Circulating CD14brightCD16+ 'intermediate' monocytes exhibit enhanced parasite pattern recognition in human helminth...

Area of Science:

• Immunology
• Parasitology
• Cell Biology

Background:

• Monocyte subsets modulate immune responses in infectious diseases.
• Their role in helminth infections, like schistosomiasis, remains largely unexplored.
• Schistosoma mansoni and S. haematobium co-infection is prevalent in endemic areas.

Purpose of the Study:

• To investigate the abundance and antigen-binding capacity of monocyte subsets in individuals with S. mansoni and S. haematobium infections.
• To determine if monocyte subset function differs between mono-infected, co-infected, and uninfected individuals.
• To assess monocyte recognition of schistosome excretory/secretory (E/S) products.

Main Methods:

• Peripheral blood mononuclear cells (PBMCs) were isolated from participants in Northern Senegal.
• Monocyte subsets (classical, intermediate, non-classical) were identified using flow cytometry.
• Binding of schistosome E/S products (cercarial and egg) to monocyte subsets was quantified.

Main Results:

• All three monocyte subsets bound schistosome E/S products.
• 'Intermediate' (CD14brightCD16+) monocytes exhibited significantly enhanced binding to both cercarial and egg E/S products.
• This enhanced binding in intermediate monocytes was most pronounced in individuals co-infected with both S. mansoni and S. haematobium.

Conclusions:

• This study demonstrates, for the first time, that intermediate CD14brightCD16+ monocytes show altered parasite antigen recognition during helminth infection.
• The enhanced ligand binding by intermediate monocytes, particularly in co-infected individuals, may influence immune responses to schistosomiasis.
• These findings highlight a potential functional role for intermediate monocytes in the immunopathology and immunity of helminth infections.