Effect of CCR8 deletion on secondary type 1 (PPD) and type 2 (SEA) granuloma formation. Groups of CCR8+/+ (129 × B6) and CCR8−/− (129 × B6) mice were sensitized subcutaneously with M. bovis PPD in Freund's adjuvant or intraperitoneally with 3,000 S. mansoni eggs. After 14 d of sensitization, lung granulomas were elicited with 6,000 PPD or SEA Ag-coated beads. Granulomas were examined on day 4 after bead challenge. (Top left) Type 1 and type 2 granuloma cross-sectional areas. (Top right) Cellular composition of type 1 and type 2 lung granulomas. Five to six mice per group. (Bottom) Histologic appearances of type 2 (SEA) bead granulomas in CCR8+/+ and CCR8−/− (original magnifications: ×400; inset, ×800). All observations were repeated in three separate experiments. Bars are means ± SEM. *P < 0.05 comparing CCR8+/+ to CCR8−/−. Findings were similar in separate studies using either 129sv or 129sv × C57BL/6 F2 background mice. Lym, lymphocytes; Mac, macrophages; Eos, eosinophils; Neu, neutrophils.
{}