The macrophage presents the antigen to the helper-T cell, which responds by producing the cytokines that stimulate B cells to multiply and release antibodies. Helper-T cells, however, can only identify viruses engulfed by special cells called macrophages. Killer-T cells have the ability to recognize and destroy infected cells in the body. T-cells are classified as killer-T cells, helper-T cells, or suppressor T-cells. Usually, remnants of these complexes are removed from the body by a garbage disposal system that involves the spleen. These antibodies then circulate in the bloodstream so that when they encounter the antigen again, they bind to it, forming a complex that is then acted on by other cells of the immune system in an effort to destroy the invader. Cytokines then cause B-cells to multiply, and some of these B cells turn into plasma cells that secrete antibodies (immunoglobulins). When a T-cell recognizes a specific antigen, it binds to the substance and produces chemicals called cytokines. Lymphocytes include cells called B-cells and T-cells that are responsible for flagging and fighting infections in healthy individuals.Īntigens are substances that elicit the response of T-cells and B-cells in the body. T-cells, B-cells, and AntibodiesĪ group of white blood cells called lymphocytes plays a key role in the human immune response. ![]() Certain cells and processes of the immune system have been identified as playing a role in lupus. This phenomenon is similar to “friendly fire” and can cause permanent scarring that ultimately jeopardizes the function of certain organs and systems in the body. ![]() However, in lupus and other autoimmune diseases, the immune system begins to recognize and attack “self.” In other words, the cells of the immune system begin to injure the body’s own tissues. Usually, the immune system develops only to act upon foreign substances, and immune system cells that try to combat cells of the body are weeded out during the development process. This attracts other immune cells such as eosinophils and basophils to the site, which is of particular importance in combating parasitic infections.The immune system is an elaborate network of cells, tissues, and organs that helps to protect the body from invaders (bacteria, viruses, fungal infections, and parasites). They express high-affinity Fcε receptors to encourage IgE binding that leads to degranulationof these cells. Mast cells are a particularly good example. This restricted distribution pattern also plays a huge role in conferring the type of response produced. Not only does binding to these various receptors lead to different outcomes, but the expression of these receptors on particular cell types also helps to further hone the response. There are various subtypes of these receptors to increase the specificity of this response for example, Fcγ for IgG, Fcε for IgE, Fcα for IgA and Fcα/µ for IgM/IgA. The special functions of each antibody are therefore partially determined by which Fc receptor they bind to. Most immune cells carry Fc receptors, which bind this portion of the antibody and therefore react to the presence of the antigen through a variety of mechanisms. This is the area of the antibody that interacts with other immune cells, and hence has a huge impact on the effect on the resulting response. Well, as you can see from the picture above, the constant regions of the heavy chain come together to form the Fc portion of the antibody. We’ve already discussed the fact that the functional properties of an antibody are conferred by the constant regions of the heavy chain, whilst the antigen binding ability is determined by the paratopeproduced by the variable light and heavy chain regions together.īut what does the heavy chain actually do?
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