Partial reconstitution of TNP-Ficoll responses and IgG3 expression in Xid mice undergoing graft-vs-host reaction
Golding, H.; Foiles, P.G.; Rittenberg, M.B.
Journal of Immunology 129(6): 2641-2646
1982
ISSN/ISBN: 0022-1767 PMID: 6982935 Document Number: 185235
Primary responses to T-dependent (TD) and T-independent type 2 (TI-2) antigens were previously shown to be differentially affected by allogeneic effects induced in vivo during a graft-vs.-host reaction (GVH). TD responses were suppressed .gtoreq. 80%; TI-2 responses were greatly enhanced, particularly the IgG component, which normally is very low. Isotype analysis of the augmented TI-2 responses showed a marked increase in all 4 IgG subclasses, with an apparent shift from IgG3 to IgG1 dominance in the spleen. This augmentation could have resulted from recruitment of additional precursors from a pool of less mature B1 precursors. This hypothesis was examined in Xid (CBA/N .times. BALB/c)F1 male mice that are deficient in TI-2 responding B cells and have low levels of serum IgM and IgG3. (CBA/N .times. BALB/c)F1 males produced significant numbers of TNP-primed F1-Xid males, which normally give secondary responses only to TD and TI-1 but not to TI-2 antigens, possessed memory that could be elicited by TNP-Ficoll shortly after induction of GVH. These B1 memory responses were characterized by high IgG/IgM ratios and by IgG1 subclass predominance. No B colony-forming cells were detected in spleens of GVH F1 males, indicating that GVH by itself did not induce generalized maturation of the defective B cell lineage in Xid mice. Xid mice contain a pool of immature B1 precursors that can be driven into later stages of differentiation by the relevant antigens acting in concert with strong nonspecific T cell signals.