A new method of immunization against infectious diseases – using antigens mixed with a water-in-oil-based adjuvant– has been shown to elicit a strong immune response against smallpox and HIV in two new studies.
Nanoemulsion adjuvant is composed of soybean oil, alcohol, water and detergents emulsified into nano-scale droplets smaller than 400 nanometers in diameter. To elicit immune responses, the nanoemulsion-based vaccines are formulated by mixing the nanoemulsion with a whole disease-causing microbe or with isolated or recombinant antigens from the pathogen. It administered in form of a nasal spray to the nasal mucosa, so there is no need for injections.
Increasing epidemiological and experimental evidence underscore the importance of both virus neutralizing antibodies and robust cellular responses for controlling HIV-1 infection. In a recent study, we have documented the development of systemic and mucosal immune responses to the HIV gp120 monomer immunogen, administered intranasally in the oil-in-water nanoemulsion adjuvant. Mice and guinea pigs intranasally immunized by the application of recombinant HIV gp120 antigen mixed in nanoemulsion. The vaccinations produced robust serum anti-gp120 IgG and IgA antibody responses, and significant bronchial and distant mucosal site vaginal anti-gp120 IgA. Anti-gp120 antibodies have cross-reactive activity with various heterologous serotypes of gp120 protein. Of particular importance is that sera from immunized animals have significant neutralization activity against two class-B laboratory strains of HIV (HIVBaL and HIVSF162) and five primary clinical HIV-1 isolates. The analysis of gp120-specific CTL proliferation and INF-γ induction indicated that nasal vaccination in nanoemulsion also induced systemic, Th1-polarized cellular immune responses. This study suggests that nanoemulsion should be evaluated as a mucosal adjuvant for the future multivalent HIV vaccines. Read more in:
Anna U. Bielinska, Katarzyna W. Janczak, Jeffrey J. Landers, David M. Markovitz, David C. Montefiori, James R. Baker. Nasal Immunization with a Recombinant HIV gp120 and Nanoemulsion Adjuvant Produces Th1 Polarized Responses and Neutralizing Antibodies to Primary HIV Type 1 Isolates. AIDS Research and Human Retroviruses. February 1, 2008, 24(2): 271-281. doi:10.1089/aid.2007.0148.