Unit 1361: Fundamentals of Immunology

1. Introduction to Immunology

1.1 Overview of the Immune System

• Components: Organs, cells, and molecules
• Functions: Defense against pathogens, surveillance, and homeostasis

1.2 Innate Immunity

• Physical and chemical barriers
• Cellular components: macrophages, neutrophils, dendritic cells, natural killer cells
• Mechanisms: phagocytosis, inflammation, complement system

1.3 Adaptive Immunity

• Characteristics: specificity, memory
• Cells involved: B lymphocytes, T lymphocytes
• Primary and secondary immune responses

2. Antigens and Antibodies

2.1 Antigens

• Definition and properties
• Types: exogenous, endogenous, autoantigens
• Epitopes and antigenic determinants

2.2 Antibodies (Immunoglobulins)

• Structure: variable and constant regions, Fab and Fc fragments
• Functions: neutralization, opsonization, complement activation

2.3 Antigen-Antibody Interactions

• Affinity and avidity
• Types of antigen-antibody reactions: precipitation, agglutination, complement fixation

3. Immunoglobulins (Ig)

3.1 Classes of Immunoglobulins

• IgG, IgA, IgM, IgE, IgD

3.2 Functions of Each Class

• IgG: main antibody in blood, crosses placenta
• IgA: mucosal immunity
• IgM: primary immune response
• IgE: allergy and parasitic defense
• IgD: B cell receptor

3.3 Role in Humoral Immune Response

• Antibody production and secretion
• Class switching and affinity maturation

4. Major Histocompatibility Complex (MHC)

4.1 Structure and Classes

• MHC Class I and Class II molecules

4.2 Antigen Presentation

• MHC I presentation to CD8+ T cells
• MHC II presentation to CD4+ T cells

4.3 Role in T Cell Activation

• Co-stimulatory signals
• T cell receptor recognition

4.4 Significance in Transplant Immunology

• Tissue compatibility
• Graft rejection mechanisms

5. Cell-Mediated Immunity

5.1 T Cell Subsets

• Helper T cells (Th1, Th2, Th17)
• Cytotoxic T lymphocytes (CTLs)
• Regulatory T cells

5.2 Natural Killer (NK) Cells

• Mechanisms of target cell killing
• Role in innate immunity

5.3 Defense Against Intracellular Pathogens

• Viral infections
• Intracellular bacteria and protozoa

6. Humoral Immunity

6.1 B Cell Activation

• Antigen recognition and processing
• T cell dependent and independent activation

6.2 Antibody Production

• Plasma cell differentiation
• Secretion of antibodies

6.3 Memory B Cells

• Formation and role in long-term immunity
• Secondary immune response

7. Hypersensitivity Reactions

7.1 Type I (Immediate) Hypersensitivity

• Mechanism: IgE mediated
• Examples: allergies, anaphylaxis

7.2 Type II (Cytotoxic) Hypersensitivity

• Mechanism: antibody-mediated cell destruction
• Examples: hemolytic anemia, Goodpasture’s syndrome

7.3 Type III (Immune Complex) Hypersensitivity

• Mechanism: immune complex deposition
• Examples: serum sickness, systemic lupus erythematosus

7.4 Type IV (Delayed) Hypersensitivity

• Mechanism: T cell mediated
• Examples: contact dermatitis, tuberculosis skin test

8. Autoimmune Diseases

8.1 Causes and Mechanisms

• Genetic and environmental factors
• Loss of self-tolerance

8.2 Common Autoimmune Disorders

• Rheumatoid arthritis
• Type 1 diabetes mellitus
• Multiple sclerosis

8.3 Role of Autoantibodies

• Pathogenic effects
• Diagnostic markers

9. Immunodeficiencies

9.1 Primary Immunodeficiencies

• Genetic causes
• Examples: Severe Combined Immunodeficiency (SCID), DiGeorge syndrome

9.2 Secondary Immunodeficiencies

• Causes: infections (HIV), malnutrition, chemotherapy

9.3 Clinical Manifestations

• Increased susceptibility to infections
• Opportunistic infections

10. Serological Testing

10.1 Principles of Serological Tests

• Detection of antibodies and antigens
• Sensitivity and specificity

10.2 Common Serological Techniques

• Enzyme-Linked Immunosorbent Assay (ELISA)
• Western Blot
• Agglutination Tests

10.3 Applications

• Diagnosis of infectious diseases
• Monitoring immune response and vaccination
• Autoimmune disease detection