Letter: Activation or unblocking of T lymphocytes

Multimodal immunotherapy of primary gastrointestinal tumors in rats. 1. Histologic correlation

The effect of multimodal immunotherapy was studied in rats bearing primary gastrointestinal tumors induced by 1,2-dimethylhydrazine dihydrochloride. Multimodal immune manipulation consisted of combinations of splenectomy, C. parvum, unblocking serum, unblocked lymphoid cells, and levamisole. Such immunologic intervention resulted in significant inhibition of tumor growth, and their metastasis. Ten of 10 untreated rats, 8 of 8 rats treated with splenectomy alone and 10 of 10 rats treated with normal rabbit serum died of progressive tumor growth. None of the rats treated with combinations of splenectomy, unblocking serum, unblocked lymphoid cells, C. parvum and levamisole succumbed to progressive tumor growth during the observation period. The histologic evidence of tumor destruction was obtained in 18 of 22 tumors in rats of groups receiving multimodal immunotherapy.

Serum factors influencing spontaneous rosette formation by lymphocytes of pregnant women

The effect of sera from pregnant women on the percentage of spontaneous rosette-forming peripheral lymphocytes was investigated. Pregnancy lymphocytes displayed a significantly lower capacity to bind SRBC than control male lymphocytes. However, after an exhaustive washing, it was possible to demonstrate a significant increase of spontaneous rosettes formed by pregnancy lymphocytes. It was found that the incubation of pregnancy-washed lymphocytes with pregnancy but not homologous male serum restored to depressed levels the values of rosette-forming peripheral lymphocytes. This blocking activity was significantly higher with autologous serum than homologous pregnancy serum. Control lymphocytes were unaffected both by washing and by incubation with pregnancy sera. The blocking activity was found in the same ion-exchange chromatography fraction of pregnancy serum where paternal HLA antigens could be demonstrated, and was reproduced by a soluble HLA preparation from the husband's lymphocytes.