HIV-1 gp120 mannoses induce immunosuppressive responses from dendritic cells

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• The HIV-1 envelope glycoprotein gp120 is a key vaccine candidate.
• Gp120 interacts with various cell surface receptors, influencing immune signaling.
• Understanding these interactions is crucial for effective vaccine development.

Purpose of the Study:

• To investigate how receptor interactions affect immune responses to HIV-1 gp120.
• To determine the role of mannose C-type lectin receptors (MCLR) in gp120-induced immune modulation.
• To explore strategies for enhancing the immunogenicity of gp120-based vaccines.

Main Methods:

• Studied the interaction of HIV-1 gp120 strains (JR-FL, LAI, KNH1144) with human monocyte-derived dendritic cells (MDDCs) in vitro.
• Assessed IL-10 expression, receptor usage (MCLR, CD4, CCR5, CXCR4), and signaling pathways (ERK).
• Investigated the impact of mannose modification, blocking antibodies, and receptor inhibitors on cellular responses.

Main Results:

• HIV-1 gp120 (strains JR-FL, LAI) induced IL-10 in MDDCs via MCLR, notably DC-SIGN.
• Mannose-binding agents and MCLR-specific antibodies inhibited IL-10 induction.
• Gp120-treated MDDCs showed impaired maturation and reduced T cell proliferation, dependent on MCLR but independent of IL-10.

Conclusions:

• MCLR-mediated signaling by gp120 suppresses dendritic cell function and adaptive immune responses.
• Enzymatic removal of mannose residues or using blocking agents may improve vaccine immunogenicity.
• Targeting MCLR interactions could be a strategy to enhance the efficacy of HIV-1 Env-based vaccines.