria parva collected from the tick vector, Rhipicephalus appendiculatus. Infective particles can be collected either as in vitro tick feed material by inducing prefed, infected ticks to salivate into capillary tubes containing foetal calf serum1, or as ground tick supernatant obtained by grinding the ticks in Eagle's minimum essential medium with Earle's salts (MEM) supplemented with bovine plasma albumin (Fraction V from bovine plasma) (BPA) and collecting the supernatant2.
Infection of African Buffalo and Cattle with Theileria Parva Lawrencei after Serial Passage in Cattle
(1987) Grootenhuis, J. G.; Young, A.S.; Stagg, D.A.; Leitch, B.L.; Dolan, T.T.; Conrad, P.A.; Veterinary Research Laboratory, Kabete; Kenya Agricultural Research Institute; International Laboratory for Research on Animal Diseases
The infectivity of a Theileria parva lawrencei stabilate, from a stock derived from an African buffalo (Syncerus caffer) in the Serengeti National Park, Tanzania, was investigated. In the first experiment a buffalo and three cattle were inoculated with a stabilate from a stock passaged three times in cattle. All cattle developed fatal theilerial infections. Isolations from the buffalo by tick feeding and cell culture isolation showed that it was infected with T p lawrencei at the time of inoculation, but the second isolation made 19 days after inoculation behaved like T p parva in cattle, developing a high parasitosis, while the third isolation made three months later behaved like T p lawrencei with low parasitosis. It was concluded that two biological types of T parva could exist in a buffalo at one time, but it was not shown that the buffalo had become a carrier of T p lawrencei adapted to cattle. In the second experiment two buffaloes and three cattle were inoculated with T p lawrencei (Serengeti) stabilate which had been passaged six times through cattle and ticks. The two buffaloes had mild theilerial infections and developed serological titres in the indirect fluorescent antibody test, but the cattle had fatal infections. Tick and cell culture isolations of T parva were possible during the clinical reactions of the buffaloes, but no carrier state was demonstrated. Theileria-infected cell lines were established from the buffaloes and the cattle and were examined using monoclonal antibodies against T parva schizonts. The macroschizonts in the cell lines isolated from the buffaloes and cattle had different staining profiles with the monoclonals, indicating either antigenic change of the parasite after inoculation into the buffalo or the presence of different antigenic types in the stabilate.
Infection of Mammalian Cells with Theileria Species
(1983) Stagg, D.A.; Young, A.S.; Leitch, B.L.; Grootenhuis, J.G.; Dolan, T.T.; Veterinary Research Department, Kenya Agricultural Research Institute, Muguga, P.O. Box 32, Kikuyu, Kenya
Experiments were carried out to determine the susceptibility of mammalian cells to infection with different species of Theileria in vitro. Sporozoites of Theileria parva (parva), Theileria parva (lawrencei) and Theileria taurotragi were isolated from Rhipicephalus appendiculatus ticks by grinding infected ticks in medium, filtering the suspension and concentrating by centrifugation. The sporozoites were used in attempts to infect in vitro peripheral blood leucocytes harvested from 16 different mammalian species which included 12 species of Bovidae from 6 different sub-families. The technique was shown to be both sensitive and reproducible. The sporozoites of T. parva (parva) infected and transformed cells from 2 species of the sub-family Bovinae, the two cattle types and African buffalo. Theileria parva (lawrencei) infected and transformed cells from the two cattle types, African buffalo and Defassa waterbuck. Theileria taurotragi sporozoites infected in vitro cells from 11 different species of Bovidae which were members of 6 sub-families; Bovinae, Tragelaphinae, Reduncinae, Alcelaphinae, Antilopinae and Caprinae. Transformed lymphoblastoid cell lines were established from 7 of the species infected. Sporozoite attachment and infection was not observed with non-susceptible bovid host cells, nor were any of the non-bovid leucocytes infected by the parasites. The host range observed in this study corresponded to the known host range in vivo.
Phagocytosis of Trypanosoma (Nannomonas) congolense by circulating macrophages in the African buffalo (Syncerus caffer)
(1975) Young, A.S.; Kanhai, G.K.; Stagg, D.A.; Immunological Research on Tick-home Cattle Diseases and T ck Control Project‡, East African Veterinary Research Organisation, Muguga, PO Box 32, Kikuyu, Kenya
Nineteen African buffalo were short in the Mara region of Kenya. Leucocytes were separated from the buffalo samples by sedimentation and centrifugation. In leucocyte smears of six buffalo, trypanosomes were detected and in two of them, high levels of phagocytosis of Trypanosoma (Nannomonas) congolense by circulating macrophages were demonstrated.
The Response of Bos Taurus and Bos Indicus Cattle Types to Inoculation of Lymphoblastoid Cell Lines Infected with Theileria Parva Schizonts
(1982) Dolan, T.T.; Njuguna, L.N.; Stagg, D.A.; Veterinary Research Department, Kenya Agricultural Research Institute, Kikuyu, Kenya
In a preliminary experiment eight Bos indicus type cattle were inoculated with 10(9) cells of a Bos taurus lymphoblastoid cell line infected with Theileria parva schizonts. Four cattle showed patent infections and one died of theileriosis. On challenge of the surviving cattle with a tick derived stabilate of the same stock of T. parva no animal died of theileriosis. To test the susceptibility of Bos taurus and Bos indicus cattle to cell lines of both cattle types infected with T. parva of the same stock, 10(9) cells of each cattle type were inoculated into five cattle of each type. Bos taurus cattle had a higher susceptibility to infection regardless of the origin of the donor cells. Two Bos taurus type cattle receiving Bos taurus cells died of theileriosis while none receiving Bos indicus cattle died. Both cattle types were more susceptible to infection with cells derived from their own cattle type. All surviving Bos indicus and Bos taurus cattle were immune to lethal stabilate challenge. The possibility that the histocompatibility type of the donor cells influences the success of the immunization is discussed.
Studies on Cell Fusion Between Babesia Rodhaini-Infected Mouse Erythrocytes and Baby Hamster Kidney Cells
(1975) Irvin, A.D.; Stagg, D.A.; Kanhai, G.K.; Brown, C.G.D.; Omwoyo, P.L.; East African Veterinary Research Organization, Muguga, P.O. Box 32, Kikuyu, Kenya
Heterokaryons were formed by fusion of B. rodhaini-infected mouse erythrocytes and baby hamster kidney (BHK) cells, using Sendai virus. The erythrocyte membrane rapidly lysed inside the BHK cell cytoplasm releasing free parasites. There was no evidence that parasite multiplication occurred inside the BHK cells, nor that parasitized BHK cells were infective for mice. Transient erythrocyte homokaryons were observed in some preparations. The approach indicates a possible method for the in vitro cultivation of Babesia.
Theileria Lawrencei Infection of Cattle and African Buffalo: Evaluation of a Buffalo Cell Culture Schizont Antigen for the Indirect Fluorescent Antibody Test.
(1974) Burridge, M.J.; Young, A.S.; Stagg, D.A.; Kanhai, G.K.; Kimber, C.D.; East African Veterinary Research Organization, Muguga, PO Box 32, Kikuyu, Kenya
A schizont antigen for the indirect fluorescent antibody test was prepared from culture suspension of African buffalo lymphoid cells infected with Theileria lawrencei (T.l.) macroschizonts. This antigen was compared with Theileria parva and T.l. cell culture schizont antigens prepared from infected bovine cells, using bovine antiserum to parva and T.l. and buffalo antiserum to T.l. Complete cross-identity of these three antigens was found with all antiserum. Five buffalo naturally infected with T.l. had significant antibody titres to all three schizont antigens, using an anti-bovine conjugate in the indirect fluorescent antibody test. The peak antibody titres of these buffalo were between 1:40 and 1:2560 to the three schizont antigens. These results suggest that this test could be usefully employed in epidemological surveys.
Theileria Parva: Effects of Irradiation on a Culture of Parasitized Bovine Lymphoid Cells
(1975) Irvin, A.D.; Brown, C.G.D.; Stagg, D.A.; East African Veterinary Research Organization, Muguga, Kenya
Aliquots of a culture of Theileria parva-infected bovine lymphoid cells were irradiated at 0, 300, 600, 900, and 1200 rads. The short-term effects of irradiation were evaluated on examination of Giemsa-stained smears and on autoradiography of cells labelled with [3H] thymidine. Irradiation inhibited cell division but parasite division did not appear to be inhibited and macro schizont nuclear particles increased in number, frequently to several hundred per schizont. There was no evidence of an increased percentage switch from macro to micro schizont. Apparently viable cells were still present in all cultures 4 days after irradiation.

Kenya Agricultural &
Livestock Research Organization

Browsing by Author "Stagg, D.A."

Social Media Links

Contact Us

Our Address