T helper cells- TCR- CD4
binds MHC II –> signal transduction
T helper cells (also known as CD4+ T cells) are a type of lymphocyte that play an essential role in the adaptive immune response. These cells are able to recognize and bind to antigen-presenting cells that display foreign antigens on their surface. This binding allows the T helper cells to activate and orchestrate a range of immune responses to eliminate the invading pathogen.
The T cell receptor (TCR) on the surface of T helper cells is responsible for recognizing specific antigens presented by antigen-presenting cells. The TCR consists of two chains (alpha and beta) that are highly variable in amino acid sequence and can bind to a wide range of antigens. When the TCR binds to its specific antigen, it sends signals within the T helper cell that activate various immune responses.
CD4 is a co-receptor protein found on the surface of T helper cells. CD4 helps to stabilize the binding of the TCR to the antigen-presenting cell and promotes T cell differentiation and activation. CD4 also helps to regulate the T helper cell response by interacting with other cells in the immune system, such as macrophages and dendritic cells.
In summary, T helper cells express a TCR that recognizes foreign antigens presented by antigen-presenting cells, and this recognition is facilitated by the co-receptor protein CD4. Once activated, T helper cells orchestrate a range of immune responses to eliminate pathogens and protect the body from infection.
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