Microbiologia Médica e Diagnóstico

Topical Mucosal Vaccination with Angiotensin (1-7) and Feline Immunodeficiency Virus Induces Secretory IgA Responses

Abstract

Robert A. Larsen, Kathleen E. Rodgers, W. Martin Kast, Diane Da Silva, Rosa Altomstone, Christopher Meeks, Gere S. diZerga and John M. Leedom

Background: Pre-existing mucosal generated secretory IgA antibodies may prevent transmission of HIV. The present study aimed to characterize mucosal antibodies generated following topical vaccination with a novel mucosal adjuvant, angiotensin (1-7), in combination with a killed feline immunodeficiency virus (FIV) vaccine used as a model antigen.

Methods: Female outbred cats were vaccinated with Fel-O-Vax FIV vaccine agent combined with increasing concentrations of angiotensin (1-7) [A (1-7)] applied topically to oral, vaginal and rectal surfaces weekly for six weeks. Control animals received intramuscular vaccinations with the Fel-O-Vax FIV alone or with A (1-7). Mucosal secretions were evaluated for antibody responses against FIV-p24 antigen or HIV-gp120 antigen.

Results: Topical application of whole killed FIV virus with A (1-7) induced substantial secretory IgA (SIgA)-antigp120 antibodies in oral, vaginal and rectal secretions across a wide ranges of A (1-7) dose levels. Intramuscular vaccination of FIV antigen with A (1-7) induced high levels of SIgA-anti-gp120 antibodies at vaginal and rectal sites. The topical application vaccination strategy elicited only very weak systemic immune responses.

Conclusion: Angiotensin (1-7) is a potent mucosal vaccine adjuvant.