Adaptive Cell-mediated Immunity

Adaptive immune responses are caused by the white blood cell or t lymphocytes , these adaptive responses are further divided into two classes: the cell mediated immune response and the antibody mediated response. The responses are caused by cells known as the B lymphocytes and T lymphocytes . B lymphocytes help in generation of antibodies or the immunoglobulins while the T cells help in production of these antibodies .These antibodies or immunoglobulins move in and around the bloodstream and attaches to the foreign particles leading to their  inactivation by blocking their binding sites.  This further leads to destruction of the antigens . while in the cell-mediated immune responses the activated T cells react directly with the foreign antigen that is present  on the host cell. The T cell  can  kill a virus-infected host cell and thereby  eliminate the infected cell before  replication .  Also, they can in  some other cases produce signal molecules that activate macrophages to destroy the invading microbes that the T cells have phagocytosed.

 Cell mediated adaptive immunity

Cellular immunity  is witnessed in cells that are infected earlier  and involves the  T lymphocytes. Cell does not depend on antibodies for its adaptive immune functions.it is dependent on the  mature T cells, macrophage and cytokines cells that are involved; the cell mediated response recognises the intracellular targets with the help of the MHC class I proteins .

Cell-mediated immunity is involved in case of intracellular invaders. T cells can also recognise cancerous cells as well. The  antigens in this case  are present on the cell surface or on an antigen-presenting cell. Helper T cells  in this process release cytokines that help activation of the T cells  that further attach or bind to the infected cells MHC-antigen complex .This finally results  in  formation of cytotoxic T cells. The infected cell then undergoes lysis. Lymphocytes involved in cell-mediated immunity include naïve T cells, helper T cells, killer T cells, and macrophages

Difference between cell mediated immunity and humoral immunity

The major points of distinction between the cell mediated immunity and humoral immunity are listed below as follows..

• Humoral immunity  is a type of antibody mediated response  while cellular immunity is a  T – cell mediated response .In humoral immunity the site of activity is the extracellular fluids while in the case of cell mediated immunity the site of activity is the tissue having the antigen.
• In the case of humoral immunity, the main cell types that are involved are the B cells or the B lymphocytes while in the case of cellular immunity the main types of cells that are involved are the T cells  or the T – lymphocytes.
• In case of humoral immunity, the response after the encounter with the antigen is fast and quick while in the case of cell mediated immunity the response to the foreign particle or the antigen is a slow process or response prior to detection.
• In case of the humoral immunity the target pathogen or the antigen are the extracellular  pathogens while in the case of cellular immunity the target pathogens are present inside the cell hence intracellular pathogens are targeted,The difference between the mode of action of the two adaptive immunity types is that in the case of humoral immunity the antibody mediated destruction and neutralisation of the foreign particle takes place while in the case of cellular immunity the mode of removal of the foreign particle is programmed cell death accompanied by lysis.
• Also, there’s a difference in the MHC protein involved in the two types , in the case of cellular immunity the MHC class II protein is involved while in the case of antibody mediated immunity MHC class I protein is involved.

Conclusion

Adaptive immune responses are caused by the white blood cell or  lymphocytes , these adaptive responses are further divided into two classes: the cell mediated immune response and the antibody mediated response. The responses are caused by cells known as the B lymphocytes and T lymphocytes .  B lymphocytes help in generation of antibodies or the immunoglobulins while the T cells help in production of these antibodies . the antibody mediated response depends on the antibodies while the Cell-mediated immunity is depended on the mature T cells, macrophages, and the release of cytokines .Lymphocytes involved in cell-mediated immunity include naïve T cells, helper T cells, killer T cells, and macrophages. The main points of distinction between the two types of immunity are :humoral immunity is antibody mediated while cellular is T cell mediated Class I proteins in cellular while MHC class II in the case of antibody mediated humoral ,intracellular invaders are targeted in cell mediated while extracellular by the humoral immunity cells are involved in humoral while T cells in the case of cellular immunity.