CHARACTERIZATION OF A UNIQUE ANTI-DNA HYBRIDOMA

We have previously described the isolation and in vitro binding proper ties of eight anti-DNA monoclonal antibodies (MAbs) from an MRL-lpr mo use, In light of recent reports that have indicated it is possible to isolate multiple MAbs from a single hybridoma, our pathogenic hybridom a, 11F8, was examined for evidence of similar phenomena, Chromosome co unting suggested that 11F8 cells are unusual and might indeed be expre ssing multiple heavy and/or light chains, PCR, cloning, and sequencing of immunoglobulin heavy and light chains indicate that 11F8 displays expression of both gamma 2a and gamma 3 heavy chains at the DNA level, Flow cytometry and amino acid sequencing reveals that expression of m ultiple isotypes also occurs at the protein level but only a single he avy-and light-chain sequence is able to bind DNA, Based on these resul ts, we conclude that 11F8 is an unusual hybridoma that secretes two di stinct heavy and at least one light chain from a single cell, and may represent a trioma, a stable three-cell fusion.