Development of two avidity-based assays to detect recent HIV type 1 seroconversion using a multisubtype gp41...

Area of Science:

• Virology
• Immunology
• Epidemiology

Background:

• Current laboratory methods for detecting recent HIV-1 infections have limitations in performance across different subtypes and populations.
• Accurate estimation of HIV incidence requires sensitive and specific methods for identifying recent infections.

Purpose of the Study:

• To develop and evaluate novel assays for detecting recent HIV-1 infections using a newly engineered recombinant protein, rIDR-M.
• To assess the performance of rIDR-M in distinguishing recent from long-term HIV-1 infections across various subtypes.

Main Methods:

• Development of a recombinant protein (rIDR-M) targeting conserved regions of HIV-1 gp41 from major subtypes.
• Utilization of rIDR-M in two assay formats: a two-well avidity index assay (AI-EIA) and a one-well limiting antigen avidity assay (LAg-avidity EIA).
• Inclusion of a pH 3.0 dissociation buffer to enhance detection of low-avidity antibodies indicative of recent infection.

Main Results:

• The rIDR-M protein demonstrated reactivity with HIV antibodies across diverse subtypes.
• Both AI-EIA and LAg-avidity EIA formats efficiently distinguished recent from long-term HIV-1 infections in a seroincidence panel.
• The one-well LAg-avidity EIA with dissociation buffer showed the most efficient detection of recent infections.

Conclusions:

• Avidity-based assays employing the rIDR-M antigen offer improved accuracy for detecting recent HIV-1 infections.
• These novel assays have the potential to enhance the estimation of HIV incidence in populations with diverse HIV-1 subtypes.
• The developed methods address limitations of current incidence assays, paving the way for better HIV surveillance.