CD4 and typhoid fever: FliC is a bacterial flagellin known to induce an innate response through its activity on TLR5 or NLRC4, and its use as a diagnostic marker of acute typhoid fever has been suggested.21 When administered as a vaccine antigen in mice, FliC enhanced subsequent induction of IFN-γ CD4 responses and bacterial clearance in mice subsequently infected with S. Typhimurium.22 A number of fimbrial subunits and fimbria-associated proteins also induced an IFN-γ response, including StaB, SteEF, StcA, and FimF.