Question

Describe what happens in deficiencies of B and T cells. Please include description of the role of B and T cells,what causes deficiencies in these cell lines,explain why individuals with B-cell deficiencies more prone to bacterial infections, and why people with T-cell deficiencies are more prone to viral infections, and give examples of common infections associated with B-cell deficiencies and common infections associated with T-cell deficiencies.

Answer 1

Firstly we will talk about T-cells-

• One of the types of lymphocyte, whose maturation occurs in thymus, while originating in bone marrow.They are helpful in identifying viruses and microorganisms by the antigens present on their surface.
• T-cells originate in bone marrow and mature in the thymus.They are situated inside the lymph nodes, that is in the lymphoid sheath of spleen and cortex of the lymph nodes.
• They have the T-cell receptor also known as TCR.They have the long life span.T-cells occupy 80% of the total lymphocytes present in the blood.
• Cytotoxic T-cells, helper T-cells and suppressor T-cells are the main types of T-cells.They are involved in the cell mediated immunity.Tcells secretes lymphokines as they lack surface antigens they identify viral antigens outside the infected cells.T cells instantly move to the infected site and also have the inhibitory effect on the immune system.T cells work against the tumour cell or any transplanted organ, protect and fight against the pathogens like fungi, virus which enters the body this is the reason why people with T-cell deficiencies are more prone to viral infections.

According to the question the next thing is about B cell-

• B cell is another type of lymphocyte, whose maturation and origination is in bone marrow only in mammals, while in birds it is in bursa of fabricus.B Cell can recognise the antigen i.e foreign body and produce antibodies against it.
• B cells originate in bone marrow and are situated outside the lymph nodes that is in the respiratory tract, spleen, gut, germinal centers, in the medular and sub capsular cords of the lymph nodes.
• They have the B cell receptor , also known as BCR.They have short span of life.They contain surface antigens.
• Bcells occupy remaining 20% of the total lymphocytes present in the blood.Memory cell and plasma cell are two types of BCell.
• The main role of BCells they are involved in humoral mediated immunity or antibody mediated immunity, Bcells identifies the antigens on the surface of virus and bacteria as they surface antigens.They fight and protect the body from the bacteria and virus that enters the bloodstream, this the reason why people with BCells deficiency are prone with bacterial infection.

What causes deficiencies of T cell and BCell?

​​​​​B cell- Humoral immune deficiencies are conditions which cause impairment of humoral immunity, which can lead to immunodeficiency, it can be mediated by insufficient number or function of BCells, the plasma cells they differentiate into, or the antibody secreted by plasma cells.

T cell deficiency is a deficiency of T cells, caused by decreased function of individual T-cells, it causes an immunodeficiency of cell mediated immunity.

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