How do macrophages contribute to the immune response?

Macrophages play a crucial role in the immune response by engulfing pathogens and presenting antigens to other immune cells. This process is vital for initiating and shaping the adaptive immune response. When macrophages encounter a pathogen, they perform phagocytosis, whereby they engulf and digest the pathogen. Following this, they process the pathogen's proteins into smaller peptide fragments and present these fragments on their surface through a molecule called major histocompatibility complex (MHC). This antigen presentation is essential for the activation of T cells, which further orchestrates an immune response tailored to the specific pathogen.

This dual role of macrophages—acting as both phagocytes that eliminate pathogens and as antigen-presenting cells that activate other immune components—highlights their importance in linking the innate and adaptive immune systems. Without this function, the immune system would be less effective at responding to infections and developing a long-lasting immunity.