[Utilization of particulate and immuno-modulating adjuvants for enhancement of immune response against tumors antigenic markers]

ABSTRACT

Regards to the weak immunigenicity of tumor cells as well as recombinant antigenic markers [like BLP25], adjuvants are needed for enhancement of immune response and it's skewing toward cellular immunity. In this research poly [lactide-co-glycolide] [PLGA] microspheres were used as delivery system for a recombinant mucin named mucin 1 [MUCl, BLP25] as a recombinant antigenic cancer marker, and CpG-ODN was used for enhancement of immune response and its biasing toward cellular immunity. PLGA microspheres encapsulated with BLP25 and CpG-ODN were prepared using a w/o/w emulsion method. Encapsulation of BLP25 was determined by a HPLC method and spectrophotometry at 260 nm was used for quantification of encapsulated CpG-ODN. In vivo immunization studies were performed by SC injections of 20 micro g BLP25 and 4 micro g CpG-ODN in mice [4 animal per group]. Group I] Mice immunized with microspheres co-encapsulated with BLP25 and CpG; Group II] Mice immunized with microspheres encapsulated with BLP25 mixed with CpG solution; Group III] Mice immunized with microspheres encapsulated with BLP25. For evaluation of specify of immune response, T lymphocytes separated from different groups of mice were incubated with different antigens [T Cell Proliferation Assay]. IFN-gamma and IL-4 cytokines were assayed by a sandwich ELISA method. T lymphocytes separated from group I, showed high proliferation [stimulation index = 25] and high levels of IFN-y interferon [11200+/-172 pg/ml] which were significantly higher than other two groups [P<0.0001]. Co-encapsulation and co-delivery of MUCl and CpG-ODN produced high cellular [Thl] immunity responses [high levels of IFN-gamma and no IL-4], indicating the high adjuvanticity potential of CpG-ODN for immunization against cancer markers. Importance of co-encapsulation of antigen and adjuvant in the same delivery system for better adjuvant effect was also approved