Mechanisms in the in vivo release of lymphokines: relationship of high and low responsiveness to other parameters of the immune response.

Variations exist between different strains of inbred mice in the release of lymphokines into the circulation. A number of manifestations of cell-mediated immunity in mice sensitized intravenously with Mycobacterium bovis BCG were analyzed to determine their association with the in vivo release of gamma interferon (IFN-gamma) and migration inhibitory factor. Differences occurred among the strains in the proliferative responses of splenic cells to specific antigen and in the release of IFN after the challenge of BCG-sensitized mice with lipopolysaccharide. However, the capacity of an individual strain to release migration inhibitory factor and IFN-gamma into the circulation did not parallel the extent either of the proliferative responses or of the release of IFN induced by lipopolysaccharide. Not all of the strains developed marked delayed footpad reactions to challenge with PPD regardless of the extent of their responses by other parameters. Delayed footpad reactions did develop in mice sensitized via the subcutaneous route, although this sensitization did not result in the capacity to release migration inhibitory factor and IFN-gamma into the circulation of individual inbred strains.