T lymphocyte and B lymphocyte

T lymphocyte and B lymphocyte 

 T lymphocyte

T lymphocyte develop from bone marrow-derived cells that migrate to the thymus .

They are essential to human defense against infectious organisms and some cancers. There are two main types of T-cells: helper T-cells and killer T-cells. Helper T-cells stimulate B-cells to make antibodies and help killer cells develop. Killer T-cells directly kill cells that have already been infected by a foreign invader. T-cells also use cytokines as messenger molecules to send chemical instructions to the rest of the immune system to ramp up its response. Activating T-cells against cancer cells is the basis behind checkpoint inhibitors, a relatively new class of immunotherapy drugs that have recently been federally approved to treat lung cancer, melanoma and other difficult cancers. Cancer cells often evade patrolling T-cells by sending signals that make them seem harmless. Checkpoint inhibitors disrupt those signals and prompt the T-cells to attack the cancer cells.

B lymphocyte

B cells, also known as B lymphocytes, are a type of white blood cell of the lymphocyte subtype.

 They function in the humoral immunity component of the adaptive immune system by secreting antibodies.

Additionally, B cells present antigens (they are also classified as professional antigen-presenting cells (APCs)) and secrete cytokines

 In mammals, B cells mature in the bone marrow, which is at the core of most bones.

 In birds, B cells mature in the bursa of Fabricius, a lymphoid organ where they were first discovered by Chang and Glick, (B for bursa) and not from bone marrow as commonly believed.

B cells, unlike the other two classes of lymphocytes, T cells and natural killer cells, express B cell receptors (BCRs) on their cell membrane

 BCRs allow the B cell to bind to a specific antigen, against which it will initiate an antibody response

While both are critical to the body's defense against disease and infection, T-cells and B-cells play very different roles. CART therapy and checkpoint inhibitors are examples of how researchers are using what they’ve learned about T-cells specifically in developing new cancer treatments. But as their differences and similarities show, both types of immune cells employ important natural defenses in helping the body fight cancer.

 

 Summary of T Lymphocyte and B lymphocyte 

topic	T lymphocyte	B lymphocyte
Origin	Bone marrow	Bone marrow
Mature	Thymus	Bone marrow
Location of mature cell	Mature cell present within the lymph node	Mature cell present out side the lymph node
Receptors	Bear TCR receptors	Bear BCR receptor
Viral antigens	Recognized viral antigens on the outside of infected cells	Recognized  antigens on the surface of bacteria and viruses
Life span	Long	Short
Type of immunity	Cell mediated immunity	Humoral or Antibodies mediated immunity
Types of active cell	Cytotoxic T cell , Helper T cell and suppressor / regulatory T cells and memory cells	Plasma cell and memory cells
Surface antigens	Lack of surface antigen	Have surface antigen
Secrete	Lymphokines	Antibodies
%	80% are T lymphocyte	20% are B lymphocyte
Site of infection	Move to the site of infection	Does not move to the site of infection
Tumor cell	Act against tumor cell or transplant	Do not act against tumor cell or transplant
Effect on immune system	Inhibitory effect on immune system	No inhibitory effect on immune system
Functions	·         Lyse virus infected cells and cancer cells ·         Provides immunity against most viruses and few bacteria ·         Aid B cell in antibodies production ·         Modulate immune response	Help eliminate free foreign invaders by enhancing innate immune responses against them Provide immunity against most bacteria and few viruses