Question

Transplantation of tissues/ organs fails often due to non-acceptance by the patient's body. Which type of immune-response is responsible for such rejections?
A. Physiological immune response
B. Autoimmune response
C. Cell- mediated immune response
D. Hormonal immune response

Answer 1

Hint:You should understand, the immune system protects the body from possible harmful substances by recognizing and ultimately responding to antigens. Antigens are defined as, substances usually proteins on the surface of viruses, fungi, cells, or bacteria. Non-living substances like chemicals, drugs, toxins, and foreign particles (such as a splinter) can also be called antigens.
Remember, the immune system recognizes and tries or destroys substances that contain antigens.

Complete answer:
Humoral immunity is antibody-mediated immunity and in this, with assistance from helper T cells, B cells differentiate into plasma B cells which can make antibodies against a specific antigen. The humoral immunity basically deals with antigens from pathogens which freely circulate, or are outside the infected cells. The antibodies made by the B cells bind to antigens, neutralize them, or cause lysis or phagocytosis. Whereas, cellular immunity is mediated by T lymphocytes and the pathogen's antigens are expressed on the surface of the cell or on an antigen-presenting cell. Helper T cells will give cytokines that help to activate T cells which bind to the infected cells - MHC-antigen complex, and differentiate the T cell into a cytotoxic T cell. Now, the infected cell undergoes lysis.
Now understand, that Transplantation of tissues or organs increases the risk of rejection because it is recognized by the immune cells as non-self. Note, the cell mediated immune response is majorly involved in to reject transplanted organs. The cell mediated immune response, basically involves T cells that release cytokines to foreign objects in response.

Additional information:
Always keep in mind, autoimmunity is the immune response system of an organism against their own healthy tissues and cells. All the disease that results from such an immune response is called an "autoimmune disease".
Therefore, the correct answer is option C.

Note:- You should understand, the system of cell mediated immunity, is the host primary or first response against virus and invasive bacteria, that give rise to intracellular infections. It’s essential to fight against and destroy cancerous cells. Note it, the cell-mediated immune system plays a role in the rejection of or graft tissue organ transplants.