Identification of Mycoplasma mycoides subsp. mycoides small colony genes coding for T-cell antigens

Genes of the Mycoplasma mycoides subsp. mycoides small colony biotype (MmmSC) coding for proteins capable of eliciting protective T-cell memory responses have potential for incorporation into a recombinant subunit vaccine against contagious bovine pleuropneumonia (CBPP). Here we used lymphocytes from cattle that had completely recovered from infection to screen products of MmmSC genes for recognition by CD4(+) effector memory (Tem) and central memory (Tcm) T lymphocytes. Six MmmSC genes (abc, gapN, glpO, lppA, lppB, and ptsG) were expressed as histidine-tagged recombinant polypeptides, or synthetic overlapping peptides, before inclusion in proliferation and gamma interferon (IFN-gamma) assays. Only two MmmSC antigens, LppA and PtsG, consistently induced recall proliferation from immune CD4(+) T cells and IFN-gamma production in all animals tested. Moreover, LppA and PtsG were shown to possess epitopes recognized by both short-lived CD4(+) Tem and long-lived CD4(+) Tcm cells.