Helper T cells

Helper T cells are a type of T cell that play an important role in the immune system, particularly in the adaptive immune system. They help the activity of other immune cells by releasing T cell cytokines. These cells help suppress or regulate immune responses. They are essential in B cell antibody class switching, in the activation and growth of Cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages.

Overview

Mature helper T cells express CD4 protein on their surface, which enables these cells to interact with MHC class II molecules on antigen-presenting cells. This interaction can produce a costimulatory signal necessary for T cell activation.

Types of Helper T cells

There are different types of helper T cells, each with a different function:

• Th1 cells: These cells are involved in cell-mediated immunity, which is the immune response that involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen.

• Th2 cells: These cells are involved in humoral immunity, which is the immune response that involves the activation of eosinophils, IgM, and IgE antibodies, and the release of cytokines in response to an antigen.

• Th17 cells: These cells play a crucial role in maintaining mucosal barriers and contributing to pathogen clearance at mucosal surfaces.

• Tfh cells: These cells help in the process of class switching, in which the constant region of the antibody heavy chain changes, but the variable region of the heavy chain stays the same.

• Regulatory T cells: These cells help regulate or suppress other parts of the immune system to prevent immune disorders like autoimmunity.

Role in Disease

Helper T cells play a crucial role in the immune system, and their dysfunction can lead to several diseases. For example, the HIV virus, which causes AIDS, primarily infects helper T cells, leading to a significant decline in their numbers and resulting in a weakened immune system.

See Also

• Immune system
• T cell
• B cell
• Cytokine
• Antigen-presenting cell
• MHC class II
• CD4
• HIV
• AIDS

Helper T cells Resources
Latest articles Most recent articles Ongoing trials	Wikipedia