The rates of bacterial growth for thetwo strains were indistinguishable prior to day 14 post infection (Figure 4F), indicating thatexpression of fbpB by the hspX promoter doesnot attenuate M. tuberculosis in vivo during the innate immunestage of infection, prior to recruitment of CD4+ effector Tcells to the lungs. The gene discussed is CD4; the disease is infection.