An orally available Lactobacillis casei (L. casei)-based vaccine expressing the human papillomavirus (HPV) type 16 isoform E7 protein linked to the poly-gamma-glutamate synthetase complex gene PgsA, with potential immunostimulating activity. Upon oral administration, the expressed HPV 16 E7 may stimulate the immune system to mount a mucosal cytotoxic T-lymphocyte (CTL) response against HPV 16 E7-expressing tumor cells. The poly-glutamic acid synthetase PgsA from Bacillus subtilis acts as an anchoring motif that facilitates the expression of the HPV antigen protein on the surface of the bacteria. HPV 16 E7, a cell surface glycoprotein and tumor associated antigen, is overexpressed in various viral-related cancers.