Culture of sheep X mouse hybridoma cells in vitro

Hybridomas were made between NS1/1-Ag4-1 mouse myeloma cells and spleen and lymph node cells from a sheep immunized with sheep red cells (RBC). The hybrid colonies grew well in culture but there was a substantial loss of sheep chromosomes. No hemolytic or agglutinating antibodies were detected in the culture supernatants after the 17th day following fusion, but immunofluorescence tests indicated that a few of the cells may have been expressing sheep IgG. Cytogenetic comparison of cells grown with and without HAT medium provided evidence that the enzyme HGPRT is located on the X chromosome of sheep as it is in man and mouse. Hybridoma isozyme patterns of esterase, G6PD, 6PGD, NP, LDH and SOD tested between the 63rd and 71st day of culture were like those of NS1; NP and LDH also showed zones that probably came from the sheep component.