Neutrophils are a type of white blood cells that are involved in the innate immune response. They are the first cells to be recruited to the site of infection or injury and play a crucial role in engulfing and destroying pathogens.

Mechanism of engulfing pathogens by neutrophils:

1. Chemotaxis: Neutrophils are attracted to the site of infection or injury by chemical signals released by damaged cells or invading pathogens.

2. Adhesion: Neutrophils adhere to the endothelial cells lining the blood vessels at the site of infection or injury, allowing them to exit the bloodstream and enter the tissues.

3. Phagocytosis: Once in the tissues, neutrophils use their cytoplasmic extensions called pseudopodia to engulf pathogens such as bacteria, fungi, and viruses.

4. Degranulation: Neutrophils release granules containing enzymes and antimicrobial peptides that can kill or inhibit the growth of pathogens.

5. Apoptosis: Neutrophils have a short lifespan and undergo apoptosis (programmed cell death) after engulfing pathogens. The dead neutrophils are then removed by other immune cells, preventing further tissue damage.

In summary, neutrophils are highly specialized cells that can rapidly engulf and destroy pathogens, playing a crucial role in the innate immune response.