Spontaneous worm expulsion and intestinal IgA response in mice infected by Vampirolepis nana

Abstract The expulsion of the gastrointestinal parasite Vampirolepis nana was examined in different mouse strains and in immunosuppressed mice infected to different degrees with eggs and cysticercoids. To investigate the immunological mechanism that regulates expulsion, surface-bound mouse immunoglobulins were examined on adult worms. The time to spontaneous expulsion of worms was dependent on strain (C57BL, BDF1 , B6C3F1 < BALB/c < CBA < DBA/2 < C3H; all male mice) and on the degree of infection. In mice given immunosuppressants, the expulsion of worms was prevented completely. Immunoenzyme methods showed that IgA was the only detectable surface-bound antibody found on worms obtained from the intestines of mice of various strains throughout the course of infection. There was no evidence of surface-bound immunoglobulins on adult worms obtained from immunosuppressed mice. There was a good temporal correlation between the time-course of expulsion and the appearance of IgA. The data suggest that the expulsion of V. nana is closely associated with the appearance of parasite-specific IgA.