A novel vaccine vector: herpes simplex virus type-2 deleted in glycoprotein D (HSV-2 ΔgD) and expressing modified influenza A (IAV) hemagglutinin (HA) antigens

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) cause significant global morbidity and mortality. In collaboration, the Jacobs and Herold laboratories generated an attenuated herpes simplex virus type 2 (HSV-2) strain deleted in glycoprotein D (HSV-2 Δ gD ) and demonstrated that it triggers an FcγRIV activating response that elicits both antibody-dependent cell-mediated cytotoxicity and phagocytosis. The antibodies rapidly clear virus and prevent the establishment of latency in mice and guinea pigs following challenge with several clinical isolates of both HSV-1 and HSV-2. We therefore propose that HSV-2 ΔgD is an ideal vaccine vector to induce immunity against a wide array of pathogens. The HSV genome is difficult to work with due to high GC content, repetitive regions, and tendency toward attenuation. Using Gibson cloning and homologous recombination we introduce exogenous genes such as red fluorescent protein (rfp) and influenza A (IAV) hemagglutinin (HA) into the HSV genome. IAV HA is a great model antigen to study the immunogenicity of proteins inserted into the HSV-2 Δ gD backbone. Moreover, cloning both full-length and stalk HAs into the HSV-2 Δ gD genome will test the influence of immunodominant antigens on the character of our antibody response. Our expression vectors, verified by digestion and sequencing, encode a chimeric gD/HA protein that contains the signal sequence and cytosolic and transmembrane domains of HSV-2 gD . These modifications will promote trafficking of HA to the cell membrane and viral envelope. Our recombination system has produced an RFP + HSV-2 ΔgD virus that we verified by fluorescence, digestion and sequencing. The kinetics of infection with the RFP + virus match that its parental HSV-2 Δ gD strain.