About T4 Cell

Figure above show T-lymphocyte of human

What is T4 cell?

T4 cell is a helper T cell that displays the CD4 molecule on their surface protein. It’s called as T4 lymphocyte. They also have on their surface, epitope receptors called T-cell receptors (TCRs) that, in cooperation with the CD4 molecules, have a shape capable of recognizing peptides from exogenous antigens bound to MHC-II molecules on the surface of antigen-presenting cells (APCs) and B-lymphocytes. The TCR recognizes the peptide while the CD4 molecule recognizes the MHC-II molecule.

*T-CELL RECEPTOR: The receptor on the surface of T-lymphocytes that bind corresponding peptide epitopes of protein antigens bound to MHC molecules.

*CD MOLECULE: Cluster of Differentiation molecules are molecules serving as phenotypic markers for characterizing and distinguishing leukocyte subsets and functions. For example, CD4 molecules are found on the surface T4-lymphocytes and play a role in immune recognition.

*ANTIGENS: Antigens that enter from outside the body, such as bacteria, fungi, protozoa, and free viruses.

*MHC-II MOLECULES: Class II HLA molecules are made primarily by antigen-presenting cells (APCs, eg, macrophages and dendritic cells) and B-lymphocytes. They bind peptide epitopes from exogenous antigens to enable immune recognition by T4-lymphocytes.

*ANTIGEN-PRESENTING CELL (APC): APCs include dendritic cells, macrophages, and B-lymphocytes. APCs engulf and degrade protein antigens into peptide epitopes, bind those epitopes to MHC molecules, and place them on their surface where they can be recognized by the T-cell receptors of T-lymphocytes.

*B-LYMPHOCYTES:White blood cells that mediate humoral immunity (the production of antibody molecules). B-lymphocytes recognize epitopes of antigens by way of antibody molecules called sIg present on their surface and, after activation, eventually differentiate into antibody-secreting plasma cells.