Purpose of review
In this review, the roles of Fc-gamma receptor polymorphisms are discussed in regards to HIV-1 vaccine efficacy, HIV acquisition, and disease progression. In addition, the significance of the neonatal immunoglobulin G (IgG) Fc receptor and potential effects of the aggregated immunoglobulin A Fc receptor (FcalphaR) are addressed.
Fc receptors undoubtedly play an important role in antibody-mediated action in HIV infection and vaccines. Several studies have determined an association between polymorphic variants of Fc-gamma-RIIA and Fc-gamma-RIIIA in the acquisition and progression of HIV-1 infection, and in responses to vaccination regimens. A rather complex relationship exists between the relative affinity of these molecules and their impact on HIV disease acquisition and progression and HIV vaccine efficacy.
The discrepancies between different investigations of the role of Fc receptor polymorphisms appear to derive from the complex nature of the Fc receptor functions, including factors such as epistatic interactions and the race, sex, age, and relative risk behavior of the investigated individuals. Furthermore, Fc receptors in nonhuman primates (NHPs), the key model to study an AIDS-like disease in an animal model, appear to be even more diverse than in humans, and the function of these proteins has not been extensively explored. Given the critical role of Fc receptors in antibody-mediated function in humans and NHP, more investigations are needed to fully understand and exploit these functions for vaccine design.