Aggregate complexes of HIV-1 induced by multimeric antibodies

Area of Science:

• Immunology
• Virology
• Vaccine Development

Background:

• Antibody-mediated viral aggregation may prevent HIV transfer across mucosal surfaces.
• Understanding antibody characteristics for HIV aggregation is key for vaccine design.
• Immune exclusion at mucosal entry points is a critical goal for HIV prevention.

Purpose of the Study:

• To investigate the potential of different antibody isotypes (IgG and IgA) and forms (monomeric vs. dimeric) to induce HIV-1 aggregation.
• To determine how epitope specificity affects HIV-1 aggregation induced by dimeric IgA (dIgA).

Main Methods:

• Dynamic Light Scattering (DLS) was used to assess viral aggregation.
• Monoclonal antibodies (mAbs) of IgG and IgA isotypes, as well as polyclonal HIV-Ig, were tested.
• IgA purified from RV144 vaccine trial responders was analyzed for opsonization and aggregation capabilities.

Main Results:

• Neither neutralizing nor non-neutralizing IgG mAbs nor polyclonal HIV-Ig could form HIV-1 viral aggregates.
• Dimeric IgA (dIgA) mAbs, but not monomeric IgA, induced stable HIV-1 viral aggregates.
• Epitope specificity influenced the degree of aggregation and higher-order complex formation by dIgA.
• IgA from RV144 responders efficiently opsonized viral particles without significant aggregation.

Conclusions:

• Dimeric IgA (dIgA) demonstrates the capacity to form stable HIV-1 aggregates.
• Viral aggregation by dIgA offers a potential mechanism for immune protection at mucosal entry sites.
• These findings support further investigation into aggregation as a protective strategy against HIV infection.