Suppression of humoral immunity and lymphocyte responsiveness during experimental trypanosoma cruzi infections

C3H/He and C57B1/6 mice were inoculated with 500 Trypanosoma cruzi trypomastigotes (Strain Y). During the acute phase infected mice presented parasitemia and enlargement of lymph nodes and spleens and intracellular parasites were observed in the heart. Examinations of cells derived from spleen and lymph nodes showed increased numbers of IgM and IgG-bearing cells. During the peak of splenomegaly, about day 17 post-infections, splenic lymphocytes showed a marked decrease in responsiveness to T and B-cell mitogens, parasite antigens and plaque forming cells (PFC) to sheep red blood cells (SRBC). Unfractionated or plastic adherent splenic cells from mice, obtained during the acute phase were able to suppress the response to mitogens by lymphocytes from uninfected mice. During the chronic phase. Disappearance of parasitemia and intracellular parasites in the hearts as well as a decrease in spleen size, was observed. These changes preceded the complete recovery of responsiveness to mitogens and T. cruzi antigens by C57B1/6 splenic lymphocytes. However, this recovery was only partial in the C3H/He mice, known to be more sensitive to T. cruzi infection. Partial recovery of humoral immune response also occurred in both strains of mice during the chronic phase

Suppression of humoral immunity and lymphocyte responsiveness during experimental trypanosoma cruzi infections Supresión de la inmunidade humoral y de la respuesta linfocitaria durante la infección experimental con Trypanosoma cruzi

C3H/He and C57B1/6 mice were inoculated with 500 Trypanosoma cruzi trypomastigotes (Strain Y). During the acute phase infected mice presented parasitemia and enlargement of lymph nodes and spleens and intracellular parasites were observed in the heart. Examinations of cells derived from spleen and lymph nodes showed increased numbers of IgM and IgG-bearing cells. During the peak of splenomegaly, about day 17 post-infections, splenic lymphocytes showed a marked decrease in responsiveness to T and B-cell mitogens, parasite antigens and plaque forming cells (PFC) to sheep red blood cells (SRBC). Unfractionated or plastic adherent splenic cells from mice, obtained during the acute phase were able to suppress the response to mitogens by lymphocytes from uninfected mice. During the chronic phase. Disappearance of parasitemia and intracellular parasites in the hearts as well as a decrease in spleen size, was observed. These changes preceded the complete recovery of responsiveness to mitogens and T. cruzi antigens by C57B1/6 splenic lymphocytes. However, this recovery was only partial in the C3H/He mice, known to be more sensitive to T. cruzi infection. Partial recovery of humoral immune response also occurred in both strains of mice during the chronic phase.Ratones C3H/He y C57B1/6 inoculados con 500 tripomastigotes de la cepa Y de T. cruzi muestran durante la fase aguda de la enferme-dad, parasitemia, aumento del bazo y gânglios linfáticos así como parásitos intracelulares en el corazón. Análisis de las células presentes en ganglios linfáticos y bazo presenta aumento de células IgM e IgG. Cuando la esplenomegalia es mayor, alrededor del día 17 postínfección, los linfocitos esplénicos mostraron un descenso marcado en la respuesta a mitógenos de células B y T, antígenos de T. cruzi y células formadoras de placas contra glóbulos rojos de carnero. Células de bazo o células esplénicas adherentes a plástico, obtenidas de ratones durante la fase aguda de la infección suprimen la respuesta a mitógenos de linfocitos normales. Durante la fase crónica, desaparece la parasitemia, los parásitos intracelulares en el corazón y disminuye la esplenomegalia. Estos cambios preceden a la recuperación de la respuesta a mitógenos y antígenos de T. cruzi en linfocitos esplénicos de C57B1/6. Esta recuperación es solo parcial en C3H/He, los cuales son más sen-sibles a la infección. También se encuentra recuperación de la respuesta humoral durante la fase crónica

Suppression of humoral immunity and lymphocyte responsiveness during experimental trypanosoma cruzi infections

C3H/He and C57B1/6 mice were inoculated with 500 Trypanosoma cruzi trypomastigotes (Strain Y). During the acute phase infected mice presented parasitemia and enlargement of lymph nodes and spleens and intracellular parasites were observed in the heart. Examinations of cells derived from spleen and lymph nodes showed increased numbers of IgM and IgG-bearing cells. During the peak of splenomegaly, about day 17 post-infections, splenic lymphocytes showed a marked decrease in responsiveness to T and B-cell mitogens, parasite antigens and plaque forming cells (PFC) to sheep red blood cells (SRBC). Unfractionated or plastic adherent splenic cells from mice, obtained during the acute phase were able to suppress the response to mitogens by lymphocytes from uninfected mice. During the chronic phase. Disappearance of parasitemia and intracellular parasites in the hearts as well as a decrease in spleen size, was observed. These changes preceded the complete recovery of responsiveness to mitogens and T. cruzi antigens by C57B1/6 splenic lymphocytes. However, this recovery was only partial in the C3H/He mice, known to be more sensitive to T. cruzi infection. Partial recovery of humoral immune response also occurred in both strains of mice during the chronic phase.Ratones C3H/He y C57B1/6 inoculados con 500 tripomastigotes de la cepa Y de T. cruzi muestran durante la fase aguda de la enferme-dad, parasitemia, aumento del bazo y gânglios linfáticos así como parásitos intracelulares en el corazón. Análisis de las células presentes en ganglios linfáticos y bazo presenta aumento de células IgM e IgG. Cuando la esplenomegalia es mayor, alrededor del día 17 postínfección, los linfocitos esplénicos mostraron un descenso marcado en la respuesta a mitógenos de células B y T, antígenos de T. cruzi y células formadoras de placas contra glóbulos rojos de carnero. Células de bazo o células esplénicas adherentes a plástico, obtenidas de ratones durante la fase aguda de la infección suprimen la respuesta a mitógenos de linfocitos normales. Durante la fase crónica, desaparece la parasitemia, los parásitos intracelulares en el corazón y disminuye la esplenomegalia. Estos cambios preceden a la recuperación de la respuesta a mitógenos y antígenos de T. cruzi en linfocitos esplénicos de C57B1/6. Esta recuperación es solo parcial en C3H/He, los cuales son más sen-sibles a la infección. También se encuentra recuperación de la respuesta humoral durante la fase crónica