FIG 3.

CD8⁺ T resident memory cells are abundant in the CNS during long-term infection and maintain an effector phenotype. (A) Lymphocytes were purified from whole-brain single-cell suspensions of perfused mice at the indicated days postinfection and subjected to flow cytometric analysis. Black bars, total numbers of CD3⁺ CD8⁺ T cells; white bars, total numbers of CD3⁺ CD8⁺ CD103⁺ T cells. #, P < 0.05, Mann-Whitney U test for the proportion of CD3⁺ CD8⁺ CD103⁺ T cells to CD3⁺ CD8⁺ T cells (n = 5 to 15/group). (B) Lymphocytes were purified from perfused whole brains of mice infected for 7 or ≥90 days and immunostained for CD103. The percentage of CD103⁺ cells of the CD3⁺ CD8⁺ population is shown. (C) Lymphocytes were purified from perfused whole brains of mice infected for ≥90 days; the percentage of CD69⁺ cells among CD3⁺ CD8⁺ CD103⁺ T cells in the brains of uninfected or persistently infected NSE-CD46⁺ mice is shown. (D) Lymphocytes purified from whole-brain tissue of mock-infected mice (PBS), mice inoculated with inactivated virus (UV MV), or mice infected with replication-competent MV, collected at 90 dpi, and subjected to flow cytometric analysis. CD103⁺ CD3⁺ CD8⁺ cells are shown as a percentage of total CD3⁺ CD8⁺ T cells (n ≥ 6/group). The percentage of CD3⁺ CD8⁺ CD103⁺ (T_rm) cells among CD3⁺ CD8⁺ T cells in brains of mice infected for ≥90 days (n = 5 to 8/group) is also shown. (E and F) Lymphocytes purified from perfused whole brains of mice infected for ≥90 days. (E) Percentages of IFN-γ⁺ CD3⁺ CD8⁺ CD103⁺ and CD3⁺ CD8⁺ CD103⁻ cells (n = 8/group). (F) Percentages of granzyme B⁺ CD3⁺ CD8⁺ CD103⁺ and CD3⁺ CD8⁺ CD103⁻ cells (n = 8/group). #, P < 0.05, Mann-Whitney U test. Data are representative of those from at least 2 independent experiments.