General description of immune system
- 1. General description of Immune System from modern expect Presented by Dr Shahnaz Bano Department of Mahiyatul Amraz Govt Tibbi College, Patna Under supervision of Asst Prof. Dr Md. Shamim Akther Department of Mahiyatul Amaraz Govt Tibbi college, Patna
- 2. 1. Immune System 2. Antigen 3. Formation Immune cells 4. Myeloid cells 5. Lymphoid cells 6. Antigen presenting cells 7. Proteins of immune system 8. Organs of immune system 9. Types of immunity 10. Receptors Table of Content
- 3. What is the Immune System? • The immune system is a complex network of cells and proteins that defends the body against infection. • The immune system keeps a record of every microbe it has ever defeated so it can recognize and destroy the microbe quickly if it enters the body again. • Abnormalities of the immune system can lead to allergic disease, immunodeficiencies and autoimmune disorders.
- 4. Parts of Immune System PROTEIN ORGANS CELLS
- 5. Properties of Immune System • Complex process • Limits pathogens proliferation • Provide protection • Create Immune response • Helps cells communicate with each other • Self and non self distinction
- 6. What is Antigen Any factors or agents that can enter the body and create an immune response are called antigen.
- 7. Types of Antigen Exogenous • Bacteria • Virus • Parasites • Fungi Endogenous • Faulty proteins • Nucleoprotein • Infected cells • Cancer cell Properties of Antigen • Foreignness • Proteineous in nature • Size- 14 kilodalton to 600 kilodalton • Epitope • Host pathogen co-evolution
- 9. Formation of Immune cells • Immune cells are produced by hematopoietic stem cell in bone marrow • Hematopoietic stem cells are self-renewing and reside in the medulla of the bone ( bone marrow ). • HSCs are divided into two main lineages, lymphoid progenitor cells or myeloid progenitor cells. • Lymphoid progenitor cells differentiate into B and T cells and NK cells. • Myeloid progenitor cells differentiate into myelocytes (granulocytes and monocytes) or non-leukocytes such as erythrocytes and megakaryocytes (which produce platelets).
- 10. HSC Myeloid cell Granulocytes Neutrophils Eosinophils Basophils Mast cell Antigen presenting cells Monocyte Macrophage Dendritic cells Lymphoid cell T lymphocytes Helper cell Cytotoxic cell B Lymphocytes Memory cells Plasma cells NK cell
- 11. Myeloid cells • Most abundant type of granulocytes • First Line Of Defense in bacterial infection • Make up 40% to 70% of all WBC • Multilobes nucleus • Phagocytic cell • Release inflammatory molecules like cytokines • Highly motile • Antimicrobial function • It helps to regulate adaptive immune response Neutrophil
- 12. • Bilobed nucleus. • Phagocytic cells • Make up 1% to 6% of all WBC • Fight against multicellular parasitic organism. • Its granules release cytotoxic chemicals that are harmful to parasites. • Aggravates symptoms of allergy and asthma Eosinophil
- 13. • Make up about 1% to 3% of all WBC • Nonphagocytic granulocytes • Large granules that release histamine which is responsible for vessels permeability. • It also release cytokines and other molecules that target antigen that cannot be killed by phagocytosis like worm, helminth, parasite Basophil
- 14. Mast cell • A type of non phagocytic white blood cell • Found in connective tissue especially under the skin, near blood vessels, nerve, intestine, • Contain histamine, cytokines, growth factor • 10 to 15 ng/ml • Target the antigens by degranulation • Respond against parasite, worm, and allergens
- 15. • 2 to 10% • Circulate in the bloodstream as undifferentiated form • They migrate from the blood to the tissue and turn into tissue resident macrophage • two types • Inflammatory monocytes • Patrolling monocyte MONOCYTE Antigen presenting cells
- 16. Macrophage macrophage • Macrophages are specialized cells involved in the detection, phagocytosis and destruction of bacteria and other harmful organisms. • They can also present antigens to T cells and initiate inflammation by releasing molecules (known as cytokines) that activate other cells. Microglial-brain Mesangial- kidney Alveolar-lungs Kupffer cell- liver
- 17. Dendritic Cell • Dendritic cells can develop from both myeloid and lymphoid lineage • bridging innate and adaptive immunity • Detect, capture, engulf, processed of pathogens • Activation of the adaptive immune response by presenting antigenic peptides on major histocompatibility complex (MHC) molecules to induce T cell activation and differentiation
- 18. B Lymphocytes • B Lymphocytes are essential cells of the adaptive immune system. • Developed and mature in bone marrow. • B cells are fewer in number than T cells. • During encounter of antigen B lymphocyte differentiate into Plasma cells and Memory cells. • CD 19 surface marker present on B cell surface • B cell receptor also present on its surface
- 19. T Lymphocyte • Formed in bone marrow and mature in thymus gland • Part of adaptive immune response • Expressed T cell receptor on its surface • Eliminate virus, infected cells, Tumor cells • T cell are differentiate into CD8+ and CD4+ cells • CD8+ T cells, also known as "killer T cells", are cytotoxic – this means that they are able to directly kill virus-infected cells, as well as cancer cells.
- 20. T cell T helper CD4+ T H1 T H17 T H2 T HF T Regulatory T Cytotoxic CD8+ Encounter the Intracellular pathogens Encounter the extra cellular pathogens T regs control the immune response to self and foreign particles and prevent autoimmune disease. Destroy the infected cells, cancer cells
- 21. • NK cells are differentiate and mature in the bone marrow, lymph nodes, spleen, tonsils, and thymus, • It does not require prior activation • NK cells secrete cytokines, Interferon, TNF-α, chemokines, and other factors • Natural killer cells can be found in the skin, uterus, kidney, joints, gut, liver, and breast under normal physiological conditions. • NK cells do not express any receptors on its surface • NK cell play essential role in antibacterial, antiviral, antitumor activities NK CELLS
- 22. Antigen presenting cells • Mediate the cellular immune response ,Acts as a bridge between innate and adaptive immune system • Secretes some proteins during encounter of antigens which attract the other immune cells • phagocytose the pathogens and break them into peptides fragment • APCs present these peptide fragment to other immune cells by MHC class II molecules • Antigen-presenting cells fall into two categories: professional and non- professional. • Those that express MHC class II molecules along with co-stimulatory molecules and pattern recognition receptors are often called professional antigen-presenting cells. • The non-professional APCs express MHC class I molecule
- 23. Professional antigen presenting cells • Macrophage • Dendritic cell • B Lymphocyte Non professional antigen presenting cell • Non-professional antigen presenting cells include all nucleated cell types in the body.
- 24. MHC/ Major histocompatibility complex • Its is very important part of the immune system • Also called HLA (Human leucocytes antigen complex) • MHC are a set of Genes, means its part of our DNA that is encoded by specific proteins • MHC proteins are cell surface proteins required for adaptive immune response to recognize foreign molecules
- 25. FUNCTION Binds with Peptide antigen and display them to T cells MHC class 1 + Antigen T cytotoxic cells (CD8+) MHC class 2 + Antigen T helper cells (CD4+)
- 26. Antigen presentation stimulates immature T cells to become either mature "cytotoxic" CD8+ cells or mature "helper" CD4+ cells.
- 27. Proteins/ Complement proteins • Set of serum proteins that co-operate with both Innate and adaptive immune system to eliminate blood and tissue pathogen. • These are Glycoproteins in nature. • Complete the action of antibody. How to Work • Bind to opsonized pathogen • Make pathogen susceptible for phagocytosis • Create inflammatory response • Eliminate apoptotic cells • Kill pathogen by creating pore in microbial membrane
- 28. Immune system organs and its location s
- 29. Organs of immune system These are two types: Primary and secondary lymphoid organs Primary lymphoid organs • Bone marrow • Thymus Secondary lymphoid organs • Spleen • Lymph node • Tonsils • MALT(mucosa associated lymphoid tissue) Function Development and maturation of immune cells Function Provide action area for encountering of pathogens
- 30. Types of immunity THERE ARE TWO TYPES OF IMMNUNITY: • Innate Immunity • Adaptive immunity • Immunity is the ability of the body to defend itself against disease causing organism, Immunity
- 31. INNATE IMMUNITY • It is non-specific. • It is rapid response appearing within minutes. • Innate immune response is in born and is the first line of defense against pathogen. • It has no memory. • Does not provide long lasting immunity to the host.
- 32. COMPONENTS OF INNATE IMMUNITY Physical barrier: • Skin • Eye • Ear • Mouth • Mucus membrane Chemical barrier: • Cytokines • Defencins • Interferons • Enzymes • Body temperature • PH (stomach PH, vaginal PH) Cellular barrier: • Monocyte • Macrophage • Dendritic Cells • Neutrophils • NK Cells • Eosinophils • Basophils
- 33. Adaptive immunity • Also called Acquired immunity response • It takes long time for activation (5 to 6 hours) • Antigenic specificity • It have immunological memory • Its gives quite strong response • Mediated by T and B lymphocytes
- 34. Types of Adaptive/acquired immunity Types of Adaptive immunity Cellular immunity mediated by mainly T and B lymphocyte Humoral immunity mediated by Antibodies
- 35. Component of adaptive immunity • B Lymphocytes • Plasma cells • T Lymphocytes • T helper cells • T cytotoxic cells • T regulatory cells
- 37. Plasma cell The antibodies Antibody There are 5 classes of antibodies or immunoglobulin produced by plasma cells • IgG • IgA • IgM • IgD • IgE Function Bind to corresponding antigen, and eliminate them. Activate compliment proteins Mediate allergic reaction
- 38. Memory B cell Memory cells Memory helper T cell Subset of B and T lymphocytes differentiates into memory cells which give long lasting immunity to the host against specific antigens.
- 39. Immune Receptors • It is a specialized structures found in the cell membrane. • They are mainly composed of proteins, which bind to pathogens and causes a response in immune system
- 40. Types of immune cells surface receptor Five main type of surface receptor • Antigen receptor • Co- stimulatory receptor • Inhibitory receptor • Cytokines receptor • Chemokines receptor
- 41. Antigen receptor • Immune cells can detect infectious agents and damage cells using receptor • Two main types of Antigen Receptors:- a) Pattern Recognition Receptors PRR are able to recognize pathogen associated molecular pattern. PAMP and DAMP etc. Types of PRR • Toll-like receptor • NOD like receptor • C- type lectin receptor (CLR) • R1G like receptor (RLR) b) Antigen specific lymphocyte receptor: • B- cell receptor • T- cell receptor
- 42. CD80, CD86, CD40 Co- stimulatory Receptor Inhibitory receptor; • Inhibitory receptor are important for regulating natural killer cell activity. • This prevents the NK cells from killing healthy cell. Cytokines receptor Chemokines receptor