OCA-B/Pou2af1 is sufficient to promote CD4+ T cell memory and prospectively identifies memory precursors

Transcriptional co-regulator OCA-B/Pou2af1 restricts Th2 differentiation

Background

Type 2 immunity is initiated through a synergistic response between innate and adaptive immune cells to facilitate host-pathogen defense and wound repair, yet aberrant responses can contribute to chronic inflammation and allergic disease. CD4+ type 2 helper T (Th2) cells facilitate the adaptive immune response through the secretion of cytokines such as IL-4, IL-5, and IL-13. While the Th2 program is governed by the transcription factor GATA3, less is known about regulators that fine-tune the Th2 cytokine response.

Method

We used a proximity labeling system to map proteins associated with the transcriptional co-regulator OCA-B, encoded by Pou2af1, in T cells. We used a series of genomic, biochemical and immunological assays to probe the interaction with one particular hit from the screen.

Results

We find that OCA-B indirectly associates with GATA3. ChIP-seq analysis reveals coenrichment of Gata3 and the transcription factor Oct1, a partner protein of OCA-B, at genomic locations responsible for the Th2 program including Il4, Il13, Il5, Gata3, and Irf4. DNA binding data using recombinant proteins and reporter data using T cell lines are consistent with a model in which OCA-B restricts transcription at the Th2 locus control region and subsequent IL-4 and IL-13 secretion. Finally, in an in vivo papain allergy model we show OCA-B expression in T cells limits the frequency of T cells within the lung.

Conclusion

These findings shown that OCA-B helps restrict Th2 function at least in part through communication with GATA3.

OCA-B promotes pathogenic maturation of stem-like CD4 + T cells and autoimmune demyelination

Stem-like T cells selectively contribute to autoimmunity, but the activities that promote their pathogenicity are incompletely understood. Here, we identify the transcription coregulator OCA-B as a driver of the pathogenic maturation of stem-like CD4 + T cell to promote autoimmune demyelination. Using two human multiple sclerosis (MS) datasets, we show that POU2AF1 , the gene encoding OCA-B, is elevated in CD4 + T cells from MS patients. We show that T cell-intrinsic OCA-B loss protects mice from experimental autoimmune encephalomyelitis (EAE) while preserving responses to viral CNS infection. In EAE models driven by antigen reencounter, OCA-B deletion nearly eliminates CNS infiltration, proinflammatory cytokine production and clinical disease. OCA-B-expressing CD4 + T cells of mice primed with autoantigen express an encephalitogenic gene program and preferentially confer disease. In a relapsing-remitting EAE model, OCA-B loss protects mice specifically at relapse. During remission, OCA-B promotes the expression of Tcf7 , Slamf6 , and Sell in proliferating CNS T cell populations. At relapse timepoints, OCA-B loss results in both the accumulation of an immunomodulatory CD4 + T cell population expressing Ccr9 and Bach2 , and loss of pro-inflammatory gene expression from Th17 cells. These results identify OCA-B as a driver of pathogenic CD4 + T cells.