Macrophage Migration Inhibition Studies with Cells from Mice Vaccinated with Cell Walls of Mycobacterium bovis BCG: Relationship Between Inhibitory Activity of Lung Cells and Resistance to Airborne Challenge with Mycobacterium tuberculosis H37Rv.

In an effort to evaluate the role of delayed hypersensitivity in acquired resistance of mice to airborne infection with Mycobacterium tuberculosis H37Rv, the ability of lung and peritoneal cells from mice vaccinated in various ways with mycobacterial fractions or with M. bovis BCG to inhibit, in the presence of purified protein derivative, in vitro migration of normal peritoneal cells was determined. The degree of inhibition induced by lung cells was correlated with immunity, but that induced by peritoneal cells could not be associated with enhanced resistance. Live BCG given intravenously to mice stimulated greater resistance to infection and inhibitory activity of lung cells than did live BCG given subcutaneously. Vaccines with a protective index greater than 1 also induced a significant increase in lung weight. Although a correlation between ability of lung cells to inhibit cell migration and acquired resistance of the host to airborne infection with H37Rv was demonstrated, the data do not exclude the possibility that the two phenomena are independent responses to the immunologically complex mycobacterial antigens.