Primary structures of three Armenian hamster monoclonal antibodies specific for idiotopes and metatopes of the monoclonal anti-fluorescein antibody 4-4-20.

This paper reports the complete V gamma, V kappa, C gamma 1 and C kappa nucleotide and deduced amino acid sequences of two hamster monoclonal anti-metatype antibodies, 3A5-1 and 4A6. These antibodies have been previously characterized in terms of their binding and molecular stabilization properties with liganded murine monoclonal and single-chain antibody 4-4-20 active sites. Also reported are the complete V kappa and C kappa nucleotide and deduced amino acid sequence of hamster monoclonal anti-idiotype antibody 1F4, which is specific for the unliganded 4-4-20 active site. Oligonucleotide primers based on the 5' ends of murine variable genes, along with primers specific for murine IgG C gamma 1 and kappa constant region genes, have been used in cDNA and polymerase chain reactions (PCRs) to amplify IgG cDNA from Armenian hamster/mouse hybridomas. The hamster C gamma 1 and C kappa domain sequences are highly homologous to previously reported murine sequences. The anti-idiotype mAb V kappa gene demonstrated strong similarity to the murine V kappa V gene subgroup while the two anti-metatype mAb V kappa genes approximated more closely to the murine V kappa III gene subgroup. The two anti-metatype mAbs utilized highly homologous V gamma genes, with differing HCDR 3 regions, that appeared similar to the murine V gamma I(a) subgroup. These sequence determinations represent the first primary structures reported for antibodies with anti-metatype activity and are additions to the relatively sparse hamster immunoglobulin genetic database. Results are discussed in terms of 4-4-20 active site specificity and anti-metatype activity, as well as immunoglobulin structural diversity in an anti-Ig immune response.