Question

• How can the immune system orchestrate protection from disease without killing us in the process

• IQ4: Homeostasis: A balance of the good and bad

  B- and T-lymphocytes are derived from bone marrow- derived lymphoid precursors. Before maturation, naive T-lymphocytes (T-cells) must pass through the thymus where they undergo positive and negative selection. A tumour encounters the immune system frequently during its progression from a neoplasia to carcinoma, which can often take several years. There are a number of host mechanisms that are exploited by the tumour to deceive and subvert the immune response. One exploit drives the production of regulatory T-lymphocytes (T-reg cells), which are able to kill activated cytotoxic T-lymphocytes (T-cells) and dendritic cells (DCs), which are able to kill tumour cells and prevent tumours from forming. The gut is colonised by a wide variety of foreign microorganisms which live in a symbiotic relationship with the host. Normal gut immunity is maintained with a balance where good bacteria are tolerated while the immune response to toxic bacteria is restricted to the site of infection and proportional to the extent of infection.

  You might like to consider:

  • What factors influence immune system balance?
  • How does the immune system learn what is ‘self’ and ‘non-self’ and what role does a thymus perform?
  • What is immune tolerance, and how does the immune system regulate T-cells from killing ‘self’?
  • What types of immune cells are there, how are they different, and how do they stop a bacterial infection?

Answer 1

{A} Several factors like :- 1) Sleep

2) Diet

3) Hygiene

4) Stress

5) Environmental factors. Apart from all of these factors hygiene is the most important one .

{B} Immune system learns what is self and non-self by the action of recognition .The immune system can distinguish between a foreign molecule and a self molecule ,because all self or local cells have antigens (identifying molecules) on their surface. Thymus have a function of providing an environment for the development of T- cells from precursor cells to be self tolerant.

{C} Immune tolerance is nothing but a state in which there will be no response given to a specific antigen or a group of antigen to which a person normally gives a response.Its a condition where the immune system is absent.Its also known as immuno-tolerance, The T-cells usually select the those cells with a potential to recognize self MHC + foreign peptides and delete the cells with a potential to recognize self MHC + self peptides.

{D} Lymphocytes,Neutrophils , Monocytes are the 3 types of cells of immune system.

Lymphocytes are white blood cells which are made up of bone marrow they defend the body from foreign substances like viruses, bacteria,cancer cells. Neutrophils are a type of white blood cells which help in healing the damaged tissues and also help in resolving infections. Monocytes are the largest of leukocytes , they can be differentiated into macrophages and myeliod lineage dendritic cells which influence the process of adaptive immunity , The antibodies directly bind to toxins produced by the bacteria and try to supress them or the antibodies directly neutralize the pathogen by attacking them directly and stopping them to infect a normal body cell .