IGA RESPONSES IN XID MICE - ORAL ANTIGEN PRIMES PEYERS PATCH CELLS FOR INVITRO IMMUNE-RESPONSES AND SECRETORY ANTIBODY-PRODUCTION

  • 1 January 1983
    • journal article
    • research article
    • Vol. 131  (6) , 2616-2622
Abstract
Because the gut-associated lymphoreticular tissue (GALT), e.g., Peyer''s patches (PP), of X-linked immunodeficient (xid) mice possesses a subpopulation of mature B cells, the ability of xid mice to respond to the thymic-dependent antigen sheep erythrocytes (SRBC) given by the oral route was characterized. Gastric intubation of SRBC to xid (CBA/N .times. DBA/2) F1 male or CBA/N mice, followed by the in vitro culture of dissociated PP cells with SRBC, resulted in IgM, IgG1, IgG2 and high IgA anti-SRBC plaque-forming cell (PFC) responses. The addition of unprimed PP but not splenic T cells to splenic xid B cell cultures resulted in IgM anti-SRBC PFC responses, suggesting the importance of GALT T cells for support of the immune responses to SRBC by splenic B cells from xid mice. Purified PP T cells from SRBC orally primed xid mice supported in vitro IgA anti-SRBC PFC responses in B cell cultures from either the PP or the spleens of nonprimed xid mice. Higher IgA responses occurred in PP when compared with splenic B cell cultures. Additional evidence that the GALT of xid mice contains functional IgA precursor cells was provided by the finding that cloned H-2k PP T helper cells (PP Th A) supported IgA responses in PP B cell cultures derived from (CBA/N .times. C3H/HeN) F1 male (xid) mice. Splenic B cells from these xid mice, in the presence of PP Th A cells, did not support in vitro respones. Evidently, unique subpopulations of T cells occur in the GALT of xid and normal mice; 1 T cell subpopulation may induce immature B cells to become precursor IgA cells in the PP. A separate GALT T cell subpopulation, e.g., isotype-specific helper T cells, effectively collaborates with mature IgA B cells for the induction of IgA responses to orally administered antigen. When xid mice were gastric intubated with SRBC, followed by i.p. injection of SRBC, good splenic IgA anti-SRBC PFC responses were seen. Salivary and serum IgA antibodies were also detected in these xid mice. The magnitude of the anti-SRBC response in xid mice was lower than that seen in similarly treated normal mice. Apparently, the GALT of both xid and normal mice possess unique populations of T cells that support in vitro responses in xid B cell cultures from either the spleen or the PP, which direct the mature B cell populations present toward IgA isotype-specific responses. Thus, the secretory immune system is operative in these immunodeficient mice and may provide host protection against environmentally encountered pathogens.

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