Modulation of lymphocyte activation by soluble Brugia pahangi extracts
Leiva, L.E.; Lammie, P.J.
Tropical Medicine and Parasitology Official Organ of Deutsche Tropenmedizinische Gesellschaft and of Deutsche Gesellschaft für Technische Zusammenarbeit 40(3): 327-331
1989
ISSN/ISBN: 0177-2392 PMID: 2617042 Document Number: 339700
The effect of soluble extracts of B. pahangi adult worms and microfilariae on the in vitro mitogen- and antigen-induced proliferative responsiveness of lymphocytes from uninfected and B. pahangi immunized Meriones unguiculatus was investigated. Dose-dependent suppression of lymphocyte proliferative responsiveness to the T-cell mitogen, concanavalin A, ranged from 37 to 86% in the presence of adult or microfilarial extracts, respectively. Similarly, a suppressive effect was observed when other mitogens were used to stimulate the lymphocytes. Microfilarial extracts did not significantly suppress the proliferative response of lymph node cells from B. pahangi immunized jirds to parasite antigen. However, microfilarial fractions higher than 150 000 MW, purified by gel filtration HPLC, consistently suppressed antigen as well as mitogen responses. Soluble extracts of B. pahangi females and microfilariae also suppressed mitogen induced lymphokine production by lymph node cells by 66% and 68% respectively. These findings suggest that a microfilarial-derived antigen may play a role in regulating immune reactivity in filarial infections. The absence of generalized nonspecific immunosuppression in filarial infections, however, suggests that the effect of microfilarial-derived antigens may be restricted to the microhabitat of the parasite.