Dendritic cell function during chronic hepatitis C virus and human immunodeficiency virus type 1 infection

Area of Science:

• Immunology
• Virology
• Cell Biology

Background:

• Chronic Hepatitis C virus (HCV) infection can persist despite T-cell immunity and is more severe in patients coinfected with human immunodeficiency virus type 1 (HIV-1).
• Dysfunctional antigen-presenting myeloid dendritic cells (DCs) may contribute to impaired T-cell responses in HCV and HIV-1 coinfection.

Purpose of the Study:

• To investigate the functional capacity of monocyte-derived DCs in patients with chronic HCV infection, with or without HIV-1 coinfection.
• To identify potential defects in DC function and explore strategies to overcome them for improved immunotherapy.

Main Methods:

• Monocyte-derived DCs were generated from individuals with chronic HCV, HCV/HIV-1 coinfection, and healthy controls.
• DCs were stimulated with CD40 ligand (CD40L), gamma interferon (IFN-gamma), tumor necrosis factor alpha, and IL-1beta.
• Interleukin-12 (IL-12) p70 production, DC surface molecule expression, and T-cell stimulatory capacity were assessed.

Main Results:

• DCs from HCV-infected individuals, with or without HIV-1 coinfection, produced lower levels of IL-12 p70 in response to CD40L.
• IL-12 production defects were overcome by co-stimulation with CD40L and IFN-gamma, and by blocking IL-10.
• DC capacity to stimulate allogeneic CD4+ T cells and induce cytokines like IL-2, IL-5, and IL-10 remained unimpaired.

Conclusions:

• Myeloid DCs from chronic HCV-infected individuals exhibit impaired IL-12 p70 production, associated with IL-10 activity.
• This IL-12 deficiency can be therapeutically reversed using CD40L and IFN-gamma, indicating preserved DC potential.
• The findings support the rationale for developing DC-based immunotherapy for chronic HCV infection.