Karyotype analysis of hybridomas producing monoclonal antibodies against different antigens

On the basis of karyotype analysis of the 6 groups of mouse--mouse hybridomas secreting monoclonal antibodies against 5 different antigens we found: (1) The karyotypic variability of clones in all six compared groups of hybridomas was consistent and was influenced neither by the specificity of secreted monoclonal antibodies nor by the character of antigen used for immunization (soluble or particulate). (2) The faster growing hybridomas had a lower mean chromosome number than the slower proliferating clones of the same origin. (3) Karyotypes of subclones isolated from ascites fluid of a mouse inoculated i.p. with clones permanently growing in vitro included a markedly higher mean chromosome number than the karyotypes of originally inoculated hybridoma cells.