In acute inflammation, which cells are primarily responsible for phagocytosis of bacteria?

• A. Platelets
• B. Neutrophils and monocytes
• C. Lymphocytes
• D. Erythrocytes

Answer: (B)

In acute inflammation, the main work of clearing bacteria is done by professional phagocytes: neutrophils and monocytes (which become macrophages once in tissue). Neutrophils are the rapid first responders that rush to the site, grab bacteria, and digest them inside phagolysosomes using reactive oxygen species and lysosomal enzymes. Monocytes migrate into the tissue and differentiate into macrophages, providing longer-term phagocytosis and also helping clear debris and orchestrate the inflammatory response through cytokine signaling.

Other cells aren’t primary phagocytes. Platelets mainly support clotting and can modulate inflammation, but they don’t perform engulfment of bacteria. Lymphocytes drive adaptive immune responses rather than immediate bacterial clearance in acute inflammation. Erythrocytes don’t engage in phagocytosis at all.

So, the combination of neutrophils and monocytes/macrophages best explains the cell types responsible for phagocytosis of bacteria in acute inflammation.