![]() ![]() CD4+ T cells recognize antigens presented by Major Histocompatibility Complex (MHC) Class II and activate in order to kill intracellular microorganisms by releasing cytokines. The glycoproteins CD4 and CD8 are present on Th cells and Tc cells respectively. T cells are of two types: Th cells and Tc cells. T cells are distinguished from other lymphocytes due to the presence of T cell receptor. They are matured in the thymus from thymocytes. T cells are important in cell-mediated immunity. In CD8, the infecting viruses and tumor cells are destroyed directly.ĬD4 cells are responsible for the antigen presentation to B cells.ĬD8 cells are responsible for indirect phagocytosis. In CD4, Antigen presenting cells should be activated in order to kill intracellular microorganisms by releasing cytokines This affinity between the molecules keeps the cytotoxic T cell’s T cell receptor tightly bound together with the target cell during the activation of antigen specificity.ĬD4 cells recognize antigens presented by Major Histocompatibility Complex (MHC) Class II.ĬD8 cells only recognize antigens presented by MHC Class I.ĬD4 cells are situated on the surfaces of some immune cells like dendritic cells, T helper cells, macrophages, and monocytes.Ĭellulose is a linear structure with linear β glucose chains. Normally, the IgV, like extracellular domain of the type CD8-α, cooperates with the class I MHC molecules. It consists of an immunoglobulin variable (IgV) like extracellular domain connecting to the membrane by a stalk and an intracellular tail. The common types of CD8 are CD8-α and CD8-β. In order to facilitate the function, the CD8 forms a dimer which consists of a CD8 chain pair. Just like CD4, CD8 also belongs to the immunoglobulin superfamily. The CD8 are mainly located on the surface of cytotoxic T cells and cortical thymocytes, natural killer cells, and dendritic cells. Similar to the TCR, CD8 binds to the major histocompatibility complex (MHC) class I protein specifically. CD8 is also known as a co-receptor of the T cell receptor (TCR). Therefore, these CD4 become specific for antigens which are presented only by MHC class II.ĬD8 is considered as a transmembrane glycoprotein which functions in the immune system. CD4 interacts with β 2-domain of major histocompatibility complex (MHC) class II molecules with the help of D 1 domain. D 1 and D 3 are similar to immunoglobulin variable (IgV) domains while D 2 and D 4 are similar to the immunoglobulin constant (IgC) domains. These domains are situated on the extracellular surface of the respective cells. It consists of four immunoglobulin domains D 1 to D 4. CD4 belongs to the immunoglobulin superfamily just as other cell surface receptors. This Lck is needed to activate the molecular components of the signaling cascade of a T cell which is activated. CD4 possess a short cytoplasmic tail which consists of a special amino acid sequence that helps to initiate and communicate with tyrosine kinase Lck. CD4 protein is usually encoded by a gene called CD4 gene in humans. CD4 lies on the surfaces of some immune cells like dendritic cells, T helper cells, macrophages, and monocytes. Side by Side Comparison – CD4 Cells vs CD8 Cells in Tabular FormĬD4 is considered as a glycoprotein which plays a major role in the immune system. Similarities Between CD4 Cells and CD8 Cellsĥ. This is the key difference between CD4 cells and CD8 cells. CD8+ T cells only recognize antigens presented by MHC Class I and destroy infecting tumor cells and viruses directly. ![]() Due to the presence of two different types of glycoproteins, i.e., CD4 and CD8, on the cell surface of Th cells and Tc cells, they are referred to as CD4+ T cells and CD8+ T cells, respectively. T cells have two main categories: T helper (Th) cells and cytotoxic T cells (Tc). Since they mature in the thymus from thymocytes, they are referred to as T cells. In the context of cell-mediated immunity, T cells, generally referred to T lymphocytes, play an important role. ![]()
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