Veterinary Immunology Series 1 Sep 16, 2024.pdf

Veterinary Immunology Series 1 Overview of The Immune System Dr. Samuel Cheung, Veterinarian Revolution Animal Veterinary Services Bachelor of Veterinary Medicine & Surgery (University of Edinburgh) PhD Medical Microbiology and Immunology (University of Alberta) MSc Immunology (University of Mani...

Veterinary Immunology Series 1 Overview of The Immune System Dr. Samuel Cheung, Veterinarian Revolution Animal Veterinary Services Bachelor of Veterinary Medicine & Surgery (University of Edinburgh) PhD Medical Microbiology and Immunology (University of Alberta) MSc Immunology (University of Manitoba) BSc Biochemistry (University of Manitoba) Contact: [email protected] Learning Objectives Know the di erence between innate vs adaptive immunity Be familiar with the cells of the immune system and their main functions Know two branches of adaptive immunity Know how the immune system distinguish self from non-self Understand hematology pro le and be able to interpret result ff fi  Immune System Overview Innate Immunity Adaptive Immunity First line of(Natural defenseImmunity) Third line(Acquired of defenseImmunity) Skin Specialized immune cells Mucous membranes Antibodies Normal microbiota Second line of defense Innate immune cells In ammation Complement system Antimicrobial substances Fast & nonspeci c response Takes time, with speci c target No memory Generate memory fl fi fi  Cells of The Immune System Innate Immunity Adaptive Immunity Neutrophil(Natural Immunity) (Acquired B lymphocyte (B cell)Immunity) Macrophage T lymphocyte (T cell) Mast cell Eosinophil Basophil Natural killer cells Dendritic Cells  Phagocytes Granylocytes In Tissue Macrophages Natural killer cells (Skin, organs) Dendritic Cells Mast cells Neutrophils Neutrophils In Blood Macrophages Eosinophils (Circulation) Dendritic Cells Basophils  You were vaccinating a dog with tetanus, but unfortunately you stabbed yourself with the needle (What would happen to your body?)  Normal Immune Cells Distribution RBC RBC Y Y Y Macrophages Y B Y Neutrophil Y Y RBC B B Y Y Y Y Y Neutrophil T T T RBC Lymph node Dendritic Cells RBC RBC Tissue Blood Lymphatic System Endothelial Cells Endothelial Cells  Bacterial Challenge RBC RBC Bacteria Y Y Y Macrophages Y B Y Neutrophil Y Y RBC B B Y Y Y Y Y Neutrophil T T T RBC Lymph node Dendritic Cells RBC RBC Tissue Blood Lymphatic System Endothelial Cells Endothelial Cells  Phagocytes Granylocytes In Tissue Macrophages Natural killer cells (Skin, organs) Dendritic Cells Mast cells Neutrophils Neutrophils In Blood Macrophages Eosinophils (Circulation) Dendritic Cells Basophils  Phagocytosis and Activation of Innate Immunity RBC RBC Y Y Y Macrophages Y B Y Y Y RBC B B Y Y Y Y Y T T T RBC Lymph Dendritic Cells node RBC RBC What is phagocytosis? Endothelial Cells Endothelial Cells Mechanisms of Phagocytosis  Invader Defense System Alarm Activation ➡ Siren ➡ Reinforcement Phagocyte Activation ➡ Cytokine ➡ Reinforcement  Phagocytosis and Cytokine Production RBC RBC Cytokine Y Y Y Macrophages Y B Y Y Y RBC B B Y Y Y Y Y T T T RBC Lymph Dendritic Cells node RBC RBC Endothelial Cells Endothelial Cells  Neutrophils migration into tissue RBC RBC Y Y Y Macrophages Y B Y Y Y RBC B B Y Y Y Y Y T T T RBC Lymph Dendritic Cells node RBC RBC Neutrophil Endothelial Cells Endothelial Cells  2 possible outcomes Pathogen Pathogen Elimination Takes Over Innate Immunity alone or together with adaptive immunity  Pathogen Eliminated By Innate Immune Cells RBC RBC Y Y Y Macrophages Y B Y Y Y RBC B B Y Y Y Y Y T T T RBC Lymph Dendritic Cells node RBC RBC Neutrophil Endothelial Cells Endothelial Cells Pathogen Eliminated - Host Immune System Reset RBC RBC Y Y Y Macrophages Y B Y Neutrophil Y Y RBC B B Y Y Y Y Y Neutrophil T T T RBC Lymph node Dendritic Cells RBC RBC Tissue Blood Lymphatic System Endothelial Cells Endothelial Cells When the numbers of pathogen are overwhelming RBC RBC Y Y Y Y B Y Y Y RBC B B Y Y Y Y Y T T T RBC Lymph “Activated” node Dendritic cell RBC RBC Endothelial Cells Endothelial Cells Activation of Adaptive Immunity  Cells of The Immune System Innate Immunity Adaptive Immunity Neutrophil(Natural Immunity) (Acquired B lymphocyte (B cell)Immunity) Macrophage T lymphocyte (T cell) Mast cell Eosinophil Basophil Natural killer cells Dendritic Cells Dendritic cell migrate into secondary lymphoid organs and presenting bacterial antigen on MHC class II RBC RBC What is antigen? Y Y Y Y B Y Y Y RBC B B Y Y Y Y Y T T T RBC Lymph “Activated” node Dendritic cell RBC RBC Endothelial Cells Endothelial Cells  What binds to an antigen? Antigen National Cancer Institute definition - Any substance that causes the body to make an immune response against that substance. Antigens include toxins, chemicals, bacteria, viruses, or other substances that come from outside the body. Activated Dendritic Cell Dendritic Cell  Antigen Receptor B cell Receptor Y T cell Receptor Y Y T Y Y Y B Y Y Y B lymphocyte Antibody T lymphocyte  Lymphocyte activation (Over-simplified Version) Plasma cell Y Y Y B Y Y Y Y B Y + Y Y Y Y Y Y Y T Activated Dendritic Cell T Naive Lymphocytes Cytotoxic T cell  Activation of Humoral Immunity Tetanus needle misplacement Skin barrier breached Tetanus clearance Phagocytosis by immune cells (Small quantity) Dendritic Cell Activation Antigen Presentation Y B cell receptor recognition Y B Y Y Y B Lymphocyte Activation YY Y Y Antibody Production Produce Neutralizing Antibody Y (Plasma cell) Y Bacteria (Extracellular Pathogen)  Bacterial Infection (Extracellular Pathogen) Adaptive Immune Response Humoral Immunity Antibody Production (Neutralization of Bacteria)  Virus (Intracellular Pathogen) Self-protein Viral protein Class I MHC Class II MHC Nucleus Nucleus Nucleus Normal Host Cell Virally-Infected Host Cell Viral Protein loading onto MHC Class I Self-protein Viral protein Class I MHC Class II MHC Nucleus Nucleus Nucleus Normal Host Cell Virally-Infected Host Cell  Dendritic Cell Recognizes Viral Proteins then present the antigens on both MHC classes Plasma cell Y Y MHC II Y B Y B Y Y Y Y + Y Y Y Y Y Y Y T MHC I T Activated Dendritic Cell Naive Lymphocytes Cytotoxic T cell T cell activation (Cell-mediated Immunity) Naive T cell T T Nucleus Cytotoxic T cell Target cell (Infected) Dendritic Cell  Under Normal Condition Naive T cell T T No activation Dendritic Cell Activation of Cell-mediated Immunity Viral Infection (intracellular) T Naive T cell Dendritic Cell Activation Antigen Presentation T cell receptor recognition T Lymphocyte Activation Generation of Cytotoxic T cells T Cytotoxic T cell  Viral Infection (Intracellular Pathogen) Adaptive Immune Response Cell-mediated Immunity Cytotoxic T cells (Target Virally-infected Cells) Self vs Non-self Protein (3D structure of amino acids)  Self vs Non-self (Basis of Antigen Receptor Activation) Self-protein Self or non-self?  Self vs Non-self (Basis of Antigen Receptor Activation) Self-protein Self or non-self?  Self vs Non-self (Basis of Antigen Receptor Activation) Self-protein Self or non-self?  Self vs Non-self (Basis of Antigen Receptor Activation) Self-protein Self or non-self? Recognition of foreign protein (Antigen) triggers an immune response Let’s do some vet stuff Haematology Reference Range (95% Con dence Interval) fi  Haematology Reference Range (95% Con dence Interval) Patient 33.0 fi  Neutrophils migration into tissue RBC RBC Y Y Y Macrophages Y B Y Y Y RBC B B Y Y Y Y Y T T T RBC Lymph Dendritic Cells node RBC RBC Neutrophil Endothelial Cells Endothelial Cells  Haematology Reference Range (95% Con dence Interval) Patient 20.0 14.0 fi  Haematology Reference Range (95% Con dence Interval) Patient 30.0 2.5 fi  Key Terms to know/understand » Innate vs adaptive immunity » Phagocyte and phagocytosis » Antigen » Epitope » Antigen presenting cells » Humoral Immunity » Antibody » Cell-mediate Immunity » MHC molecules (Class I and Class II)