Principle cells of the immune system - Essay Example

PRINCIPAL CELLS OF THE IMMUNE SYSTEM PRINCIPAL CELLS OF THE IMMUNE SYSTEM The immune system is generally in place to ensure that the body is able to fight against disease causing organisms that enter the body. But for the immune system to function very effectively, there are a number of cells and tissues that come together to play principal roles. Even though the cells that make up the immune system are many, Zen and Parkos (2003) found that the function that most of these play overlap others.

This makes it important to categorise the principal cells into their functional groups to distinguish them according to the roles they play in the immune system to facilitate immune response. Three of such principal cells of the immune system are lymphocytes, antigens, and effector cells. Below, brief descriptions of the roles of these three cells in immune response are discussed.Lymphocytes have been noted to be cells that emanate from stem cells within the larger immune system. As far as immune response is concerned, the lymphocytes take charge of the adaptive response (Guermonprez et al., 2012). For this to happen, there are a series of functional activities that come together.

Working together with specific receptors, the lymphocytes function towards the recognition of specific antigens that enter the body. Consequently, the effect of antigens in the body would be hampered if the lymphocytes are not functioning properly. Bryant, Trinder and Curtis (2004) also noted that one the lymphocytes emanate from the stem cells, they go on to form three different populations of cells which are B cells, T cells and natural killer (NK). Of the three however, it is the B and T cells that take part in the adaptive immunity as NK cells function as innate immunity.

The B cells for example produce antibodies, whiles the T cells engage in cell-mediated immunity (Guermonprez et al., 2012).The second principal cells are the antigen presenting cells, which have the core role of aiding the lymphocytes to undertake the adaptive response. In some cases therefore, the antigen presenting cells are considered to be also responsible for adaptive response. The antigen presenting cells function by bringing antigens to the lymphocytes. Writing on the anatomy of the immune system, Zen and Parkos (2003) indicated that the location of the antigen presenting cells (APC) makes it very convenient for it to play its role.

This is because these APCs are found in the periphery. From this location, they are able to examine the tissues to identify antigens. One major difference between the function of the lymphocytes and APCs is that whereas lymphocyte locates very specific antigens, the APCs take advantage of their receptors to identify very large array of antigens (Bryant, Trinder and Curtis, 2004). Once the identification of the array of antigens is done, the APC stimulate molecules to undertake the migration of the antigens into the lymph for the lymphocytes to take over their role.

Effector cells are the third group of cells that come together to complete the list of principal cells of the immune system. The function of these cells in immune response is very direct as they perform the killing of microbes whenever an adaptive response has been effected (Guermonprez et al., 2012). It is for this reason that the effector cells have been said to be dependent cells, taking their functions from the outcome of what happens with adaptive response. But an important indication is that unless effector cells are present, the killing of microbes cannot be completed.

The effector cells comprise other forms of cells such as activated lymphocytes and leukocytes. In their raw states however, the lymphocytes never become activated to kill microbes. Once activated, both T cells and NK cells kill different forms of endocytosed microbes and other infected cells.ReferencesBryant PA, Trinder J and Curtis N (2004). "Sick and tired: Does sleep have a vital role in the immune system?". Nature Reviews Immunology 4 (6): 457–67.Guermonprez P, Valladeau J, Zitvogel L, Théry C and Amigorena S (2012).

"Antigen presentation and T cell stimulation by dendritic cells". Annual Review of Immunology 20 (1): 621–67.Zen K and Parkos CA (2003). "Leukocyte-epithelial interactions". Current Opinion in Cell Biology 15 (5): 557–64.