T4 Lymphocytes

What are T4 Lymphocytes?T4 lymphocyte is a subtype of lymphocytes. T4 lymphocytes are subgroups lymphocytes, present in the WBC (white blood cells) in the immune system of all vertebrates. White blood cells are responsible for improving our immunity system and creating substances that can fight against the harmful foreign substances and protect our body. All types of lymphocytes are responsible for this functioning of the WBC.

Lymphocytes are of 3 types:

• The natural killer cells
• The T- cells
• The B- Cells

T4 lymphocytes are a further classification of T- cells. T4 Lymphocytes, on the other hand, helps in producing unique TCR (T- Cells Receptors) and CD4 cells. TCRs are protein molecules, which are formed on the outer membrane of the lymphocytes, in response to antigens like, bacteria, virus, toxins, cells of transplanted organs and foreign blood cells, to protect our body. T4 lymphocytes are also called helper T- cells.

Therefore the roles of T4 lymphocytes are:

• Protect our immune system
• Produce TCR
• Produce CD4 cells
• The CD4 cells and the TCR are together responsible for fighting any kind of diseases.
• Save us from harmful diseases.

How do T4 Lymphocytes function?

The human immune system cannot predict what kind of antigens it may encounter. Therefore, the T4 lymphocytes, in the white blood cells, are modified in a way so that it can respond to any type of antigens, and produce any type of antibodies and cytotoxic granules in reaction to that. In case they are insufficient to fight the external bodies, they signal the other cells of the immune system. We, on the other hand, suffer from a disease, when all these cells cannot fight these external antigens, because of the powerful presence of the latter. The fighting cells it produces are very responsive, and are created keeping the need of the hour in mind. The TCR and CD4 cells that are produced are never the same for all antigens. A different genre of these substances is produced in reaction to every different antigen that our body encounters.

The T4 Lymphocytes get genetically activated by gene splicing reactions or gene translocation, to produce TCR. TCRs of most T4 Lymphocytes can identify peptide epitopes from protein antigens. These protein antigens are produced by our own body, with the help of major histocompatibility complex molecules (MHC). Some of the peptide epitopes in the harmful antigens are recognized by MHC-I and others are recognized by MHC-II molecules.

In HIV patients, T4 lymphocytes counts are normal in the asymptomatic stage. However, it decreases a lot as the disease progresses. As the number of T4 lymphocytes decreases, our immunity system invariably fails.

Development of T4 lymphocytes:

All lymphocytes are developed during the process of haematopoieses, within our bone marrow. They originate from common lymphoid progenitor. The process of lymphocyte formation is called lymphopoiesis. When the T-cells are formed, they create their permanent seat in an organ called thymus. However, they gradually circulate into other body parts like the spleen and Lymph nodes (Lymphoid organs). As they circulate into the lymphoid organs, they start policing for foreign harmful organisms or antigens.

Thus, T4 lymphocytes and all other lymphocytes are an integral part of our immune system when a person contract HIV, the T4 lymphocytes suffers the most that takes a toll on our immunity.