CD4 T cell help is essential for the development of bT_RM in response to VSV infection.

(A) Frequency of D^bLT359 tetramer⁺ CD8 T cells from brains 30 days post-VSV infection. (B) Frequency of CD103⁺ D^bLT359 tetramer⁺ CD8 T cells from brains 30 days post-VSV infection. (C) gMFI of PD-1 expression on D^bLT359 tetramer⁺ CD8 T cells. (D) Number of D^bLT359 tetramer⁺ CD8 T cells from brains 30 days post-VSV infection. Mean ± SD of 3–4 mice per group from 2 independent experiments. *P<0.05, **P<0.01, Mann-Whitney test (A-C) and one-way ANOVA (D).