Isotype profiles of anti-gp160 antibodies from HIV-infected patients in plasma and culture supernatants

Identifying Recent HIV Infections: From Serological Assays to Genomics

In this paper, we review serological and molecular based methods to identify HIV infection recency. The accurate identification of recent HIV infection continues to be an important research area and has implications for HIV prevention and treatment interventions. Longitudinal cohorts that follow HIV negative individuals over time are the current gold standard approach, but they are logistically challenging, time consuming and an expensive enterprise. Methods that utilize cross-sectional testing and biomarker information have become an affordable alternative to the longitudinal approach. These methods use well-characterized biological makers to differentiate between recent and established HIV infections. However, recent results have identified a number of limitations in serological based assays that are sensitive to the variability in immune responses modulated by HIV subtypes, viral load and antiretroviral therapy. Molecular methods that explore the dynamics between the timing of infection and viral evolution are now emerging as a promising approach. The combination of serological and molecular methods may provide a good solution to identify recent HIV infection in cross-sectional data. As part of this review, we present the advantages and limitations of serological and molecular based methods and their potential complementary role for the identification of HIV infection recency.

HIV-1-specific antibody responses during acute and chronic HIV-1 infection

PURPOSE OF REVIEW

The humoral immune response to HIV-1 throughout infection is comprised of complex mixtures of antibody isotypes with numerous HIV-1 specificities. However, unlike antibody responses to most infections, protective antibody responses are delayed and do not arise until long after HIV-1 latency is established. We review recent data on HIV-1-specific antibody isotypes induced following HIV-1 transmission: to understand the effects of HIV-1 on B cell and T cell effector responses, to understand the timing of the rise and fall of different anti-HIV-1 antibodies and to understand how antibodies could contribute to protective immunity if they were either pre-existing or elicited immediately after HIV-1 transmission.

RECENT FINDINGS

Studies of the earliest events following infection by the transmitted/founder virus have recently revealed that early destruction of B cell generative microenvironments may be responsible for delay of potentially protective anti-HIV-1 antibody responses. Unlike the initial CD8 T cell response to HIV-1, the initial induced antibody response is usually ineffective in controlling virus replication during acute HIV-1 infection.

SUMMARY

The antibody isotypes and specificities elicited during HIV-1 infection can provide a window into deciphering the detrimental effects of HIV-1 on B cell and T cell responses. Additionally, further characterization of the virus inhibitory capabilities of anti-HIV-1 antibody isotypes can define the spectrum of potential protective HIV-1 antibodies that could be readily elicited by experimental vaccines and adjuvants.