Immunogenicity evaluation of DNA vaccines that target guinea pig cytomegalovirus proteins glycoprotein B and UL83

Vaccines are needed for control of congenital human cytomegalovirus (HCMV) infection. Although the species-specificity of cytomegaloviruses precludes preclinical evaluation of HCMV vaccines in animal models, the guinea pig cy tomegalovirus (GPCMV), which causes disease in utero, is a relevant model f or the study of vaccines against congenital infection. We investigated whet her DNA vaccines that target two GPCMV proteins, glycoprotein B (gB) and UL 83 (pp65), are capable of eliciting immune responses in vivo. After cloning each gene into an expression vector, DNA was delivered by intramuscular in oculation and by pneumatic epidermal delivery. In Swiss-Webster mice, anti- gB titers were significantly higher after epidermal delivery. After epiderm al inoculation in guinea pigs, all gB-immunized animals (n = 6) had antibod y responses comparable to those induced by natural infection. Viral neutral ization titers ranged from 1:64 to greater than 1:128, A GPCMV UL83 DNA vac cine also elicited an antibody response in all immunized guinea pigs (n = 6 ) after epidermal administration. Immunoprecipitation and Western blot assa ys confirmed that immune sera were immunoreactive with virion-associated UL 83 and gB proteins. We conclude that DNA vaccines against GPCMV structural proteins are immunogenic, and warrant further investigation in the guinea p ig model of congenital CMV infection.