Veterinary Immunology Series 1 Sep 16, 2025 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 difference 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 profile and be able to interpret result  Immune System Overview thing you foreign ↑ every protect ftrom organism 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 Inflammation Complement system Antimicrobial substances Fast & nonspecific response Takes time, with specific target No memory : everytime something affected by you are it Generate memory reacts as if it hasn't before. happened S  * Cells of The Immune System Innate Immunity Adaptive Immunity Neutrophil(Natural Immunity) (Acquired B lymphocyte (B cell)Immunity) Macrophage Mast cell & T lymphocyte (T cell) key players in immunity Eosinophil Basophil Natural killer cells Dendritic Cells  Phagocytes Granylocytes ↑ that : eat anything comes in shoot out granyl to kill. Contact with them. 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  able to eat invading : bacteria. 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 bacteria : ingest that enters. · bacteria never comes in contact with the cytoplasm  Invader Defense System Alarm Activation ➡ Siren ➡ Reinforcement Phagocyte Activation ➡ Cytokine ➡ Reinforcement breleased by phagocyte.  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 (not that many bacteria so it is able · : too much bactric , not able to be eliminated) Pathogen Pathogen. to eliminate. 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 Bi T cells that are brought RBC in 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. : surface greater Grea : cell with extensions. Activated Dendritic Cell Dendritic Cell  Antigen Receptor B cell Receptor Y T cell Receptor T-cell : makes antibodies. · receptors will stay on. antigen ↳ receptor. after vaccines · antibodies are made from bells. Y Y T Y Y Y B Y Y Y B lymphocyte Antibody T lymphocyte  Lymphocyte activation (Over-simplified Version) : activated. Plasma cell Y · able to Identify Y antigen- Y B Y Y Y Y B Y + Y Y Y Y Y Y Y T ↓ see what they Activated Dendritic Cell like T : before activation. : activated Naive Lymphocytes Cytotoxic T cell  Activation of Humoral Immunity Tetanus needle misplacement Skin barrier breached Tetanus clearance Phagocytosis by immune cells (Small quantity) - too much Dendritic Cell Activation bacteria. Antigen Presentation Y B cell receptor recognition cell and make antibodies Y. B plasma Y. becomes Y Y B Lymphocyte Activation YY Y Y Antibody Production Produce Neutralizing Antibody Y (Plasma cell) Y  : remains outside the cell- : remains Bacteria (Extracellular Pathogen) in GI tract.  Bacterial Infection (Extracellular Pathogen) Adaptive Immune Response Humoral Immunity ↓ from the bone marrow. Antibody Production (Neutralization of Bacteria)  Virus (Intracellular Pathogen) Self-protein Viral protein Class I MHC Class II MHC ↓ : found in all cells replace found in cells , · mostly immune. cells in the body infection. have an Only there when you ·. cells not always telling · the eat them. 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 · B cell Interacts with deadrite and identify foriegns. and becomes active. 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) - T-cell will kill the foreigns directly. 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) : cell mediate. with Band T cells. Adaptive Immune Response Cell-mediated Immunity Cytotoxic T cells (Target Virally-infected Cells) Self vs Non-self Protein (3D structure of amino acids) linear chain.  Self vs Non-self (Basis of Antigen Receptor Activation) attack) Identical. (not an antigen , will not. - W Self-protein Self or non-self?  Self vs Non-self (Basis of Antigen Receptor Activation) Different and will attack. - Epitope (Antigentic). * W Self-protein Self or non-self?  Self vs Non-self (Basis of Antigen Receptor Activation) of Self-protein Self or non-self?  Self vs Non-self (Basis of Antigen Receptor Activation) # Sside chain different - Epitope lantigen). 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% Confidence Interval) 95 % will 100 sample · in this range · be. 5% are healthy- Haematology Reference Range (95% Confidence Interval) Patient infected of neutrophils 33.0 has been a lot body. ,  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% Confidence Interval) Patient some breeds that have a high blood cell shepard 20.0 count : german · alasken malamute. charts- · callerking 14.0 Haematology Reference Range (95% Confidence Interval) Patient (bone marrow has too much of bone 30.0 marrow) high. Leukemia evidence. 2.5 low  * quiz! Key Terms to know/understand evident eicetme ent nota roblems - - r7 » Innate vs adaptive immunity P » Phagocyte and phagocytosis » Antigen » Epitope » Antigen presenting cells » Humoral Immunity » Antibody » Cell-mediate Immunity » MHC molecules (Class I and Class II)