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9. The Nature of Immunosuppression in <em>Trypanosoma brucei</em> Infections in Mice II. THE ROLE OF THE T AND B LYMPHOCYTES.

Author

Murray, P. K., Jennings, F. W., Murray, M., and Urquhart, G.M.

Subjects
TRYPANOSOMA brucei, IMMUNOREGULATION, LYMPHOCYTES, B cells, ENDOCRINE glands, PROTOZOAN diseases
Abstract

In an investigation of the immunosuppression associated with trypanosomiasis, the thymus-derived lymphocytes (T cells) and the thymus-independent lymphocytes (B cells) in mice with subacute Trypanosoma brucei infections were studied. It was shown that: (a) there was a massive plasma cell response in lymph nodes and spleen which replaced the thymus-dependent areas; (b) a failure of antibody production at the cellular level occurred as shown by the absence of IgM PFC responses to SRBC and lipopolysaccharide; (c) T cells appeared relatively normal as judged by their ability to proliferate following a primary stimulus with oxazolone unless measured during the terminal stages of the disease; (d) immune competence was rapidly restored after treatment with a trypanocidal drug. It appeared that immunosuppression was closely associated with the presence of living trypanosomes, possibly mediated through a B-cell defect. The mechanism whereby this might occur is discussed. [ABSTRACT FROM AUTHOR]

Published
1974

10. The Nature of Immunosuppression in <em>Trypanosoma brucei</em> Infections in Mice I. THE ROLE OF THE MACROPHAGE.

Author

Murray, P. K., Jennings, F. W., Murray, M., and Urquhart, G.M.

Subjects
IMMUNE system, BLOOD cells, TISSUES, TRYPANOSOMA brucei, LYMPHOID tissue, BONE marrow
Abstract

The functional integrity of the mononuclear phagocytic system (MPS) in mice infected with Trypanosoma brucei was investigated with regard to its possible significance in the aetiology of the immunosuppression characteristic of this disease. in infected mice the spleens and lymph nodes were grossly enlarged, and on histological examination it was shown that the MPS of the liver, lymph nodes, spleen and bone marrow was markedly expanded. Macrophages presented an active appearance and often contained cellular debris. Clearance of intravenously injected sheep red blood cells (SRBC) was increased, in that 1 hour after injection, 2-6 times more 51Cr-labelled SRBC had disappeared from the circulation of infected, compared to uninfected mice; this was due largely to an increased uptake by the expanded phagocytic system of the liver. The intrinsic immunogenic potential of individual macrophages appeared to be unimpaired as judged by the ability of SRBC-containing macrophages from infected mice to elicit a response in syngeneic normal recipient mice. It was concluded that the only evidence that immunosuppression might be associated with an altered activity of the MPS was an increased hepatic uptake of particulate antigen with a relative failure of splenic uptake. Together these might be responsible for a reduction in the concentration of antigen in the tissues of an enlarged spleen below the level necessary to initiate the formation of antibody. [ABSTRACT FROM AUTHOR]

Published
1974

11. Anaemia in Trypanosomiasis: Studies in Rats and Mice Infected with Trypanosoma brucei

Author

Jennings, F.W., Murray, P.K., Murray, M., and Urquhart, G.M.

Abstract

The anaemia associated with infections of Trypanosoma brucei TREU 667 in rats and mice is described and discussed. The erythrocytes showed macrocytosis largely due to the increased number of circulating reticulocytes. Normoblastic hyperplasia of the bone marrow and spleen was evident. Circulating hall-life values of Cr51-labelled red cells were reduced in infected rats and the label was excreted in the urine. Fe59was rapidly removed from the serum of infected mice and incorporated into the circulating red cells. There was no increased loss of iron from the body. These results, together with the histological findings of haemosiderosis and marked splenic erythrophagocytosis, all pointed to the anaemia as being haemolytic in origin.

Published
1974
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12. The Pathology of Trypanosoma bruceiInfection in the Rat

Author

Murray, M., Murray, P.K., Jennings, F.W., Fisher, E.W., and Urquhart, G.M.

Abstract

The pathology of trypanosomiasis in rats was studied using a derivative of Trypanosoma brucei TREU 667. This produced a subacute disease lasting over 8 weeks. The results indicated that the disease process could be divided into at least 3 categories.

Published
1974
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13. Response of sheep to experimental concurrent infection with tick-borne fever (Cytoecetes phagocytophila) and louping-ill virus

Author

REID, H.W., BUXTON, D., POW, I., BRODIE, T.A., HOLMES, P.H., and URQUHART, G.M.

Abstract

The pathogenesis of concurrent Cytoecetes phagocytophilaand louping-ill virus infection was studied in two experiments. In the first experiment 18 four- to seven-year-old rams were used. Ten were infected with C phagocytophilaand five days later eight of these animals and the remaining eight sheep were infected with louping-ill virus. The two rams infected with C phagocytophilaalone developed no clinical signs apart from a transient pyrexia, while only three of the eight rams infected with louping-ill virus alone showed mild clinical signs. In marked contrast, all eight dually infected sheep developed severe clinical signs with pronounced depression and dysentery and three died and five were killed in extremis. They developed higher titres of viraemia and the antibody response was depressed while necrotising lesions affecting a variety of organs were detected at post mortem examination. Rhizomucor pucilluswas recovered from these lesions in seven of the eight sheep. A second experiment using 10 sheep, five aged seven months and five aged two to three years, confirmed the findings of the first experiment indicating that the age of the animal had not significantly influenced the initial result. It was concluded that C phagocytophilainfection could enhance the pathogenicity of louping-ill virus and that, operating together, the two pathogens facilitated fungal invasion. It is postulated that sudden deaths in sheep recently transferred to tick-infested pastures may be due to this newly described syndrome.

Published
1986
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14. Theileria parva: the immune status of calves born of dams immunised against East Coast fever

Author

CUNNINGHAM, M.P., BROWN, C.G.D., BURRIDGE, M.J., MORZARIA, S.P., and URQUHART, G.M.

Abstract

Eight Friesian cross cows three months pregnant to a single Friesian bull were immunised against East Coast fever by infection with Theileria parva(Muguga) sporozoite stabilate and treatment with pyrrolidino-methyl tetracycline. They were challenged with the homologous stock four times before calving and a fifth time after calving, and resisted all five challenges which killed all of the five groups of five susceptible controls. Calves born to these hyperimmunised dams were fully susceptible on challenge with the same stabilate, as were susceptible cows from the same farm and their calves. In both instances the calves died three to seven days earlier than the cows which were approximately 10 times heavier. These results show that one- to two-month-old taurine calves from artificially immunised dams are not protected from experimental T parvasporozoite challenge and that there is no inherent calfhood resistance to East Coast fever.

Published
1989
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18. Transfer of Immunity to Fasciola hepaticaInfection by Lymphoid Cells

Author

Corba, J., Armour, J., Roberts, R.J., and Urquhart, G.M.

Abstract

The results of a series of experiments are reported which show that lymphoid cells from rats infected with F. hepaticaare able, when transferred to isogenic recipients, to confer a high degree of protection against a primary infection. A similar result was obtained with a pair of monozygous twin calves. Serum failed to confer any significant protection in either species.

Published
1971
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19. Immunosuppression in trypanosomiasis

Author

Urquhart, G.M.

Subjects
Antigène, Anticorps, Relation hôte parasite, Trypanosomose, Immunologie, L72 - Organismes nuisibles des animaux
Published
1974

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