CD8+ T Cells Regulate Monopoiesis and Circulating Ly6C-high Monocyte Levels in Atherosclerosis in Mice.


RATIONALE Proinflammatory adaptive immune responses are recognized as major drivers of atherosclerotic lesion formation. Although CD8(+) T cells have recently been proposed as a proatherogenic cell subset, their full scope of actions remains to be elucidated. OBJECTIVE We here addressed the contribution of CD8(+) T cells to monocyte trafficking in atherosclerosis. METHOD AND RESULTS We observed that CD8(+) T cells express proinflammatory cytokines (interferon-γ, tumor necrosis factor-α, and interleukin-12) within atherosclerotic lesions and spleens of high-fat diet-fed low-density lipoprotein receptor-deficient (Ldlr(-/-)) mice. Antibody-mediated CD8(+) T-cell depletion in high-fat diet-fed Ldlr(-/-) mice decreased atherosclerotic plaque formation, associated with decreased macrophage accumulation within lesions. Despite a reduction in vascular chemokine (CC-motif) ligand 2 and chemokine (CXC-motif) ligand 1 expression, CD8(+) T-cell depletion did not directly affect monocyte recruitment to inflamed vessels. However, CD8(+) T-cell depletion decreased chemokine (CC-motif) ligand serum concentrations and circulating Ly6C(high) monocyte counts. We further evidenced that CD8(+) T-cell depletion decreased levels of mature monocytes and myeloid granulocyte-monocyte progenitors in the bone marrow and spleen of hypercholesterolemic mice, effects that were partially reproduced by interferon-γ neutralization, showing a role for interferon-γ. CONCLUSIONS These data suggest that CD8(+) T cells promote atherosclerosis by controlling monopoiesis and circulating monocyte levels, which ultimately contributes to plaque macrophage burden without affecting direct monocyte recruitment, identifying this cell subset as a critical regulator of proatherogenic innate immune cell responses in atherosclerosis.

DOI: 10.1161/CIRCRESAHA.117.304611

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@article{Cochain2015CD8TC, title={CD8+ T Cells Regulate Monopoiesis and Circulating Ly6C-high Monocyte Levels in Atherosclerosis in Mice.}, author={Cl{\'e}ment Cochain and Miriam Koch and Sweena M . Chaudhari and Martin Busch and Jaroslav Pelisek and Louis Boon and Alma Zernecke}, journal={Circulation research}, year={2015}, volume={117 3}, pages={244-53} }