Alterations of CCR2 and CX3CR1 on Three Monocyte Subsets During HIV-1/Treponema pallidum Coinfection

Area of Science:

• Immunology
• Infectious Diseases
• Cell Biology

Background:

• HIV-1 and syphilis (Treponema pallidum) coinfection presents a significant global health challenge.
• Monocyte subsets express chemokine receptors CCR2 and CX3CR1, influencing immune responses.
• Dynamic changes in these receptors during coinfection remain incompletely understood.

Purpose of the Study:

• To investigate the expression patterns of CCR2 and CX3CR1 on three distinct monocyte subsets in individuals with HIV-1 and/or T. pallidum coinfection.
• To elucidate the role of these chemokine receptors in the pathogenesis of HIV-1 and syphilis coinfection.

Main Methods:

• Utilized cell surface staining techniques to quantify CCR2 and CX3CR1 expression.
• Analyzed expression levels across different monocyte subsets in various patient groups: acute HIV-1 infected (AHI), chronic HIV-1 infected without (CHI+ ART-) and with (CHI+ART+) antiviral therapy, rapid plasma reagin-positive (RPR+), and combinations thereof (CHI+RPR+ ART-, CHI+RPR+ART+).

Main Results:

• CCR2 density decreased on classical monocytes across all studied HIV-1 and/or T. pallidum infected groups.
• CX3CR1 density increased on all three monocyte subsets during HIV-1 and/or T. pallidum infection.
• CX3CR1 levels differed between patient groups, being lower in CHI+ ART- compared to CHI+ART+ individuals, and lower in CHI+ART+ compared to CHI+RPR+ART+ individuals.

Conclusions:

• The study reveals significant alterations in CCR2 and CX3CR1 expression on monocyte subsets during HIV-1 and syphilis coinfection.
• These changes in chemokine receptor dynamics provide novel insights into the immunopathogenesis of this dual infection.
• Findings highlight the potential involvement of monocyte subset modulation via CCR2 and CX3CR1 in disease progression and treatment responses.