Preparation and subfractionation of isologous and heterologous anti-idiotypes, using FV fragments.

Fv fragments prepared from the BALB/c anti-dinitrophenyl (DNP) myeloma proteins, produced by plasmacytoma MOPC 315 and XRPC 25, were used to raise anti-idiotypic antibodies in rabbits. Anti-idiotypes to these proteins were also prepared in the syngeneic BALB/c mice by injecting the intact proteins, whereas Fv fragment failed to induce antibodies in these mice. Rabbit anti-Fv of late bleedings did not show the presence of antibodies to "framework determinants" (determinants common to all V regions of mouse immunoglobulins), and they contained precipitating anti-idiotypes whereas mouse antisera contained non-precipitating anti-idiotypes. No cross-reaction was observed between anti-idiotypes to these myeloma proteins and induced anti-DNP antibodies from BALB/c mice, when either rabbit or mouse antisera were analyzed. The anti-sera were fractionated into anti-binding site and anti-non-binding site by adsorption onto the immunogen-Sepharose column and elution by DNP lysine, followed by elution with acetic acid. Only the anti-binding sites were inhibited by hapten in their interaction with the homologous myeloma protein. The rabbit anti-Fv antibodies were predominantly (over 90%) anti-non-binding site whereas the mouse anti-idiotypes were predominantly (60 to 70%) anti-binding site.