3E_Allergic Immune Response

Page 1: Introduction to Immunoengineering

  • Topic: Immunoengineering

    • Focus on Allergy and Autoimmunity

    • Associated with Johns Hopkins Whiting School of Engineering

Page 2: Mechanisms for Allergic Reactions

  • Types of Allergic Reactions:

    • Type I: Mediated by IgE (e.g., allergic rhinitis, asthma, anaphylaxis)

    • Type II: Involves IgG antibodies (e.g., penicillin allergies)

    • Type III: Associated with immune complexes (e.g., serum sickness, Arthus reaction)

    • Type IV: Delayed-type hypersensitivity (e.g., allergic contact dermatitis)

  • Immune Reactants:

    • Type I: IgE

    • Type II & III: IgG

  • Effector Mechanisms:

    • Type I: Mast-cell activation

    • Type II: Complement activation

  • Examples of Hypersensitivity Reactions:

    • Type I: Allergic asthma, eczema, anaphylaxis

    • Type II: Serum sickness

    • Type III: Allergic contact dermatitis

Page 3: Mast Cell Activation

  • Mast Cells:

    • Derived from bone marrow

    • Migrate to tissues

    • Contain electron-dense secretory granules

Page 4: Mast Cell Secretory Granules

  • Components:

    • Lysosomal Enzymes: Cathepsin, β-hexosaminidase

    • Biogenic Amines: Histamine, Serotonin, Dopamine

    • Cytokines: TNF, IL-4, IL-6

    • Growth Factors: bFGF, VEGF

    • Proteoglycans: Serglycin

    • Proteases: Tryptase, Chymase

    • Antimicrobial peptides and Heparanase

Page 5: Mast Cell Granules - Proinflammatory

  • Pro-inflammatory Role: Release of mediators that lead to inflammation

Page 6: Protective Mast Cell Function

  • Function: Involved in protective immune responses against pathogens

Page 7: Detrimental Mast Cell Function

  • Impact: Can lead to allergic diseases when activated excessively

Page 9: Mast Cell Activation and Symptoms

  • Type I Reaction: Activation leading to allergic symptoms

    • Gastrointestinal Tract: Increased fluid secretion, peristalsis

    • Nasal Passages: Decreased diameter, increased mucus

    • Blood Vessels: Increased permeability causing potential anaphylactic shock

Page 10: Food Allergy Example

  • Allergen Effects:

    • IgE-mediated activation of mast cells causing vasodilation and increased permeability

    • Symptoms: Vomiting, diarrhea, urticaria, respiratory distress

Page 11: Development of IgE Antibodies

  • Process:

    • Dendritic cells present antigens to T cells

    • T cells stimulate B cells for IgE production

    • IgE binds to mast cells, leading to degranulation and allergic symptoms

Page 12: Positive-feedback Reaction

  • Mechanism: Activated mast cells signal B cells, increasing IgE production

Page 13: Sources of Th2 Cells

  • TH1/TH2 Balance: Sources and functions in immune response

Page 14: Th2 T Cell Development

  • Research: Characteristics and origin of Th2 cells in immune response

Page 15-17: Th1 vs. Th2 Induction

  • Induction Factors: Antigen-presenting cells and their role in T cell differentiation

Page 19: Introduction to Basophils

  • Role: Involvement in autoimmune and inflammatory diseases

Page 20: Introduction to Eosinophils

  • Function: Role of tissue-resident eosinophils in immune responses

Page 21-23: Detailed Overview of Mechanisms for Allergic Reactions

  • Reiteration of Types I-IV Mechanism: Immunological processes and examples of hypersensitivity

Page 24-28: Entry and Dose Effect

  • Allergen Entry Points: Various routes (IV, subcutaneous, inhalation)

  • Effects: Systemic responses leading to anaphylaxis, localized reactions, chronic symptoms

  • Timing of Reactions: Differentiation between acute and chronic responses due to inflammatory mediators