GM-CSF released during immune response to virus cause unresponsiveness to antigen stimulation.
Three BALB/c mice were immunized intravenously with 5 × 106 PFU per mouse of either IL-2-rVV or IFN-γ-rVV recombinant viruses expressing the antigen β-gal, together with the mouse cytokines IL-2 and IFN-γ, respectively. On days 1, 3, and 5, IL-2-rVV immunized mice were inoculated intraperitoneally with 0.2 mL of PBS containing 100 μg of either an antiserum neutralizing mouse GM-CSF activity or the goat control serum. After 6 days, the spleens were removed, pooled, incubated in vitro with 1 μg/mL of the β-gal peptide for 5 days, and then assayed in a 51Cr-release assay against the CT26 cells or with CT26 cells pulsed with the β-gal peptide. E:T cell ratios are indicated; spontaneous release never exceeded 20%.
