Recombinant vaccinia viruses expressing interleukin-5 stimulate an earlier appearance of antibody-secreting cells in the lung.

Interleukin-5 (IL-5) is a cytokine that participates in the regulation of antibody secretion, in particular promoting the secretion of IgA at mucosal sites. In this report, recombinant vaccinia viruses expressing IL-5 have been inoculated into mice and the appearance of antibody-secreting cells in the spleen and lungs investigated. Although vaccinia virus-expressed IL-5 did not increase the level of IgA in serum, antibody-secreting cells, measured in an enzyme-linked immunosorbent spot assay, appeared earlier in lungs when the immunizing virus expressed IL-5. These early B cells secreted either IgM or IgG1.