| Abstrakt: |
Previous reports described the properties of a high affinity (Ka= 1.7×1010M−1) prototype anti-fluorescein monoclonal antibody 4-4–20, an intermediate affinity (Ka= 3.7×107M−1) prototype 9–40, and Ig members of the 9–40 idiotype family (comprised of 3–24, 5–14, 5–27, 10–25 and 12–40). Although the seven monoclonal anti-fluorescein antibodies expressed similar active site structural determinants (idiotypes) as determined serologically, each was characterized by different affinities for fluorescein and fine specificity binding patterns. Partial heavy (H)- and light (L)-chain N-terminal amino acid sequence analyses revealed all antibodies (except 5–27) were composed of highly homologous VHIII(C) and VκII subgroup genes, respectively. Antibody 5–27 utilized a VHIII(B) and a VκV subgroup genes and shared low V-region sequence homology with 4-4–20, 9–40 and the remaining 9–40 idiotype family. In addition, complete 4-4–20, VH- and VL-region primary structures were determined to better understand antibody-antigen interactions. Antibody 4-4–20 utilized a VHIII(C) subgroup VH-gene, a truncated Sp2D gene segment, JH4, a VκII subgroup VL-gene, and Jκ1. Antibody 4-4–20 VHand VLcomplementarity-determining regions contained many basic and aromatic amino acid residues capable of interaction with fluorescein. Results are discussed in terms of idiotypic and fluorescein-binding characteristics as well as antibody structural and functional diversity in the immune response. |
