THE ROLE OF ADULT WORMS IN SUPPRESSING FUNCTIONAL PROTECTIVE IMMUNITYTO HELIGMOSOMOIDES-POLYGYRUS BAKERI CHALLENGE INFECTIONS

Adult Heligmosomoides polygyrus bakeri, radiolabelled with [S-35]-meth ionine were successfully transferred to naive NIH mice by oval gavage. Adult worms and radiolabel could be detected up to 45 days post-infec tion. Adult worms gavaged into immune NIH mice, immunized with a drug abbreviated larval infection, were rejected within 45 days. These adul t worms were unable to ablate the development of a functional protecti ve response to a larval challenge infection in the NIH strain. In fact 50 adult worms were sufficient to significantly immunize NIH mice aga inst a larval challenge infection. However, adult worms were able to s uppress the development of a functional protective response in an outb red CFLP strain. Although a protective immune response could not be el icited to a challenge infection in CBA mice, the presence of gavaged a dult worms was shown to increase the susceptibility of mice to a chall enge infection. For all mouse strains, no significant difference in le vels of L4 antigen-specific serum IgG, IgG1, IgG2a, and IgA existed be tween immune mice and groups of mice immunosuppressed by adult worms. Levels of L4 antigen-specific serum IgG1 were significantly lower in t he poorly immunizable CBA strain compared to CFLP and NIH strains. No correlation was found across mouse strains between the intensity of th e antibody response and the mean worm burdens per animal group. rn add ition, no correlation was found between levels of L4 antigen-specific antibody within each mouse and the loss of worms by individual mice.