Figure 6. T cell-mediated immunity alone is insufficient for protection against POWV-LB.

(A and B) Mortality (A) and weight loss (B) for mice receiving adoptively transferred T cells (both CD4⁺ and CD8⁺) from POWV-Spooner (red, POWV-Spo, n = 8) experienced, alphavirus-negative control (RVFV vaccine strain MP-12) experienced T cells (blue, MP12, n = 2) or naive T cells (black, n = 8) into naive B6 mice. B6 mice were challenged s.c. with 10² FFU POWV-Spo or saline and harvested in memory phase 30 dpi. CD4⁺ and CD8⁺ T cells were enriched via negative selection and 1×3 10⁶ cells were administered i.v. to B6 mice. Within 24 h, recipient mice were challenged s.c. with 10² FFU POWV-LB and monitored for 21 dpi. No significant differences in mortality were observed between naive and POWV-Spo recipient mice (p = 0.3592, Mantel-Cox test).

(C and D) Mortality (C) and weight loss (D) for B6 mice s.c. challenged with 10² FFU POWV-LB in control (black, n = 3) or CD4⁺ T cell-deplete (green, n = 3) conditions and monitored for 14 dpi. No significant difference in mortality (p = 0.6877) as determined by Mantel-Cox test.

(E and F) Mortality (E) and weight loss (F) for B6 mice s.c. challenged with 10² FFU POWV-LB in control (black, n = 6) or CD8⁺ T cell deplete (red, n = 7) conditions and monitored for 14 dpi (p = 0.0003, Mantel-Cox test). All data are reported as mean ± SEM.