Isolation and characterization of a mouse-rabbit hybridoma

Immunoglobulin was obtained from a hybridoma cell line, which was a reclone of a hybrid between a rabbit cell and mouse myeloma cell (X63-Ag8). The immunoglobulin, isolated from the cell culture medium was found to be homogeneous by isoelectrofocusing and immunoelectrophoresis and consisted of mouse heavy and rabbit light chains, linked by disulphide bonds. All immunoglobulin molecules carried both mouse and rabbit determinants; mouse determinants were associated only with the heavy chains while rabbit determinants were only associated with the light chains. The rabbit light chains were of Ab4 allotypical specificity, but possess only some of the Ab4 determinants normally present in Ab4/Ab4 animals. It was suggested that the restriction in allotypical specificity may be a general property of light chain Ab allotypes; the normal serum immunoglobulins may be heterogeneous with respect to the allotypic determinants and any one molecule may possess only a proportion of determinants detected by a conventional anti-allotype antiserum.