Cellular and biochemical mediators of immune response By - (M-PHARM SEM-ii) Dept. of-PHARMACOLOGY

Immune system is a collection of organs, special cells and substances that help protect you from infections and some other diseases The specific reactivity induced in a host by an antigenic stimulus is known as immune response Protection against invading MCO It may lead to consequence which may be either beneficial, indifferent or injurious The immune response can be of 2 types – Humoral mediated immunity (HMI) – Cell mediated immunity (CMI) 4/3/ :14 PM2

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1. B cells Develop from stem cells in the bone marrow. Produce antibodies with specificity for antigens and display it on their surfaces to function as BCRs. Integral in humoral immunity Plasma cells = terminally differentiated B cells that secrete immunoglobulins. Memory cells- secondary immune response is swifter and stronge Upon activation, a B cell can switch to produce a different class of antibody, with the same antigen specificity. Activation into antibody secreting cells is antigendependent. 4/3/ :14 PM5

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T cells T lymphocytes develop in the thymus. Regulate immune responses. Integral in cell mediated immunity. Critical in B cell-antibody production Mature T cells display either CD4 or CD8 Cells with a CD4 marker are called helper T cells (Th cells). CD8 marker positive cells are cytotoxic T cells (Tc cells). There are several different types of T cell, and they have a variety of functions : 4/3/ :14 PM7

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Natural killer cell  NK cells are located predominantly in the blood, lymphoid organs, liver and lung.  NK cells are activated in response to interferons or macrophage-derived cytokines.  NK exert their cytolytic effects using perforin and granzymes  Upon release in close proximity to a cell slated for killing, perforin forms pores in the cell membrane of the target cell through which the granzymes and associated molecules can enter, inducing apoptosis. 4/3/ :14 PM9

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neutrophill 4/3/ :14 PM11

Eosinophil 4/3/ :14 PM12

Basophil 4/3/ :14 PM13

Mast cell 4/3/ :14 PM14

Macrophage Macrophage are tissue resident tissue professional phagocytes and antigen presenting cell They differentiate from circulating peripheral blood monocyte They are normally found in the liver, spleen, and connective tissues of the body. 4/3/ :14 PM15

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Dendritic cell Dendritic cell (DCs) are component of innate immune system Their main function is to process antigen material and present it on the surface to T- cell thus functioning as antigen presenting cell 4/3/ :14 PM17

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