Antigénprezentáció

Antigen presentation is a crucial process in the immune system that involves the display of foreign substances, known as antigens, on the surface of cells to activate an immune response. This process is primarily carried out by antigen-presenting cells (APCs), such as dendritic cells, macrophages, and B cells. Antigen presentation occurs in two main forms: major histocompatibility complex (MHC) class I and MHC class II presentation.

MHC class I presentation is involved in the recognition of intracellular pathogens and cancer cells. In this process, APCs internalize the antigen and degrade it into peptides. These peptides are then loaded onto MHC class I molecules, which are transported to the cell surface. The resulting MHC class I-peptide complex is recognized by cytotoxic T cells, leading to the activation of an immune response against the infected cell.

MHC class II presentation is involved in the recognition of extracellular pathogens and is typically associated with the activation of helper T cells. In this process, APCs internalize the antigen and degrade it into peptides. These peptides are then loaded onto MHC class II molecules, which are transported to the cell surface. The resulting MHC class II-peptide complex is recognized by helper T cells, leading to the activation of an immune response against the pathogen.

Antigen presentation is a highly regulated process that involves the coordinated action of various molecules and signaling pathways. Dysregulation of antigen presentation can lead to immune disorders, such as autoimmune diseases and immunodeficiency. Understanding the mechanisms of antigen presentation is therefore essential for the development of new therapies for immune-related disorders.