SURFACTANT PROTEIN A (SP-A) IS BELIEVED TO PLAY A ROLE IN

• A. The innate immune system of the lung ✓
• B. Type 2 cell hyperplasia
• C. Alveolar development
• D. Type 2 cell function

Surfactant protein A (SP-A) is a crucial component of the innate immune system in the lungs. SP-A is a member of the collectin family, which plays a significant role in host defense against pathogens in the respiratory tract. It is primarily produced by alveolar type II cells and acts as an opsonin, enhancing phagocytosis of microorganisms by alveolar macrophages. SP-A also regulates inflammatory responses and modulates immune cell functions within the lung.

In other words, SP-A acts as a pattern recognition molecule, recognizing pathogens such as bacteria, viruses, and fungi. By binding to these pathogens, SP-A helps to opsonize them, facilitating their clearance by phagocytic cells like macrophages and neutrophils. Additionally, SP-A can modulate inflammatory responses in the lung, contributing to host defense mechanisms against infections.