Isolation of IgG1-secreting switch variants from IgM hybridomas produced after in vitro immunization

IgG1-secreting variants have been isolated from three different IgM-secreting hybridomas, in two instances following in vitro immunization. The method used was based on sequential sublining in combination with selection by an IgG1-specific two-site ELISA system employing two different IgG1-specific polyclonal antisera. Idiotypic identity between the IgG1 variants and their respective IgM parent was demonstrated using syngeneic anti-idiotypic antisera. The antigen binding specificity in the IgG1 variants was also conserved. Isolation of naturally occurring IgG1 switch variants from IgM-secreting hybridomas that are produced after in vivo immunization offers a solution to the major disadvantages associated with the generation of IgM hybridomas.