Brucella abortus RB51 lipopolysaccharide influence as an adjuvant on the therapeutic efficacy of HPV16 L1 and HPV16 E7 DNA vaccines

Objective(s): Human papillomavirus (HPV) is a primary contributing agent of cervical cancer. Eradication of HPV-related infections requires therapeutic strategies. We used Brucella abortus RB51 rough lipopolysaccharide (R-LPS) as an adjuvant along with two HPV16 therapeutic DNA vaccines, pcDNA3-E7 and pcDNA3-L1, for improving DNA vaccine efficacy. Materials and Methods: For evaluation of the B. abortus LPS adjuvant efficacy in combination with DNA vaccines to induce cellular immune responses, C57BL/6 mice were immunized with the DNA vaccines, with or without R-LPS adjuvant. IFN-γ and IL-4 cytokines assay was carried out for assessment of cellular and humoral immune responses. Results: Findings indicated that vaccination with pcDNA3-E7 or pcDNA3-L1 alone could induce strong cellular immune responses, but stronger antigen-specific T-cell immune responses were shown by co-administration of HPV16 E7 and HPV16 L1 DNA vaccines along with R-LPS adjuvant. Conclusion: Overall, B. abortus R-LPS through enhancement of T-cell immune responses can be considered an efficient vaccine adjuvant in future studies and trials.