Human complement component factor B rescues HIV-1-infected leukemic T cells from cytopathic death

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• Human immunodeficiency virus type 1 (HIV-1) infection leads to cytopathic cell death in CD4+ T-cells.
• Standard cell culture conditions using fetal calf serum (FCS) do not prevent HIV-1-induced cell death.

Purpose of the Study:

• To investigate the protective effect of normal human serum (NHS) on HIV-1-infected T-cell lines.
• To identify the components within NHS responsible for this protective effect.
• To assess the impact of NHS on viral load and cell resistance to HIV-1.

Main Methods:

• Culturing HIV-1-infected CD4+ T-cell lines (CEM and MT4) with varying concentrations of NHS.
• Comparing cell survival and growth in cultures with NHS versus FCS.
• Analyzing surface CD4 expression and viral genome reduction in surviving cells.
• Investigating the role of complement factor B and its co-factors.

Main Results:

• Addition of 5-10% NHS rescued HIV-1-infected T-cells from cytopathic death, allowing cell growth within 10 days.
• Cells cultured with FCS showed complete cell death within 10 days.
• Surviving cells exhibited reduced surface CD4 expression and became resistant to HIV-1 re-infection.
• Viral genomes were significantly reduced in surviving cells, with complete clearance in one cell line (CEM) within 30 days.
• The protective effect was attributed to complement factor B and associated co-factors.

Conclusions:

• Normal human serum, specifically factor B, demonstrates a protective effect against HIV-1-induced cytopathic effects in T-cells.
• Factor B may play a significant role in conferring resistance to HIV-1 infection.
• These findings suggest potential therapeutic applications for factor B in managing HIV-1 infection.