AFFINITY COLUMNS CONTAINING ANTI-DNA ID-GLOBULIN( HUMAN MYELOMA PROTEINS ADSORB HUMAN EPIBODIES FROM INTRAVENOUS GAMMA)

Objective. To study eluates of intravenous gamma globulin (IVGG) prepa red from affinity columns of human cationic IgG myeloma proteins beari ng anti-DNA idiotype (Id) markers 16/6, F4, 3I, and 8.12 for possible anti-Id (combining site) blocking activity. Methods. Anti-DNA idiotypi c antibody activity was studied in 3 preparations of IVGG containing h igh, medium, and low levels of IgG anti-F(ab')(2), and in 4 other comm ercial IVGG preparations, Affinity-purified IgG anti-DNA (APAD) from s ystemic lupus erythematosus (SLE) patients was biotinylated, and bindi ng to DNA coated on enzyme-linked immunosorbent assay plates was used to measure anti-DNA antibody activity, IVGG was adsorbed to Sepharose 4B affinity columns linked to a panel of cationic human IgG myeloma pr oteins positive for anti-DNA Id markers 16/6, F4, 3I, and 8.12, Materi al adsorbing to such columns was eluted at low pH (2.5) and after neut ralization, tested for its ability to inhibit biotinylated APAD reacti ng with DNA. Results. Only 0.05-0.9% of IVGGs bound firmly to Id affin ity columns, These IVGGs were then eluted, using pH 2.5 glycine-saline and eluates neutralized to pH 7.4, Column flowthrough and eluate frac tions were compared for their ability to block SLE APAD reacting with DNA, Significant inhibition of SLE APAD combining sites was observed w ith eluates from anti-DNA Id affinity columns; however, no correlation between IVGG anti-F(ab')(2) activity and true anti-Id blocking of APA D was apparent, No residual anti-id activity remained in column flowth rough fractions, No anti-Id blocking activity was recorded for IVGG el uates from human cationic myeloma columns devoid of the 4 anti-DNA Id markers, DNase treatment of IVGG or Id column eluates did not affect a nti-Id blocking activity, Thus, all detectable anti-DNA idiotypic anti body capable of blocking SLE anti-DNA combining sites bound to Id+ aff inity columns, Column eluates also showed some relative concentration of IgG anti-DNA activity, which was of lower affinity for DNA than ant ibodies also present in eluates which blocked anti-DNA combining sites . Conclusion. The presence of both anti-DNA and antiidiotypic (anti-co mbining site) activity in human anti-DNA Id column eluates indicates t hat epibodies from IVGG are relatively concentrated when this strategy is used, This approach may lead to a new strategy for treatment of SL E nephritis.