Molecular cloning and immune response analysis of putative variable lipoproteins from Mycoplasma mycoides subsp capri.

Mycoplasma mycoides subsp capri is the cause of goat "MAKePS" (Mastitis, Arthritis, Keratoconjunctivitis, Pneumonia, Septicemia) syndrome. We identified three genes (GL_ 000459; 000461; 000462) as variable lipoprotein genes in the M. mycoides subsp capri str. PG3 genome by genomic information and comparative genomic analyses. To study the role of variable lipoproteins in M. mycoides subsp capri pathogenesis and evaluate the immunogenic and protective potentials of those proteins, we constructed the expression systems and expressed the mature peptide portion of the three proteins in E. coli. We also determined the titers and opsonophagocytosis activity of total IgG antibodies and the levels of Th1 and Th2 cytokines in sera, and we ran a lymphocyte proliferation assay in mice immunized with recombinant proteins His-tag-GL000459, His-tag-GL000461, and His-tag-GL000462. These three lipoproteins induced humoral and cellular immune responses in the immunized mice. Additionally, the whole blood opsonophagocitic in vitro assay demonstrated that the antibodies produced by the immunized groups can neutralize strain PG3; consequently, these three variable lipoproteins could be the major surface antigens in M. mycoides subsp capri str. PG3.