Lactoferrin-monophosphoryl lipid A complex enhances immunity of mice to Plesiomonas shigelloides CNCTC 138/92.

Our previous study showed the efficacy of lactoferrin-monophosphoryl lipid A isolated from Hafnia alvei LPS complex (LF-MPL(H.a.)) as an adjuvant in stimulation of humoral and cellular immune response in mice to conventional antigens and a lower pyrogenicity of the complex as compared with MPL(H.a.) alone. In the present investigation we demonstrated that LF-MPL(H.a.) complex enhanced the immunity of BALB/c mice immunized with Plesiomonas shigelloides CNCTC 138/92 bacterial vaccine, against P. shigelloides infection. The adjuvant effect was evidenced by a significant increase of the antigen-specific serum IgG, IgG(2a), and IgG(1) and elevation of antigen-specific serum IgA concentrations. In addition, application of the adjuvant facilitated better clearance of the bacteria in spleens and livers of infected mice when compared with MPL(H.a.) alone. These features of the new adjuvant may predispose it for vaccination protocols in humans.