Interference between human herpesvirus 7 and HIV-1 in mononuclear phagocytes

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• Human herpesvirus 7 (HHV-7) utilizes CD4 as a cellular receptor, impacting human immunodeficiency virus type 1 (HIV-1) infection of CD4+ T cells.
• Macrophages are crucial targets for HIV-1 infection in vivo.

Purpose of the Study:

• To investigate the interaction between HHV-7 and a macrophage-tropic HIV-1 isolate (HIV-1BaL) in human peripheral blood monocyte-derived macrophages.
• To determine if HHV-7 can inhibit HIV-1 replication in macrophages.

Main Methods:

• Macrophages were exposed to live or UV-inactivated HHV-7 before infection with HIV-1BaL.
• HIV-1 replication was assessed by measuring HIV-1 p24 antigen levels and proviral DNA synthesis.
• The effect of HHV-7 on cell proliferation was evaluated by mitogen stimulation of peripheral blood mononuclear cells (PBMCs).

Main Results:

• Pre-exposure to HHV-7 resulted in a significant dose-dependent inhibition of HIV-1 replication in macrophages (91.7-91.8% reduction in p24 antigen at day 7).
• HHV-7 completely inhibited the synthesis of HIV-1 proviral DNA in the early stages of infection.
• HHV-7 did not inhibit pre-established HIV-1 infections and only marginally affected PBMC proliferation.

Conclusions:

• HHV-7 acts as a potent inhibitor of HIV-1 infection in macrophages, a key cell type for HIV-1 persistence.
• The inhibitory mechanism appears to involve blocking HIV-1 entry, potentially at the CD4 receptor level.
• HHV-7 demonstrates potential as a tool for understanding and potentially combating HIV-1 infection in mononuclear phagocytes.