Identification of recurrent idiotypes within the unrestricted anti-fluorescein immune response.

The BALB/cV immune response to fluorescein (F1) was analyzed for expression of serologically defined idiotypes (Id) present on two anti-F1 hybridoma proteins, 3-13 and 3-17. After a I degree, II degree, or III degree immunization with F1-KLH, Id 3-13 and 3-17 were expressed in 15 of 28 and 22 of 28 mice, respectively. Solid-phase Id inhibition assays, performed by using pooled or individual anti-F1 antibody, indicated Id 3-13 and 3-17 represented less than 1.0% of the I degree, II degree, or III degree serum anti-F1 repertoire. Hybridoma proteins 3-13 and 3-17 had similar but distinct active sites as indicated by similar patterns of Id inhibition, fine specificity of binding, and affinity for F1. Analyses of 11 anti-F1-AECM-Ficoll hybridoma proteins (predominantly mu, lambda) indicated 4 of 11 clones were weakly cross-reactive with 3-13 and 3-17. Anti-F1-KLH II degree antibody from mice of various Igh allotypes was also screened and indicated these Id were expressed in each strain but at lower levels than in BALB/cV mice and were not strictly allotype associated. Id 3-13 and 3-17 represent the first demonstration of repertoire-specific recurrent Id expressed during a T-dependent immune response lacking a dominant Id.