A Specialized CD107a+ Macrophage Subset Drives Selective Mycobacterial Phagocytosis

Eto, C.; Luiz, G.; Silva, H. M.; Munari, E. L.; Mendes, D. A. G. B.; Beck, B. K.; Mascarin, L. Z.; Starick, M.; Canesso, M. C. C.; Reis, B. S.; Silveira, G.; Bordignon, J.; de Menezes, Y. K. T.; Mansur, D. S.; Lummertz da Rocha, E.; Bafica, A. L. B.

doi:10.1101/2025.10.31.685620

bioRxiv · 10.1101/2025.10.31.685620

A Specialized CD107a+ Macrophage Subset Drives Selective Mycobacterial Phagocytosis

Eto, C.·Luiz, G.·Silva, H. M.·Munari, E. L.·Mendes, D. A. G. B.·Beck, B. K.·Mascarin, L. Z.·Starick, M.·Canesso, M. C. C.·Reis, B. S.·Silveira, G.·Bordignon, J.·de Menezes, Y. K. T.·Mansur, D. S.·Lummertz da Rocha, E.·Bafica, A. L. B.

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Abstract

Macrophages are essential for pathogen clearance, yet phagocytic specialization among subsets is poorly defined. Bone marrow-derived macrophages cultured with L929 supernatant or M-CSF separate into FSCloSSCloF4/80loCD11blo (FSCloSSClo) and FSChiSSChiF4/80hiCD11bhi (FSChiSSChi) subsets. Transcriptomic and functional analyses reveal that FSCloSSClo cells possess a hyperphagocytic program driven by enhanced actin cytoskeleton regulators (e.g., Arp2/3) and pro-inflammatory signaling (NF-{kappa}B). These cells excel at internalizing Mycobacterium tuberculosis virulent H37Rv and BCG through actin-mediated, cytochalasin D-sensitive mechanisms. High surface CD107a (LAMP1) expression marks this hyperphagocytic subset and correlates strongly with mycobacterial uptake. FSCloSSClo macrophages produce more TNF and IL-6 upon mycobacterial or TLR2/TLR5 stimulation yet retain IFN-{gamma}-mediated killing capacity. In vivo, CD107a alveolar macrophages in BCG-infected lungs preferentially capture bacilli and upregulate CD195, recapitulating the in vitro phenotype. These findings establish CD107a as a key surface marker of a hyperphagocytic macrophage subset and highlight its role in selective mycobacterial phagocytosis, providing new mechanistic understanding relevant to tuberculosis host defense and therapeutic development. HighlightsO_LIBone marrow-derived FSCloSSCloF4/80loCD11blo macrophage subset excels at M. tuberculosis and BCG uptake C_LIO_LIHyperphagocytic macrophages mount rapid pro-inflammatory TNF/IL-6 responses C_LIO_LICD107a (LAMP1) identifies a pre-existing hyperphagocytic macrophage subset in vitro and in vivo C_LIO_LIBCG infection triggers CD195 (CCR5) upregulation selectively on CD107a alveolar macrophages C_LI

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Eto, C., Luiz, G., Silva, H. M., Munari, E. L., Mendes, D. A. G. B., Beck, B. K., Mascarin, L. Z., Starick, M., Canesso, M. C. C., Reis, B. S., Silveira, G., Bordignon, J., de Menezes, Y. K. T., Mansur, D. S., Lummertz da Rocha, E., Bafica, A. L. B.. 2025-11-02. A Specialized CD107a+ Macrophage Subset Drives Selective Mycobacterial Phagocytosis. https://doi.org/10.1101/2025.10.31.685620

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