Interferon-γ associated cytokines and chemokines produced by spleen cells from Brucella-immune mice

It is known that interferon (IFN)-γ plays a critical role in protection against brucellosis. In this study we have investigated several cytokines and chemokines that are associated with IFN-γ for potential in vitro correlates of protection. We cultured spleen cells in vitro from mice immunized orally with a live, attenuated Brucella melitensis vaccine candidate (WR201) and stimulated these cells with a lysate of B. melitensis. Differential gene expression of several cytokines and chemokines in stimulated spleen cells was analysed by real-time PCR, and secreted proteins were determined by ELISA. Immunized mice produced higher levels of both protein and gene transcripts for IFN-γ, interleukin (IL)-2, IL-18 and MIP1-α. Immunized mice also had elevated gene expression levels for IL12-p40, IL23-p19, IP-10, MIG and MCP-1 when compared to normal mice. In this study we have identified new cytokines and chemokines as potential immune correlates in responses to protection in Brucella-vaccinated mice.