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

The molecular mechanisms leading to the establishment of immunological memory are inadequately understood, limiting the development of effective vaccines and durable anti-tumor immune therapies. Here we show that ectopic OCA-B expression is sufficient to improve antiviral memory recall responses, while having minimal effects on primary effector responses. At peak viral response short lived effector T cell populations are expanded but show increased Gadd45b and Socs2 expression, while memory precursor effector cells show increased expression of Bcl2 , Il7r and Tcf7 on a per-cell basis. Using an OCA-B mCherry reporter mouse line, we observe high OCA-B expression in CD4 + T CM cells. We show that early in viral infection, endogenously elevated OCA-B expression prospectively identifies memory precursor cells with increased survival capability and memory recall potential. Cumulatively, the results demonstrate that OCA-B is both necessary and sufficient to promote CD4 T cell memory in vivo and can be used to prospectively identify memory precursor cells. Significance CD4 + T cell memory is incompletely defined and memory progenitors difficult to identify. Here, we show that expression of the OCA-B transcription coactivator in CD4 + T cells is necessary and sufficient to drive productive memory. Using a novel mCherry reporter mouse line, we show that OCA-B expression enriches for responding effector cells with elevated memory potential. The results show that OCA-B expression in T cells is sufficient to promote CD4 + memory formation and marks memory precursor cells.