Modulation of lymphoid cell blastogenic responsiveness to mitogens by Nippostrongylus brasiliensis infection.

Spleen and mesenteric lymph node cell blastogenic responses to the mitogens concanavalin A and lipopolysaccharide and to parasite antigens were examined in vitro following removal from mice undergoing primary or secondary infection with Nippostrongylus brasiliensis. During primary infection spleen cells showed a marked increase in proliferative responsiveness to both mitogens, followed by a marked depression thereafter. During a secondary infection the response of spleen cells to both mitogens remained depressed. In contrast, cells from the mesenteric lymph nodes of infected mice exhibited enhanced responsiveness to Con A and LPS, followed by depression of the response, followed by another cycle of enhancement upon reinfection. Sensitivity of both spleen and especially mesenteric lymph node cells to Nb antigens was greatest at approximately the time of worm expulsion: Day 13 after primary and Day 8 after secondary infection.