what type of cell recognizes cells that have been infected by viruses because the infected cells have viral proteins on their surfaces?
The type of cell that recognizes cells infected by viruses due to the presence of viral proteins on their surfaces is the cytotoxic T cell (also known as a killer T cell or CD8+ T cell). These specialized immune cells play a critical role in the body's defense against viral infections.
To understand how cytotoxic T cells recognize infected cells, we need to dive into the basics of the immune response:
1. Infection by a virus: When a virus enters the body and infects a cell, it hijacks the cellular machinery to replicate itself.
2. Viral protein production: As part of the replication process, the infected cell starts synthesizing various viral proteins, including those located on the cell surface.
3. Antigen presentation: Infected cells, under the influence of viral infection, display small fragments of viral proteins on their cell surface. These fragments are called antigens and act as signals to alert the immune system.
4. Activation of cytotoxic T cells: Cytotoxic T cells have a unique ability to recognize these viral antigens presented on the surface of infected cells. To achieve this, they possess T cell receptors (TCRs) on their surface, which are proteins capable of recognizing specific antigens.
5. Binding and killing: When a cytotoxic T cell encounters an infected cell displaying viral antigens, the TCRs on its surface bind to these antigens, resulting in the activation of the cytotoxic T cell. This binding triggers the release of specific proteins called cytotoxic granules, which contain powerful enzymes that can destroy the infected cell, effectively eliminating the source of the viral infection.
In summary, cytotoxic T cells are able to recognize cells infected by viruses because they have specific T cell receptors that can bind to viral antigens presented on the infected cell's surface. This recognition triggers the immune response, leading to the elimination of the infected cell.