Early innate role for CD8αα+ cells in tuberculosis

Abstract

Cell types that mediate early control of Mycobacterium tuberculosis (Mtb) infection are not well understood. Winchell and Nyquist et al. (https://doi.org/10.1084/jem.20230707) show that CD8αα+ lymphocytes have a major role in the innate suppression of Mtb growth in the lungs of macaques.

Insights from Daniel L. Barber.

CD8⁺ cells have a major role in the early response to Mtb infection. Depletion of all CD8⁺ cells by administration of CD8α-depleting antibodies prior to Mtb infection results in higher take of the inoculated bacteria, much larger numbers of pulmonary granulomas, higher bacterial loads in the chest, and greater dissemination of bacteria into extrapulmonary tissues. This cannot be due to the activity of conventional CD8 T cells, as preferentially depleting CD8β⁺ cells had much less of an impact on the infection in this time frame. Thus, one or more populations of innate cells or innate-like T cells has a major role in the suppression of Mtb growth at the earliest stages of infection. Figure made with BioRender.