The immune effects of multiple antigen peptides containing the mimic epitopes of the adhesion protein of Mycoplasma genitalium.

The purpose of this study was to investigate the humoral and cellular immune responses stimulated by multiple antigen peptides (MAPs) containing the mimic epitopes of Mycoplasma genitalium adhesion protein (MgPa). Three MAPs containing the mimic epitopes of MgPa were synthesized on a branched polylysine matrix. After purification and characterization, these MAPs were used to immunize BALB/c mice. The immunoglobulin G (IgG) antibody and the subtype of IgG antibody in the serum of the immunized mice were detected by indirect ELISA (enzyme-linked immunosorbent assay). The proliferation of the spleen lymphocyte was detected using the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. The gamma interferon (IFN-γ) and interleukin-4 (IL-4) levels in the cultured supernatant of spleen lymphocytes were measured by ELISA. The 3 different MAPs were prepared with high purity. Levels of IgG, IgG1, and IgG2a antibodies were elevated in the mice serum immunized by all 3 MAPs. The major antibody isotype was IgG2a. Importantly, mice immunized with a mixture of the 3 MAPs produced significantly more antibodies than those immunized with a single MAP (p < 0.05). Moreover, these MAPs could stimulate the proliferation of spleen lymphocytes of immunized mice and induce the production of IFN-γ and IL-4. The IFN-γ and IL-4 levels stimulated by the mixed MAPs were significantly higher than those stimulated by a single MAP (p < 0.01). The 3 different MAPs could induce strong cellular and humoral immune responses. The immunoreactivity of the mixed MAPs was stronger than that of the single MAP.