Use of encapsulated single chain antibodies for induction of anti-idiotypic humoral and cellular immune responses

The use of biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres as a cancer vaccine delivery system for induction of anti-idiotypic responses has been investigated using a single chain antibody scFv-pDL10, which recognizes the human ovarian cancer antigen CA125. Immunization of mice with scFv-pDL10 encapsulated in PLGA microspheres resulted in enhanced humoral and cellular immune responses when compared to scFv-pDL10 alone. Induced anti-idiotypic antibodies (Ab2) which mimic the original antigen CA125 compete with CA125 for the epitope. A cellular response (T2 induction) was also observed. These results raise the possibility of anti-idiotypic antibody induction by a single chain antibody, encapsulated in biodegradeble microspheres, as a potential vaccine for ovarian carcinoma.