Elicitation of distinct populations of monoclonal antibodies specific for the variable domains of monoclonal anti-fluorescein antibody 4-4-20.

Armenian hamsters were immunized with non-liganded, partially liganded or affinity-labeled anti-fluorescein Mab 4-4-20. Seventeen hybridoma producing monoclonal anti-4-4-20 antibodies were characterized from chemically-mediated fusions of immune hamster lymphocytes with murine Sp2/O-Ag14 myeloma cells. Distinct populations of anti-4-4-20 monoclonal antibodies were isolated from hamsters receiving immunizations with partially liganded Mab 4-4-20 relative to those receiving affinity-labeled 4-4-20. Two of the three monoclonal antibodies produced in response to partially liganded 4-4-20 were inhibited in their interaction with 4-4-20 by fluorescyl ligand. These two clones, 1F4 and 1B7, recognized unique epitopes on the 4-4-20 molecules, as demonstrated by non-reactivity with members of the 4-4-20 idiotype family. Additionally, 1F4 and 1B7 demonstrated the ability to delay the association of fluorescein with Mab 4-4-20. The 14 characterized non-ligand-inhibitable Mabs elicited to affinity-labeled 4-4-20 were classified into four separate groups based on various binding properties with members of the 4-4-20 idiotype family and binding to resolved H- and L-chains in a western blot. Members of three of the four groups showed strong reactivity with both 04-01 Ig and 04-01 SCA, which utilizes the same L-chain as Mab 4-4-20. Six non-ligand-inhibitable Mabs, 4A6, P1E11, 3A5-1, 2C3, 2C4, and 1A4, delayed the dissociation rate of ligand from Mab 4-4-20 and mutant 4-4-20 SCA L32phe.