Cellular expression of idiotopes defined by monoclonal antibodies

Abstract

Monoclonal anti‐idiotype (Id) antibodies with specificities for determinants related to the antigen‐binding sites of 3 BALB/c myeloma proteins, MOPC‐460, HOPC‐8 and J558, were used to study Id expression on murine lymphocytes. The monoclonal antibodies were shown to react only with Id structures associated with immunoglobulin on B cells. None of these 3 Id nor a V_H Id, detected by a monoclonal antibody made against HOPC‐8 heavy chain, were found on T cells. These Id were detected on splenic B cells in neonatal mice; the frequencies in normal, nude and germ‐free mice were similar: MOPC‐460 Id⁺: 1.05 ± 1.7/10⁴ spleen cells, HOPC‐8 Id⁺: 1.45 ± 1.2/10⁴ and J558: 0.35 ± 0.6/10⁴. Almost all Id⁺ cells bore surface IgM, a few expressed surface IgG. MOPC‐460 Id⁺ IgG⁺ cells were mainly γ_2a⁺ or γ_2b⁺, whereas J558 and HOPC‐8 Id⁺ IgG⁺ cells were γ₃⁺.