TNF and infection: However, the mice infected with a sub-lethal dose of L. interrogans strain Lai displayed much less elevated serum cytokines during the acute phase of infection, including four proinflammatory factors (IL-1β, IL-6, IL-17 and TNF-α), an anti-inflammatory factor (IL-10) and two chemotactic factors (MCP-1 and RANTES) (Figure 1A and 1C).