Antibiotics Immunity Overview | Answer Key

University:
University of Wolverhampton
Course:
4PY019 | Pharmacy
Academic year:

2024
Views:

211

Pages:

3
Author:

Carisma W.

Antibiotics and Immunology – Detailed Overview 1. Antibiotics Mechanisms of Action 1.1 Tetracycline • Binds 30S ribosomal subunit • Stops tRNA from binding → inhibits protein synthesis 1.2 Macrolides • Binds 50S subunit • Blocks exit tunnel → stops translocation 1.3 Chloramphenicol • Binds 50S subunit • Inhibits peptidyl transferase → stops peptide bond formation 1.4 Cell Wall-Targeting Antibiotics • Beta-lactams, vancomycin, gramicidin A, cephalosporins Beta-lactamases • Enzymes in bacteria that hydrolyze beta-lactam ring → destroy antibiotic Transpeptidase (PBP) • Enzyme cross-linking peptidoglycan → target of beta-lactams Penicillin G • Mimics D-ala → binds transpeptidase → inhibits cross-linking → cell lysis • Cons: acid sensitive, susceptible to beta-lactamases • Progression: Penicillin G → Ampicillin (NH2 group, less acid-sensitive) → Amoxicillin (bulky side chains, beta-lactamase resistant) → Co-amoxiclav (clavulanic acid inhibits beta-lactamases) 1.5 Vancomycin • Binds terminal D-ala → prevents crosslinks → cell wall weakens → lysis 1.6 Gramicidin A • Forms ion channels → ion leakage → bacterial death 1.7 Cephalosporins • Bind PBPs → inhibit cell wall synthesis → cell death 1 1.8 DNA-Targeting Antibiotics • Quinolones (ciprofloxacin, levofloxacin): inhibit DNA gyrase & topoisomerase IV → prevent DNA synthesis • Nitroimidazoles (metronidazole): imidazole radical binds DNA → breaks strands 1.9 Protein Synthesis Inhibitors • Macrolides, tetracycline, chloramphenicol (see above) 2. Immunology Basics 2.1 Vaccination Steps 1. Exposure via injection 2. Presentation to T cells 3. B cell activation 4. Clonal selection & memory B cells expansion 2.2 Antibody Classes • IgG: most common in blood, long-term immunity, type II hypersensitivity • IgM: first responder, type II hypersensitivity • IgA: mucosal antibodies • IgE: allergy, skin/mucosa • IgD: B cell surface, activates B cells 2.3 Immunity Types • Natural passive: via placenta/breast milk • Natural active: via infection → own antibodies/T cells • Artificial passive: administration of antibodies (e.g., Hep B) • Artificial active: vaccination → own immune cells 2.4 Antibody Structure • N-terminal binds antigen • C-terminal binds cells (e.g., IgD binds B cells) 2.5 Mast Cells & Basophils • Release histamine → itching 2.6 Herd Immunity • Requires ~95% population vaccination 2 3. Hypersensitivity • Abnormal immune response Type I • IgE-mediated, fast, allergic reactions (pollen) Type II • IgG/IgM bind cells → destruction Type III • Immune complexes → vessel inflammation, IgG/IgM Type IV • T-cell mediated, delayed (contact dermatitis, celiac disease) 3