Pro-inflammatory cytokines IL-1β and TNF-α are increased in serum from MCP-1-/- mice after LPS treatment. MCP-1+/+ or MCP-1-/- mice were injected i.p. with LPS or saline, and serum was collected 6 hours later. IL-1β (A) and TNF-α (B) levels were measured by ELISA as described in Methods. Values are represented as mean ± SEM of duplicate determinations and are pooled from two independent experiments, n = 5–11 mice per group. LPS-injected MCP-1+/+ mice mean value is 577.6 pg/ml (IL-1β) and 573.4 pg/ml (TNF-α). ** represents significant difference between LPS-treated MCP-1+/+ mice and LPS-treated MCP-1-/- mice, p < 0.001; # represents significant difference between saline-treated MCP-1+/+ mice and LPS-treated MCP-1+/+ mice, p < 0.05; and ≠ represents significant difference between saline-treated MCP-1-/- mice and LPS-treated MCP-1-/- mice, p < 0.001.