Fine specificity of antibodies to poly(Glu60Ala30Tyr10) produced by hybrid cell lines.

The polyethylene glycol-mediated cell fusion technique has been used to analyze the diversity of the antibody response to the terpolymer poly(Glu60Ala30Tyr10)(GAT). Nine stable clones (all producing IgM K anti-GAT antibodies) were isolated from a fusion between P3-X63-Ag8 myeloma cells and spleen cells from a DBA/2 mouse sensitized to GAT 5 days earlier. Seven other clones (producing IgG K anti-GAT antibodies) were derived from another fusion between NSI myeloma cells and spleen cells of (C57BL/6 X DBA/2)F1 hybrid mice hyperimmunized with GAT. These 16 anti-GAT antibodies were grouped according to their pattern of reactivity with GAT and the two related polymers of poly(Glu60Ala40) (GA) and poly(GLU50Tyr50) (GT). Two monoclonal anti-GAT antibodies (IgM F9-102.2 and IgG F17-148.3) demonstrated crossreactivity with GA but failed to crossreact with GT determinants. In contrast, the remaining 14 hybridoma antibodies demonstrated preferential reactivity with GAT but also exhibited crossreactive binding to GT and in some cases GA. There was a correlation between the fine specificity pattern and the presence of a common anti-GAT idiotype on these antibodies. Thus, the hybridoma anti-GAT antibodies which reacted with GT shared crossreactive idiotypic determinants (CGAT) present in mouse anti-GAT immune sera. In contrast, the monoclonal F9-102.2 and F17-148.3 antibodies that failed to bind to GT lacked the major CGAT idiotypic determinants.