Apoptotic neutrophils suppress DCs and macrophages promoting what outcome?

• A. Tissue repair
• B. Parasite infection
• C. Antibody production
• D. Resolution of inflammation

Answer: (B)

Engulfment of apoptotic neutrophils by macrophages and dendritic cells sends anti-inflammatory signals that promote resolution of inflammation. This process, efferocytosis, makes macrophages adopt a tissue-repairing, anti-inflammatory state (often M2-like) and drives dendritic cells toward a tolerogenic profile. They reduce maturation and pro-inflammatory cytokine production while increasing anti-inflammatory mediators such as IL-10 and TGF-β. The overall result is dampened inflammation and commencement of tissue repair, returning the tissue to homeostasis. This environment would not favor parasite infection, since clearing parasites typically requires active inflammatory and adaptive responses; antibody production also depends on antigen presentation and helper signals that are reduced in this anti-inflammatory context. Therefore, the outcome promoted is the resolution of inflammation.