Vaccination and Tolerance - 2.3 PDF

**[Vaccination and tolerance - 2.3 ]** Tolerance = 1. 2. 3. T and B cell tolerance - - - Non reaction to foreign AG Barries = compartmentalisation T reg cells maintain homeostasis T regs produce immunosupressibe cytokines - IL-10, TGF-B, IL-35  Immunologica...

**[Vaccination and tolerance - 2.3 ]** Tolerance = 1. 2. 3. T and B cell tolerance - - - Non reaction to foreign AG Barries = compartmentalisation T reg cells maintain homeostasis T regs produce immunosupressibe cytokines - IL-10, TGF-B, IL-35  Immunological tolerance - - - Acquired immunity 1. Eg: tetanus, HBsGg, rabies 2.  **Poliomyelitis** 3 strains of Polio virus = faeco-oral transmission 95% of infections are mild 0.5% invades motor neurones via gut → irreversible paralysis Types of polio vaccine: 1. - - - 2. - - - - - **Vaccines** Aim = reproduce natural infection without causing wild-type disease Subunit vaccines - - Toxoid vaccines - - - - Conjugate vaccines - - - - Inactivated whole vaccines - - - - Live attenuated vaccines - - - - Problems with subunit/killed vaccines - - - - Boosters - - - - Problems with live vaccines - - -  Pfizer and Moderna: mRNA Oxford/AstraZeneca: viral vector  Dangers associated with vaccines **Vaccines for oral diseases** Caries (streptococcus mutans) - - Perio disease - - HPV - - - - - HPV and cervical cancer - - - -  HPV and oropharyngeal cancer - - - HPV vaccine - Gardasil - - - - Issues: - **UK immunisation schedule** **Major diseases with no vaccine** - - **Disease** **Problems** ---------- ----------------------------- ------------------------------------------------------------------------ Viruses HIV Antigenic variation; immunosuppression? Herpes Virus Risk of reactivation (varicella-zoster appears safe) Adenoviruses, Rhinoviruses Multiple serotypes Respiratory Syncytial Virus Generation of neutralising antibodies; failure of killed virus vaccine Hepatitis C Antigenic variation; difficult to grow in vitro Dengue Multiple serotype; poor animal models SARS Need for robust T cell response in addition to antibody West Nile Virus Equine vaccine but has caused severe reactions Bacteria Staphylococci Early vaccines ineffective (antibiotics originally better). Group A Streptococci Early vaccines ineffective (antibiotics originally better). Mycobacterium Lepra (BCG gives some protection) Treponema pallidum Ignorance of effective immunity Chlamydia spp. Early vaccines ineffective Fungi Candida spp. Ignorance of effective immunity Pneumocystis spp. Ignorance of effective immunity Protozoa Malaria Antigenic variation Trypanosomiasis Extreme antigenic variation; immunopathology; autoimmunity Leishmaniasis Variable effectiveness of vaccines in humans Worms Schistosomiasis (Trials in animals encouraging) Onchocerciasis Ignorance of effective immunity **Advances in vaccine technology** DNA vaccines  Tumour vaccines