Ovalbumin-pulsed neutrophils induce naive CD8⁺ T-cell differentiation into effector cells. (A) OT1 CD8⁺ T cells were adoptively transferred into β2-microglobulin^−/− mice. One day later, the mice were injected intravenously with PBS, Ova, Ova-pulsed LB27.4, Ova-pulsed BMNs, or Ova-pulsed DCs. Three days later, spleen CD8⁺ T cells were purified and IL-2 and IFN-γ production was analyzed by ELISA, or mice were injected intravenously with target cells prepared as described in “In vivo cytolysis assay.” After 3 hours, cytolysis was analyzed by FACS. (B) At day 5, IFN-γ and IL-2 production was determined by ELISA 24 hours after in vitro restimulation. Results are expressed in ng/mL (IFN-γ) and in pg/mL (IL-2) as mean (± SD) of 3 separate experiments. Mann-Whitney test was performed. The data were statistically significant for DCs and PMNs (*P < 0.03) when compared with controls. (C) In vivo cytolysis assay was performed by injecting 3 × 10⁶ unpulsed CFDA-SE^low–labeled splenocytes and 3 × 10⁶ SIINFEKL-pulsed CFDA-SE^high–labeled splenocytes. Three hours later, CDFA-SE expression was analyzed by FACS in spleen and lymph nodes. Percentage of lysis was calculated as described in “In vivo cytolysis assay.” Results are expressed as mean (± SD) of 3 separate experiments. ANOVA test was performed. The data were statistically significant for DCs and PMNs (*P < .001) when compared with controls.