FIG 8.

Effect of C. muridarum gastrointestinal colonization on intestinal immune responses to nonchlamydial infection. C57BL/6J female mice without (top; Control) or with (bottom, C. muridarum) CM-mCherry colonization in the GI tracts for 22 days were intravenously injected with 10,000 naive CD8⁺ T cells purified from P14 mice (Donor P14) and immediately infected intraperitoneally with 2 × 10⁵ PFU of LCMV. Seventeen days after LCMV infection, the mice were sacrificed and splenocytes and intestinal intraepithelial lymphocytes (IEL) were isolated. Splenocytes were used for monitoring the donor P14 mouse and endogenous CD8⁺ T cell populations (A), while the small intestine (SI) IELs were used for measuring LCMV epitope-specific gut-resident memory cells using flow cytometry (B). Representative fluorescence-activated cell sorting profiles are shown. Three mice from each group were analyzed, and similar results were observed for each mouse. LCMV infection induced similar numbers of P14 IELs positive for both CD103 and CD69 (gut-resident memory CD8⁺ T cells) in mice with or without C. muridarum colonization.