Specific bovine monoclonal antibody produced by a re-fused mouse/calf hybridoma

Hybridomas made by fusing NSO (subline NSI Ag 4-1) mouse myeloma cells with lymph node cells from a calf immunized with sheep red blood cells failed to maintain antibody secretion in culture. However, when two of these hybridomas were selected in 8-azaguanine and then re-fused with immunized calf lymph node cells, several lines were obtained that secreted bovine Ig. One cloned line, producing bovine IgG1 (strongly lytic in the presence of rabbit complement and presumed to be an anti-Forssman) was maintained in culture for five months. Cytogenetic studies confirmed that the mouse/calf hybridomas lost bovine chromosomes as they proliferated, but that re-fusion increased the bovine complement from a mean of 5 (2 n) to 11 (2 n) bovine chromosomes per cell. It is proposed that the selected hybridoma lines may be suitable fusion partners for the production of further monoclonal bovine antibodies.