Immunosuppression in experimental cryptococcosis in rats. Induction of thymic suppressor cells

SOTOMAYOR CE; RUBINSTEIN HR; CERVI LA; MASIH DT; RIERA CM

MYCOPATHOLOGIA

SPRINGER

Lugar: Berlin; Año: 1989 vol. 108 p. 5 - 10

0301-486X

The presence of the microorganism, cortical hyperplasia and germinal centers was detected in the thymus of rats infected with 10(7) viable Cryptococcus neoformans cells and immunized at 7 days afterwards with 2.5 mg (0.1 ml) of human serum albumin (HSA) incorporated to complete Freund´s adjuvant (CFA) (Group 2). There was no modification of the glandular structure in the thymus of the animals only immunized with HSA-CFA (Group 1). The weight of the thymus of group 2, animals infected and immunized, was increased compared with the weight of the thymus of group 1 animals, this became evident by the increase of the thymic index (TI) (p less than 0.005). This rate was obtained calculating the thymus weight/total body weight ratio x 1000. Thymic cells (10(7) cells in 1 ml) obtained from both groups of animals were transferred to normal syngeneic rats of the same sex. The recipient rats were immunized with HSA-CFA 24 h later and 14 days after the transference, the response of delayed-type hypersensitivity (DTH) was studied in them. It could be observed that the thymic cells coming from group 2 animals were capable of suppressing significatively the afferent pathway of the DTH response to HSA when compared with the response of the animals that received cells coming from group 1 rats (p less than 0.0001).