A study conducted by Dr. Lu’s group at the University of Massachusetts Medical School (UMMS), recently published in Emerging Microbes & Infections (EMI), found that the PDPHV vaccine delivered as a DNA prime – Protein boost regimen elicited high levels of gp120-specific antibody secreting cells (ASC) and memory B cell responses.
Worcester HIV Vaccine (WHV) licensed the PDPHV product from UMMS three years ago to quickly advance this vaccine candidate through their product development program geared towards finding a safe and effective globally relevant HIV vaccine. This particular study, using the mouse model, evaluated different vaccination regimens of the polyvalent vaccine formulation consisting of a plasmid DNA component encoding for the HIV-1 envelop glycoprotein gp120 antigen and a recombinant gp120 protein matching the same gp120 DNA vaccine plasmid. The naked DNA vaccine was delivered by intramuscular injection in buffered saline. The gp120 protein vaccine was delivered in two different ways, with and without the adjuvant Alum. The study demonstrated that the immunization approach of DNA prime- protein boost was more effective in eliciting gp120-specific B cell response than using either the DNA or the protein vaccine alone. The data further show that by priming the immune system with the DNA vaccine, the need of including an adjuvant as part of the recombinant protein vaccine boost formulation is not as critical since the antigen-specific B cells are already activated by the DNA prime. Previously, Dr. Lu’s group also reported that gp120 DNA immunization was able to improve the T follicular helper (Tfh) cell responses and germinal center B cell development in mice but that study did not determine if the B cells were antigen-specific (read more here).
Although the DNA prime-protein boost vaccination approach has been widely used in preclinical and clinical studies especially in the field of HIV vaccine development, the exact role of DNA prime immunization has not been fully elucidated yet. Developing an effective HIV vaccine remains to be a major scientific challenge and these findings reported by Dr. Lu’s group that DNA priming plays a key role in stimulating antigen-specific B cell responses can have a major impact on the development of vaccines capable of inducing high quality and long-lasting antibody responses.
Below is the link of the recently published paper:
