Our recent advances in the use of fluorescent fitness reporter Mtb strains in the murine TB model has afforded us a unique appreciation of the role of macrophage lineages in both the control and promotion of Mtb growth. Moreover, the extension of these observations through the successful development of Dual RNA-seq protocols for characterization of infected cells isolated directly from the murine lung has provided a further understanding of how host nutritional immunity is central to the control of bacterial growth, at least in early infection.

We propose building on our collaboration with Dr. Henry Mwandumba in Malawi and extending these observations through an ex vivo Mtb challenge model with human bronchoalveolar lavage (BAL) cells to functionally phenotype the macrophage lineages present in the human lung airways. Furthermore, we recently demonstrated the persistence of transcriptionally-active HIV-1 genomes in the alveolar macrophages of ARTnaïve and ART-suppressed donors in Malawi and believe that we can take advantage of this unique human subjects cohort to characterize the impairment of lung immunity known to occur in people living with HIV-1 that renders them hypersusceptible to both TB and other lower respiratory tract infections. Our hypothesis is that the functional and phenotypic typing of Mtb-infected human lung macrophage subsets from healthy and HIV-1-infected volunteers will generate testable models for immune-mediated control of Mtb growth that will inform future vaccine development programs.