The Physiology Of Immunity

THE PHYSIOLOGY OF IMMUNITY _______________________ Delfin Arnel D. Razon, MD., DPBA Department of Medical Physiology Pamantasan ng Lungsod ng Maynila College of Medicine

Cells Mediating the Immune Response: Leukocytes granulocytes monocytes lymphocytes B cells T cells cytotoxic T cells helper T cells suppressor T cells NK cells Plasma cells Macrophages Mast cells

IMMUNE SYSTEM

Innate immunity

Acquired immunity

defences at body surfaces phagocytosis inflammation complement activation

Humoral Immunity Cellular Immunity

PHAGOCYTOSIS • 3 Important Cells 1. Neutrophils Circulating pool Marginated pool .respiratory burst .signal transduction/stimulus response coupling 2. Circulating monocytes 3. Fixed tissue macrophages

ACUIRED IMMUNITY (ADAPTIVE IMMUNITY) • LYMPHOCYTES • T-cells • B-cells .plasma cells IgG IgD IgA IgE IgM . NK cells • RECEPTORS • recognition

HUMAN T cell

Human Immunoglobulins Antibody IgA

IgD IgE

IgG IgM

Location Gut, respiratory tract and urogenital tract mucosa

- complement fixation majority of Ab based immunity Surfaces of Bcells/secreted form

Function -prevents colonization of pathogens -localized protection in external secretions Antigen receptor on B cells -binds to allergens and triggers histamine release -involved in allergy protection vs parasitic worms - complement fixation - majority of Ab based immunity - Complement fixation - Pathogen elimination in early stages of B cells response

T cell response ANTIGEN PRESENTATION • APCs • MHCs MHC class I- all nucleated cells of the body MHC class II- macrophages, macrophage-like cells, B cells • MHC restrictions Helper T cells = MHC class II restricted Cytotoxic Tcells = MHC class I restricted

NK cells physiologic role

CLONAL DELETION And CLONAL INACTIVATION

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