Ascites produced in recalcitrant hybridomas by backcrossing to a parental myeloma

Hybridoma lines frequently lose their ability to produce ascites upon extended cultivation in vitro. We have reintroduced genes for tumor formation into three independent hybridoma lines by backcrossing them to the parental myeloma. The parental myeloma cells were eliminated by a brief in vitro selective period in HAT medium, after which the cells were inoculated into pristane-primed mice. In two out of three cases the resultant lines were able to produce ascites without further subcloning or other manipulations. The antibody retained its specificity as judged by immunoblotting. This method is a rapid and efficient approach for the reestablishment of ascites production in hybridoma lines.