Describe all the roles of tcells in specific immunitySolutio

Describe all the roles of t-cells in specific immunity.

Solution

There are two types of lymphocytes depending on the site of production and maturation. The lymphocytes are produced by the precursor cells from the stem cells in the bone marrow. The development and learning of function of lymphocytes is a process known as developing immune competence. Some precursor cells migrate from bone marrow to thymus gland and undergo development and maturation. These specific lymphocytes are called T lymphocytes (Thymus dependent lymphocytes).

Some lymphoid cells remain within the bone marrow to differentiate and develop into specific type of lymphocyte called B lymphocytes (bone marrow dependent lymphocytes).

When the antigen enters the body the immune system is activated. The antigen presenting cells like macrophages bind to the antigen and are presented to T helper cells by class I MHC molecules and class II MHC molecules present the antigen to T cytotoxic cells and natural killer cells that degrade the antigen.

In humoral immune response, The T_H2 helper cell along with class II MHC molecule attached to CD4 or CD8 along with antigen binds to T cell receptor that is recognized by IL 4 and B7 cells co- stimulate the memory T_H2 cell to produce antibody against the antigen accomplishes the three cell interaction.

The T_H cells pre-committed to neutralize antigen would recognize the antigen through the carrier epitope molecules and through carrier determinant Class II molecules by T cell receptors. Thus, clonal selection and T cell B cell cooperation is important in generating an immune response. B cell and T cell response towards an antigen depends on hapten and carrier concept. T cells recognize only peptides associated with class II MHC molecules by T cell receptors.

The T lymphocytes possess specific receptors for binding of antigen. Once, the antigen is found on the T cell receptor it is recognized by an antibody and is neutralized.