FIGURE 4. Antigen-independent, CD44-dependent mechanism of visceral immunosurveillance.

(A) Congenically marked effector P14 (4×10⁶) and OT-I (7×10⁶) CD8 T cells from day 6 post infection with LCMV and VSV-OVA immune chimeras, respectively, were co-injected i.p. into LCMV infection-matched recipients. 3h after i.p. injection, adhered P14 and OT-I were quantified by immunofluorescence. n=4, representative of n=9 from 2 independent experiments. (B) Effector P14 cells from day 6 LCMV immune chimeras were untreated (Ctrl) or treated with pertussis toxin (PTx) in vitro then injected (4-12×10⁶ cells) i.p. into day 6 LCMV infection-matched hosts. 3h later, adhered P14 cells were quantified by immunofluorescence. n=6 from 2 independent experiments. Graphs show mean and SEM. Mann-Whitney statistical analysis, **p 0.0043, *p 0.0260. (C) 6 days after LCMV infection, lymphocytes from WT or CD44KO mice were injected i.p. into WT infection matched recipients. 3h after i.p. injection, adhered CD8β+ transferred cells were quantified by immunofluorescence. n=8 representative of 2 separate experiments. Graphs show mean and SEM. Wilcoxon statistical analysis, **p 0.0043. (D) 4-9×10⁶ day 6 effector P14 were untreated or treated with anti-CD44 antibody in vitro for 1h prior to i.p. injection into untreated or hyaluronidase treated LCMV infection-matched recipients, respectively. 3h later, adhered P14 were quantified by immunofluorescence. n=6 from 2 separate experiments. Graphs show mean and SEM. Mann-Whitney statistical analysis, **p 0.0027, *p 0.0116.