FLICKR, NIAIDResearchers have traditionally designed vaccines against herpes simplex virus type 2 (HSV-2) to elicit antibodies that targeted the viral surface protein called glycoprotein D (gD-2), which the virus uses to enter host cells. But by deleting gD-2 from the viral genome, William Jacobs of the Albert Einstein College of Medicine and his colleagues not only rendered the virus unable to infect cells, they were able to develop a vaccine that forced the murine immune system to produce antibodies that recognize different viral targets.

“We had a hunch that gD-2 might be masking other viral antigens, and that by removing this dominant protein we would expose those previously masked antigens to the immune system,” Jacobs said in a statement.

Using the gD-2–lacking virus to immunize mice, the researchers elicited complete protection against wild-type HSV-2, both when the animals were challenged intravaginally or...