Which cell type helps begin the immune response by presenting antigens?

Antigen-presenting cells (APCs) play a crucial role in initiating the immune response by capturing, processing, and presenting antigens to T lymphocytes. These cells, which include dendritic cells, macrophages, and B lymphocytes, display the antigens on their surface in association with major histocompatibility complex (MHC) molecules. This interaction is essential for the activation of naive T cells, which recognize the presented antigens and subsequently differentiate into various T cell subsets that coordinate the immune response.

The importance of antigen presentation lies in its ability to bridge the innate and adaptive immune systems. When APCs encounter pathogens, they not only present the antigens but also provide necessary co-stimulatory signals that are required for T cell activation. This process ensures that the immune response is tailored specifically to the encountered antigens, enhancing the effectiveness of the immune system in fighting infections.