Mucosal Humoral Immune Response to SIVmac239∆nef Vaccination and Vaginal Challenge

Area of Science:

• Immunology
• Vaccinology
• Reproductive Health

Background:

• Live attenuated vaccines, like nef-deleted SIV, offer strong protection against wild-type SIV in macaques.
• Identifying protection correlates is key for an effective HIV-1 vaccine.
• A pre-challenge correlate involves IgG antibodies to gp41, produced by submucosal plasma cells in ectopic follicles and concentrated by neonatal FcR.

Purpose of the Study:

• To investigate mucosal antibody production following vaginal challenge.
• To understand the role of the female reproductive tract's epithelial-immune system in vaccine response.

Main Methods:

• Analysis of plasma cell increases in the female reproductive tract and other mucosal sites post-vaginal challenge.
• Characterization of vaginal ectopic follicles.
• Assessment of antibody production, affinity maturation, and class switch recombination.

Main Results:

• Vaginal challenge rapidly increases plasma cells in the female reproductive tract and other mucosal sites.
• These increases correlate with low-level, persistent mucosal viral replication.
• Vaginal ectopic follicles exhibit organization similar to secondary lymphoid organs.

Conclusions:

• Vaccination engages the female reproductive tract's epithelial-immune axis to combat mucosal pathogens.
• Mimicking this system could significantly advance HIV-1 vaccine development.