Cellular and humoral immune responses of jirds resistant to Dipetalonema viteae infection.

Jirds with prepatent Dipetalonema viteae infections develop an acquired immunity to challenge infections. The objective of the present study was to observe parasite-specific and nonspecific cellular and humoral immune responses in immune jirds. Splenic hyperplasia was observed in infected jirds during the first 5 weeks of infection. Antigen-reactive spleen cells were observed in the lymphocyte transformation assay at 3 weeks postinfection. A depressed response to concanavalin A (ConA) was seen at 1 week postinfection through week 5. Mitomycin C-treated cells from infected jirds were capable of suppressing the response of normal cells to ConA. Sephadex G-10-nonadherent spleen cells from infected jirds showed elevated responses to D. viteae antigen at 1, 3, and 5 weeks and elevated responses to ConA at 3 and 5 weeks. Filaria-specific antibodies were seen at 1 week postinfection, and titers rose through week 5. Plaque-forming cell production to sheep erythrocytes was not depressed in infected jirds. It was concluded that jirds react immunologically with both cellular and humoral responses during the prepatent period of D. viteae infection. A concurrent immune depression was seen. Its effect on resistance and tolerance remains to be determined.