Veterinary Immunology II Sep 18, 2024.pdf

Veterinary Immunology Series II Allergy Vaccine Herd Immunity Learning Objectives Understand the mechanism of allergic reaction Clinical application of allergy medicine Vaccination: primary shot and booster Understand the concept of herd immunity ...

Veterinary Immunology Series II Allergy Vaccine Herd Immunity Learning Objectives Understand the mechanism of allergic reaction Clinical application of allergy medicine Vaccination: primary shot and booster Understand the concept of herd immunity  Allergy (National Institutes of Health definition) An exaggerated response from the body’s immune system to otherwise inert substances present in the environment 4 Major Allergic Skin Conditions Affecting Dogs and Cats Contact dermatitis / Contact Allergy Flea Allergy / Flea Bite Hypersensitivity Food Allergy Atopic Dermatitis  Atopic Dermatitis (AD) Complex, multifactorial condition It is a clinical syndrome Not a single disease Most common cause of itching in dogs Diagnosis: Exclusion of other What Causes The “Itch” in Allergy? Histamine  Phagocytes Granylocytes In Tissue Macrophages Natural killer cells (Skin, organs) Dendritic Cells Mast cells Neutrophils Neutrophils In Blood Macrophages Eosinophils (Circulation) Dendritic Cells Basophils Canine Mast Cell Equine Mast Cell What triggers the mast cell to release their granules (degranulation)?  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  B Lymphocytes & Antibodies Y Y B Y Y Y Y Y Y B Y B Y Y Y Light chain Y Heavy chain Y B Constant Fragment (Fc) Y Y Y Y 5 di erent classes all recognize the same antigen? Y B Y Y B Y Y Y Naive B cells (B cell receptor repertoire) ff  Naive B cells “sampling” antigen presenting cell Y Y B Y Y Class I MHC Y Y Y Y B Class II MHC Y B Y Y Y Y Non-self Y B Y Y Y Self Y Y B Y Y B Y Y Y Naive B cells (IgM or IgD only) Naive B cell activation by antigen presenting cell Y B cell receptor Class I MHC IgM or IgD Y B Y Y Class II MHC Non-self Self B cell activation and clonal expansion Y Y Y Y Y B Y Y Y B Y Y Y B B Y Y Y Y Y Y Y Y B Y Y Y Y B Y Y Y B Y Y Y B Y Y Y Y Y Y B Y Y Y B Y Y Y B Y Y Y Y Y Y Y Y Y B B B Y Y Y Y Y Y B cell activation followed by antibody class switching  B cell activation followed by antibody class switching One cell = One choice “Only Switch Once” Cytokines (Signalling molecules) Antibody Class & Function https://ruo.mbl.co.jp/bio/e/support/method/antibody-isotype.html https://www.biorender.com/template/ige-operates-through-the-fc-receptor-fceri-on-mast-cells  Allergy Priming and Reaction Exposure to an Antigen B cell produce IgE Phagocytosis by immune cells IgE - binds to mast cell IgE Dendritic Cell Activation receptor Antigen Presentation Re-exposure to antigen B cell receptor recognition IgE receptor Crosslinking B Lymphocyte Activation Mast cell degranulation B cell clonal expansion Histamine release Antibody Class Switching Itch (or Anaphylaxis!) Vaccine  Decision making time A breeder wants to sell their 4 weeks old puppies - should you vaccinate them? A person brought a stray puppy to the clinic and he wants to keep the puppy, the puppy eyes aren’t open, should you vaccinate the puppy? A wealthy client adopted a 3 months old puppy with unknown medical history for a health check, they don’t plan to take the dog outside of their 4-acre property, should you recommend vaccination?  Mate rnal I mmu nity Ab level Minimum Ab level need for protection Ab level c t io n Minimum Ab level need for protection p rod u t i body u r al An Nat 0 week 2 week 4 week 6 week 8 week 10 week 12 week  Vaccinate @ 6 weeks Mate rnal I mmu nity Ab level Minimum Ab level need for protection Ab level c t io n Minimum Ab level need for protection p rod u t i body u r al An Nat 0 week 2 week 4 week 6 week 8 week 10 week 12 week Why Booster? B cell activation and clonal expansion Y Y Y Y Y B Y Y Y B Y Y Y B B Y Y Y Y Y Y Y Y B Y Y Y Y B Y Y Y B Y Y Y B Y Y Y Y Y Y B Y Y Y B Y Y Y B Y Y Y Y Y Y Y Y Y B B B Y Y Y Y Y Y  B cell activation followed by antibody class switching One cell = One choice “Only Switch Once” B cell activation followed by antibody class switching Small number of activated B cell will become plasma cell Plasma cell = Antibody Secreting Memory Cell Naive B cell vs Antibody Secreting Memory Cell Activation Speed Slow Fast Class switching Yes No Clonal Expansion Yes Yes Life span Short (weeks to months) Long (years) Self-renewal / division No Yes Antigen Biding Strong Very Strong Antibody production Medium High https://teachmephysiology.com/immune-system/adaptive-immune-system/immune-memory/ Do we need to provide annual vaccination? If not, why not? If so, how often? Immunology Applications  Bedinvetmab (mab = monoclonal antibodies) Y Y Y B Y Y B Y Y YY YYYY Y Y Y Y Y Y Y B Y Y Y Y Y Y Y Y Y B Y Y B Y Y Y Polyclonal Antibodies Monoclonal Antibodies (Mix population of activated naive B cell) Cloned population Mixture of antibodies bind to the same antigen All antibodies bind to the same epitope Nerve Growth Factor Pain Response Nerve Growth Factor  Cytopoint = Lokivetmab (Anti-interleukin 31 antibody) Clostridium tetani is found in soil and intestinal tracts. In most cases, it is introduced into the body through wounds, particularly deep puncture wounds. Sometimes the point of entry cannot be found because the wound itself my be minor or healed. The bacteria remain the dead tissue at the original site of infection and multiply. As bacterial cells die and disintegrate, the potent nerve toxin is released. The toxin spreads and causes spasms of the voluntary muscles Herd Immunity West Nile virus Does Herd Immunity matter to Vaccinated against WNV Unvaccinated Eastern Equine Encephalitis Virus Does Herd Immunity matter to Vaccinated against EEE Unvaccinated Does Herd Immunity matter to Vaccinated against EEE Unvaccinated