A Nonadjuvanted IgG2a Monoclonal Antibody against Nucleosomes Elicits Potent T Cell-Dependent, Idiotype-Specific IgG1 Responses and Glomerular IgG1/IgG2a Deposits in Normal Mice.

Idiotypes (Ids) are unique epitopes of Ab V regions and can trigger anti-Id immune responses, but immunization with several nonadjuvanted isologous IgG mAbs has induced tolerance to their Ids. We immunized non-lupus-prone mice with 11 allotype "a" of IgG2a (IgG2a) and 4 IgG2c nonadjuvanted, isologous mAbs purified from serum-free medium. Of five IgG2a mAbs with specificity for nucleosomes, the repeating histone-DNA subunit of chromatin, four elicited an IgG1 anti-mAb response and one mAb was nonimmunogenic.

The MHC haplotype H2b converts two pure nonlupus mouse strains to producers of antinuclear antibodies.

Studies of mouse lupus models have linked the MHC H2(b) haplotype with the earlier appearance of antinuclear autoantibodies and the worsening of nephritis. However, it is unknown whether H2(b) by itself, in the context of pure nonlupus strains, is "silent" or sufficient with regard to loss of tolerance to chromatin (nucleosomes). In this study we show that, beginning approximately 6-9 mo of age, H2(b)-congenic BALB/c (denoted BALB.

Immunoglobulin heavy chain constant regions regulate immunity and tolerance to idiotypes of antibody variable regions.

Particular syngeneic adjuvant-free monoclonal antibodies are immunogenic and elicit antibody responses against the variable region idiotypes (Ids). We here study how heavy-chain constant regions (C(H)) regulate immune responses to Ids of free, uncomplexed monoclonal antibodies. To this end, we selected two hybridomas, called Id(3) and Id(A.