Neutrophils aid in protection of the vaginal mucosae of immune mice against challenge with herpes simplex virus type 2

Large numbers of polymorphonuclear leukocytes (PMNs) infiltrated the murine vaginal mucosa within 24 h after intravaginal inoculation with an attenuat ed strain of herpes simplex virus type 2 (HSV-2). The role of these cells i n resolution of a primary genital infection and in protection of HSV-immune animals against challenge with a fully virulent HSV-2 strain was investiga ted. Depletion of greater than 95% of the PMNs at the vaginal mucosal surfa ce Drier to intravaginal inoculation with an attenuated HSV-2 strain result ed in significantly higher virus titers on days 3 to 7 but only slightly de layed resolution of the primary genital infection. These results suggest th at neutrophils helped control the infection but that other immune mechanism s ultimately cleared the virus, interestingly, depletion of PMNs from HSV-i mmune mice prior to challenge with a fully virulent HSV-2 strain resulted i n a rise in virus titers to levels comparable to those of nonimmune mice an d a more pronounced diminution of virus clearance from the vaginal mucosa d espite the presence of HSV-specific B and T cells. Levels of gamma interfer on (IFN-gamma) and HSV-specific antibody were comparable in neutrophil-depl eted and control-treated immune mice following HSV-2 challenge, suggesting that RB6-8C5 treatment did not impair T- and B-cell function. Therefore, th ese results suggest that neutrophils play a role in limiting and clearing H SV-2 vaginal infections and that they are, in association with HSV-specific B and T cells, an important component in immune protection of the vaginal mucosa.