In order to assess the nature of the T cells recruited to the site of infection, FP granuloma lymphocyte populations from each strain were stimulated with various M. leprae crude and purified antigens in vitro and evaluated by flow cytometry for IFN-γ production by CD4+CD44+ (Fig. 6) and CD8+CD44+ (Fig. 7) cells. The gene discussed is CD4; the disease is infection.