Congenital and nursing effects on the evolution of Schistosoma mansoni infection in mice

Modification of the immune response to schistosomal infection in children or offspring born to mother R infected with Schistosoma mansoni has been demonstrated in human and in experimental schistosomiasis. One of the hypothesis to explain this fact could be the transfer of circulating antigens and antibodies from mother to foetus through the placenta or from mother to child by milk. The results of this spontaneous transference are controversial in the literature. In an attempt to investigate these questions, we studied one hundred and twenty offspring (Swiss mice), sixty born to infected-mothers (group A) and sixty born to non-infected mothers (group B). These were percutaneously infected with 50 cercariae/mouse, and divided in six sub-groups (20 mice/sub-group), according to the following schedule: after birth (sub-groups A.I and B.I), 10 days old (sub-groups A.II and B.II) and 21 days old (sub-groups A.III and B.III). After the exposure period, the young mice returned to their own mothers for nursing. Six weeks later, the mice were killed. We obtained the following results: 1) There is transference of antibody to cercariae (CAP), adult worms (SWAP) and egg antigens (SEA) from the infected mothers to the offspring, probably through placenta and milk; 2) Offspring born to infected mothers exhibit much less coagulative hepatic necrosis and show a lower number of eggs in the small intestine and a less intense and predominant exsudative stage of the hepatic granulomas when compared with the exsudative-productive stage of the control groups. The findings suggest that congenital and nursing factors can interfere on the development of the schistosomiasis infection, causing an hyporesponse to the eggs.

Kinetics and histopathology of the ear thickness test for delayed hypersensitivity in murine leishmaniasis.

Camundongos C3H, infectados com Leishmania mexicana durante 3,5 e 8 meses, foram avaliados, atraves do teste de espessamento da orelha, para a reacao de hipersensibilidade retardada aos antigenos de formas promastigotas do parasita. O aumento da espessura da orelha, o qual teve seu pico 48 horas apos a injecao antigenica, foi significantemente maior nos animais infectados do que nos controles nao infectados. A histopatologia do sitio do teste intradermico mostrou intensidade significativamente maior da infiltracao de celulas mononucleares, da congestao vascular e do edema intersticial nos animais infectados, quando comparados com os controles. Houve, tambem, uma correlacao significativa entre a intensidade desses tres achados histologicos, analisados no seu conjunto, e as medidas macroscopicas da espessura das orelhas dos animais infectados. Entretanto, nao houve nenhuma correlacao entre o teste do espessamento das orelhas e os titulos em qualquer um dos tres testes sorologicos efetuados, utilizando-se antigenos especificos. Sao discutidas as possiveis vantagens deste teste de espessamento da orelha, em relacao aos outros testes in vivo, de avaliacao de hipersensibilidade retardada