Both systemic and mucosal antigen specific IgG1 and IgA antibodies were enhanced by intranasal co-delivery of poly-L-lactide microencapsulated V antigen of Yersinia pestis and IFN-γ, however this formulation was detrimental to prevent infections by systemic bacterial challenge in the murine model (Griffin et al., 2002). Here, IFNG is linked to infection.