CHARACTERIZATION OF PUTATIVE MONOCLONAL ANTI-G3M(U) AND ANTI-G3M(G) REAGENTS AND THEIR ANTIGENIC DETERMINANTS

Monoclonal antibodies (MAbs) against IgG3 allotypic markers were evalu ated in haemagglutination inhibition and IgG3 capture ELISA. MAbs PNF6 9C and 200D1 exhibited G3m(u) and G3m(g) specificity respectively. In HAI target epitopes detected by MAbs were remarkably stable to physioc hemical degradation. Western blotting revealed that MAb 200D1, bound t o intact IgG3 heavy chain disease protein and not its pFc' fragment; a result consistent with the CH2 domain location of the G3m(g) allotope . The G3m(u) allotope is also located within this domain. Suprisingly anti-G3m(u) MAb PNF69C bound to the pFc' of IgG3-related protein, HW, and to the pFc' of IgG1-related protein, PR, in Western blot.