Tag: active and passive immunity

Plasma cells of B-lymphocytes are derived from the memory B-lymphocytes and are involved in the production of antibodies actively in the blood.

The B-lymphocytes are the types of immune cells that are involved in the humoral immune response. It means these cells are responsible for making antibodies in the bloodstream and destroy the antigen that infects the blood and tissues via blood. T-cells are responsible for cell-mediated immunity. They wipe out those pathogens that invade the tissues directly. B-cells can exist in two forms- Memory B-cells that are specified for a particular infection and Plasma B-cells that actively secrete antibodies. Plasma B-cells are derived from the memory B-cells whenever that specific antigen invades the blood second time.

The body's immune system is a normally occurring protective mechanism that helps the body defend itself against harmful agents. However, sometimes the immune system perceives normally harmless substances such as allergens or the person's own body tissues as harmful invaders and try to eliminate them. This inappropriate activation of the immune response is a major factor in allergic and auto-immune disorders.
Immunosuppressants are the drugs that suppress the immune to reduce the risk of rejection of foreign bodies with organ transplants or in auto-immune disorders.
B-cells are lymphocytes capable of producing antibodies and can capture circulating antigens. They are produced from stem cells in the bone marrow of adult mammals, liver of foetus and bursa of Fabricius in birds. The mature B-cells synthesize various types of antibodies which are displayed on their membrane surfaces, hence they are called immuno-competent B-cells. They are the cause of Humoral immunity.
T-cells are the lymphocytes that can recognize antigens if presented by antigen-presenting cells (APCs) by MHC molecules. They are the cause of cell-mediated immunity. Therefore, both B-cells and T-cells reveal the immunosuppressants on their surface and are part of the immune system.
Alpha cells are one of the types of cells in the Islets of Langerhans in the endocrine portion of the pancreas, which produces the hormone glucagon that is secreted in response to hypoglycemia.

• So the correct option is 'Both 1 & 3'.

B-lymphocytes form army of proteins called antibodies in response to pathogen in blood and are stimulated by antigen and T-helper cells. Therefore, B-lymphocytes provide humoral mediated immunity. T- lymphocytes provide cell mediated immunity. So, the correct option is 'B-lymphocytes'.

Acquired immunity is developed after birth. It is produced after getting exposed to antigens hence it is specific in nature. Acquired immunity creates immunological memory after an initial response to a specific pathogen, and leads to an enhanced response to subsequent encounters with that pathogen.

The T-lymphocytes originate in hematopoietic stem cells in the bone marrow and mature in the thymus. T-lymphocytes are responsible for humoral immunity. There are different types of T cells. They are listed below:

Cell mediated immunity is  macrophage providing an antigen for the T cells, so that the infected cells can be targeted

Adaptive immunity is often sub-divided into two major types depending on how the immunity was introduced. 'Naturally acquired immunity' occurs through contact with a disease causing agent, when the contact was not deliberate, whereas 'artificially acquired immunity' develops only through deliberate actions such as vaccination.

Acquired immunity or adaptive immunity develops following exposure to an antigen and is mediated by B lymphocytes or T lymphocytes or both, having a specific surface receptor for the same antigen.
Following are the characteristics of acquired immunity:

• Diversity: They can respond to millions of different antigens.
• Antibody specificity: Ability of the antibody to recognize the specific antigen (even antigen molecule differing by a single amino acid). The response is directed only towards the initiated pathogen.
• Immunologic memory: Once recognized and responded to an antigen, the system is able to respond more strongly to subsequent exposure even after many years.
• Discrimination between self and non-self: It can differentiate self-cells (host cells) from foreign cells and molecules. Only foreign particles are attacked. Failure of this discrimination results in auto-immune diseases.