ENHANCEMENT OF MUCOSAL IGA RESPONSES BY INTERLEUKIN-5 AND INTERLEUKIN-6 ENCODED IN RECOMBINANT VACCINE VECTORS

The expression of the genes for murine interleukin-5 (IL-5) or IL-6 in recombinant vaccinia virus vectors markedly increased IgA reactivity to cc-expressed heterologous antigen in the lungs of mice inoculated i ntranasally with the viruses. These elevated local IgA responses reach ed a peak four times higher than those elicited by control viruses 14 days after infection and these peak levels were maintained for at leas t four weeks. Elevated IgA responses, reaching a peak 3-4 weeks after immunization, were also observed in the lungs of mice inoculated with IL-6 expressed by another vector, fowlpox virus. The results indicate that these factors enhance the development of mucosal IgA reactivity i n vivo and suggest that their expression in mucosal vaccine vectors ma y stimulate local immune responses. The approach described in this stu dy may be useful in stimulating mucosal immunity to a wide range of ve ctor-encoded antigens, not only for vaccination against disease but al so for immunocontraception by the co-expression of antigens involved i n reproduction.