Antigeneksponering

Antigeneksponering refers to the process by which an organism's immune system encounters an antigen. Antigens are typically foreign substances, such as components of bacteria, viruses, fungi, or parasites, that the immune system recognizes as non-self. This recognition is crucial for initiating an immune response.

When an antigen enters the body, specialized cells of the immune system, like dendritic cells and macrophages, can engulf and process it. These cells then present fragments of the antigen on their surface, a process known as antigen presentation. This presentation is essential for activating other immune cells, particularly lymphocytes such as T cells and B cells.

Upon encountering an antigen presented by antigen-presenting cells, T cells can become activated. Helper T cells, for example, play a vital role in coordinating the immune response by stimulating B cells and cytotoxic T cells. B cells, upon activation, can differentiate into plasma cells that produce antibodies specifically designed to neutralize or tag the antigen for destruction. Cytotoxic T cells directly kill infected cells that display the foreign antigen.

Repeated antigeneksponering can lead to immunological memory, where the immune system "remembers" the antigen. This allows for a faster and more robust response upon subsequent encounters with the same antigen, a principle underlying vaccination. The nature and strength of the antigeneksponering, along with the host's immune status, influence the type and effectiveness of the resulting immune response.