EFFECT OF IMMUNITY INDUCED BY CO-IMMUNIZATION OF mtb8.4 GENETIC VACCINE WITH SIGNAL SEQUENCE AND HUMAN INTERLEUKIN 12

[Objective]To observe the specific celluar immune response in mice induced by co-immunization of DNA vaccine of Mtb8.4 with signal sequence(MS)and plasmid encoding human interleukin 12(hIL-12).[Methods]Fifteen C57BL/6N mice were divided into following groups:MS gene vaccine plus plasmid of hIL-12,MS gene vaccine,BCG,vacant vector alone and PBS.Mice were immunized intramuscularly in both hind limbs three times at the intervals of three weeks or once subcutaneously with 1×106 of viable M.bovis BCG Pasteur at the time of the first DNA immunization.The level of IFN-γ in supernatant of spleno-lymphocyte cultures were measured by ELISA methods.CTL activities of spleno-lymphocyte were detected with LDH release assay.[Results]The levels of IFN-γ and IL-2 in supernatant of spleno-lymphocyte cultures in the group of MS gene vaccine plus plasmid of hIL-12 were significantly higher than group of MS alone(P﹤0.01)and were same as BCG group,the level of IL-4 was lower than BCG group(P﹤0.01).CTL activity of spleno-lymphocyte in the co-immunization group was stronger than other groups.[Conclusion]Co-immunization of MS gene vaccine and plasmid encoding human interleukin 12 can enhance the specific cellular immune response induced by the MS gene vaccine alone.