Loss of antibody production accompanied by chromosome loss in a cloned hybrid line secreting antibodies to sheep red blood cells.

Somatic cell hybrids between Sp2/O-Ag14 mouse myeloma cells and lymphocytes derived from BALB/c mice hyperimmunized with sheep red blood cells (SRBC) were produced. One hybrid producing IgG1 antibody to SRBC was selected, cloned twice and subsequently transferred to BALB/c mice. After a number of transfers it was found that the antibody titer in ascites fluid gradually decreased. Cytogenetic analysis revealed gradual chromosome loss in the hybrid clone, which produced progressively less antibody.