Pro-inflammatory CD4+ T helper (Th) cells drive the pathogenesis of many autoimmune conditions. Recent advances have modified views of the phenotype of pro-inflammatory Th cells in autoimmunity, extending the breadth of known Th cell subsets that operate as drivers of these responses. Heterogeneity and plasticity within Th1 and Th17 cells, and the discovery of subsets of Th cells dedicated to production of other pro-inflammatory cytokines such as GM-CSF have led to these advances. Here, we review recent progress in this area and focus specifically upon evidence for chemokine receptors that drive recruitment of these various pro-inflammatory Th cell subsets to sites of autoimmune inflammation in the CNS. We discuss expression of specific chemokine receptors by subsets of pro-inflammatory Th cells and highlight which receptors may be tractable targets of therapeutic interventions to limit pathogenic Th cell recruitment in autoimmunity.

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Type I regulatory (Tr1) cells contribute to immune suppression in the context of chronic infection, autoimmunity, and transplant tolerance. However, their physiological relevance in the resolution of acute respiratory infection is not understood. Here, we identify Tr1 cells accumulating in the lung parenchyma during resolution of the response to sublethal influenza A virus infection in mice. Tr1 cells were dependent on IL-27Ra; and in their absence recovery from IAV-induced weight loss is impaired. Notably, these Tr1 cells did not necessarily co-express the typical Tr1 markers LAG-3 and CD49b, with four distinct populations of Tr1 cells apparent in the lungs. Each population was suppressive and were differentially dependent on IL-10 to mediate suppression. Transcriptional analysis revealed a core Tr1 gene signature in each population and distinct expression profiles indicative of different states of activation and differentiation. Finally, sort-transfer experiments indicated non-linear plasticity between these subsets of Tr1 cells. Together, these data support Tr1 cells contributing to the resolution of acute inflammation and define novel Tr1 cell phenotypes in acute infection.