Incidence and specificities of IgA and IgM anti-AgG autoantibodies in various XXXX strains and colonies.

@entity428 @entity19 @entity6527 @entity19634 @entity74 @entity7173 @entity792 @entity7840
@entity19 , greater than 20 wk old, were tested for the presence of anti-IgG autoantibodies by agglutination and radioimmunoassay. IgA and IgM anti-IgG were found in the 129/Sv, C57BL/6, and @entity7840 /2 strains from the local colony at the International @entity74 ( @entity428 ), at the Institut @entity19634 ( @entity7173 ), and in the endotoxin-resistant C3H/He strain of @entity428 . These strains were negative at Iffa Credo (IC), and at The Jackson Laboratory (JL). Among 33 strains from the latter colony, 129/J, AKR/J, CBA/J, C57L/J, and NZB/BinJ were positive. All were specific pathogen-free and, excepting the NZB/BinJ, are not known to develop systemic @entity792 . These differences between colonies suggest an influence of the environment on the production of anti-IgG. Evidence for the role of an infectious agent was provided by the fact that germ-free @entity7840 /2 were negative in contrast to their SPF relatives. Strains which were positive at @entity428 and @entity7173 for anti-IgG had four-times higher serum levels of total IgA and two-times higher levels of total IgG than the corresponding negative strains from IC and JL. The anti-IgG titers differed markedly from one strain to the other in the same environment; e.g., in @entity19 from @entity428 , BALB/c @entity19 produced 40-times less anti-IgG than 129/Sv. IgA anti-IgG occurred only in high producers of anti-IgG. In these animals, the proportion of IgA vs. IgM anti-IgG was very different from one group to the other; C57BL/6 had mainly IgM anti-IgG, @entity7840 /2 mainly IgA anti-IgG, and 129/Sv both IgM and IgA anti-IgG. The IgA anti-IgG from 129/Sv, 129/J, NZB/BinJ, C57L/J, @entity7840 /2, and C3H/He had restricted hetero-, iso-, and allotypic specificities. It reacted only with mouse IgGa2, but not with the Ig-1b allotype. C57BL/6 also had IgA anti-IgG with a narrow specificity, but directed against @entity6527 without allotypic restriction. In contrast to the specificity of IgA anti-IgG, the antibody activity of IgM anti-IgG was much broader, except in the 129/Sv and 129/J strains where IgM anti-IgG shared the same narrow specificity with IgA.
