Question

Identify the three signific events that occur in the liftime of a lymphocyte.

Answer 1

Lymphocytes are a type of white blood cells which consist of B Lymphocytes and T lymphocytes and natural killer cells. These cells originate from the multipotent hematopoietic stem cells (HSCs) in the bone marrow. The T cells are responsible for  cell-mediated immunity, b cells participate in humoral immunity and natural killer cells are a part of innate immune system .

The three significant events that occur in the lifetime of a lymphocyte are

1.Formation and maturation ; The formation of lymphocytes is known as lymphopoiesis. It takes place in the bone marrow. All types of lymphocyte originate from common lymphoid progenitor and then divided into different type of cells. The B cells mature in the bone marrow itself but the T cells migrate to thymus for maturation. They enter into peripheral vascular system following maturation.
2. Activation of lymphocytes ; Lymphocytes are activated during invasion of a stranger organism into the body like bacteria, virus etc.
3. Effector response (action of lymphocytes to eliminate an antigen) ; The B cells produce antibodies against the invaded organism. Some of the T cells become helper T cells and produce cytokines which direct the immune response while some other T cells become Cytotoxic T cells and produce power full enzymes which kills the invading organism by killing them. Some T cells become memory T cells which helps to respond immediately in future towards the same infection.