The long term goal of this project is to define adjuvants and routes of immunization, which will best enhance IgA responses of long duration on the cervicovaginal mucosa. HIV infection is most often sexually transmitted, but little is known of adjuvants or routes which enhance long lasting IgA antibody with anamnestic responses at the female genital mucosa. We will compare oral and intravaginal routes with the subcutaneous route since human systemic immunization is routine. The female genital tract is part of the common mucosal immune system, so the oral route should stimulate cervicovaginal IgA. However since homing of IgA immunocytes is partially organ specific, it is important to test the intravaginal route as well. Adjuvants to be studied include alum, because it is licensed for human use and currently used in many human vaccines; Quil A, a partially purified saponin which enhances T and B cell responses both systemically and locally; and cholera toxin which enhances IgA responses at both local and distant mucosal sites. For studies of adjuvant and route in enhancing IgA antibodies to HIV, we chose one antigen; a synthetic octameric branching peptide of the principle neutralizing determinant of HIV-1 qpl2O (octameric p2OO) because it has been shown to protect primates against SIV. Thus our specific aims are to: 1) Immunize mice with octameric p2OO and alum, Quil A or cholera toxin (CT) adjuvants by oral, intravaginal and subcutaneous routes (except CT). Isotypic antibody responses in serum and vaginal secretions will be determined by ELISA (Experiment 1). 2) Determine neutralizing antibody (NA) and ADCC titers of serum and vaginal samples. 3) Determine the duration of responses and the role of anamnestic responses in serum and secretions (Experiment 2). 4) Compare vaginal and systemic isotypic antibody titers at different stages of the sexual cycle. 5) At the end of experiments 1 and 2, compare antibody responses (ELISA for IgG subclasses and IgA, NA and ADCC) in uterine, vaginal and gut washes with serum antibody. The results of these studies should define adjuvants for long lasting cervicovaginal mucosal antibodies which have neutralizing and ADCC activity for HIV. Also the comparison of oral and vaginal routes should define whether oral immunization is optimal for this sexually transmitted infection.
