Comparison of IFN-α responses of 440c⁺, 440c^-, CD11c⁺/Gr-1⁺/CD11b^-, and CD11c⁺/Gr-1^-/CD11b^+/- splenocytes to in vitro stimulation with CpG and MCMV. 440c⁺, 440c^-, Gr-1⁺/CD11b^-, and Gr-1^-/CD11b^+/- were sorted from CD11c⁺-enriched splenocytes and stimulated in vitro with MCMV or CpG ODN 2216 for 24 hours. IFN-α was measured in culture supernatants by ELISA.