B- LYMPHOCYTES (TYPES AND IT'S FUNCTIONS).pptx

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1. B- LYMPHOCYTES ( B- CELLS) M. CHATIYAA I – M.Sc MICROBIOLOGY DEPT. OF MICROBIOLOGY SACRED HEART COLLEGE

2. IMMUNE SYSTEM Unique arrangement of different cells, tissues and organs working together as a defense against infection and diseases. Scientific study of Immune system called Immunology. Lymphoid cells, Myeloid cells and Erythroid cells are the cells of Immune system.

3. CELLS OF IMMUNE SYSTEM LYMPHOID CELLS/ LYMPHOCYTES MYELOID CELLS ERYTHROID CELLS B - CELLS/ B - LYMPHOCYTES T – CELLS/ T- LYMPHOCYTES NATURAL KILLER CELLS/ NK CELLS MONONUCLEAR PHAGOCYTES ANTIGEN PRESENTING CELLS GRANULOCYTIC CELLS MONOCYTES MACROPHAGES NEUTROPHILS EOSINOPHILS BASOPHILS MAST CELLS PLATELETS ERYTHROCYTES DENDRITIC CELLS/ LANGERHANS CELLS

4. LYMPHOCYTES Otherwise called as Lymphoid cells. Help the body remember previous invaders and recognize them if they return to attack again. Begin their life in Bone marrow. Some stay in the marrow and develop into B- Lymphocytes; others travel to the Thymus and become T- Lymphocytes.

5. B- LYMPHOCYTES B- Lymphocytes / B- cells protect from infection by making proteins called antibodies. Hence, they are well known as Antibody generators . When Immune system detects threat like a Bacteria or Virus has entered body, B- cells produce antibodies to fight against the invader.

6. TYPES OF B - CELLS PLASMA CELLS Otherwise called Plasmacytes or Effector cells. Plasma cells release antibodies in response to antigens. Once B- cells become a mature Plasma cells, it can release upto 2000 antibodies per second . They have shorter lifespan than memory cells.

7. MEMORY CELLS Memory cells remember particular antigens so, if they appear in body in future, immune system can mount a defense quickly. While plasma cells fight antigens by producing antibodies, memory cells help immune system fight in future . Exmple ; Vaccines.

8. FUNCTIONS OF B - CELLS Once B- cells spot antigen, they begin secreting antibodies . Antibodies are special proteins that lock on to specific antigens. Each B cell makes one specific antibody . For instance, one might make an antibody against the bacteria that causes Pneumonia, and the other might recognize the common cold virus.

9. The B- cells respond to antigens in two ways namely; Primary immune response. Secondary immune response. PRIMARY IMMUNE RESPONSE When an antigen attaches to a receptor, B- cells are stimulated. Some B- cells change to memory cells, others to Plasma cells. Plasma cells make an antibody specific to a particular antigen. Production of enough specific antibody can take several days.

10. SECONDARY IMMUNE RESPONSE If B- cells encounter the same antigen again, the memory cells remember it and they change to plasma cells and quickly produce the correct antibody.

11. NORMAL RANGE OF B- CELLS Normal range of Lymphocytes in adults is between 1000 – 4800 in every microliter of blood. Approximately 10% - 20% of Lymphocytes are B- cells. High or low B-cells may lead to any disease condition.

12. AUTOIMMUNE DISORDERS Sometimes, B- cells make antibodies in response to antigens associated with body’s healthy cells. When this happens, the antibodies attack the healthy cells , and the condition called Autoimmune diseases. Examples, Multiple sclerosis, Rheumatoid arthritis, Type 1 diabetes.

13. Several cancers are associated with abnormal B-cell development namely; Acute Lymphocytic Leukemia. Chronic Lymphocytic Leukemia. B-cell Lymphoma. Multiple myeloma.