1 / 13

Hypersensitivity Reactions type IV

Hypersensitivity Reactions type IV. PhD. student kefah F.Hasson 2014. Characteristics Interaction of primed T cells and associated antigen Involve reactions by T memory cells. Reactions are delayed by one or more days (delayed type hypersensitivity -DTH) .

zea
Download Presentation

Hypersensitivity Reactions type IV

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Hypersensitivity Reactions type IV PhD. student kefahF.Hasson 2014

  2. Characteristics • Interaction of primed T cells and associated antigen • Involve reactions by T memory cells. • Reactions are delayedby one or more days (delayed type hypersensitivity -DTH) . • Infiltration of Mononuclear Cells ( Inflammatory response).

  3. Delayed is relative because DTH response arise 24-72 hours after exposure rather than within minutes. • Delay is due to migration of macrophages and T cells to site of foreign antigens. • Reactions are frequently displayed on the skin: itching, reddness, swelling, pain

  4. Mechanism of type IV hypersensitivity • Inflammation and tissue injury mediated • by CD4+Th1. • Immune injury mainly caused by infiltration of mononuclear cells and lymphocytes , release cytokines . • 2) Cytotoxicityof CD8+CTL

  5. BACTERIA M.tuberculosis Brucella abortus Listeria monocytogen • Virus Measles Herpes simplex • Fungus Histoplasma Candida • protozoa Leishmania • Others Ivy poison Hairs dye Metals poison Nickel salts INTRACELLULAR PATHOGENS INDUCE DELAYED TYPE

  6. Effector phase

  7. Diseases of Type IV (Cell-Mediated) : • Infectious delayed type hypersensitivity like : OT( Old Tuberculin ) test. • 2) Contact dermatitis :like water blister . • 3) Acute rejection of allogenic • transplantation .

  8. Allergic Contact Dermatitis Response to Poison Ivy

  9. Granuloma Formation from DTH Mediated by Chronic Inflammation

  10. THANK YOU

  11. Four types of Hypersensitivity Reactions Type II Type I Ag Target cell Y Y Y Y IgG IgE Target cell Fc receptor Fc recep- tor Killer cell Y Mast cells Ab Histamine Complement Type III Type IV Ag Ag Y Complement Y Th Th cell Endothelial cells Ab Macrophage Y Y Cytokines Neutrophils Activated Macrophage

  12. Topic for exam • The Gall & Coombs classification of hypersensivity reactions . • Type I ,II ,III ,IV hypersensivity reactions mechanism & example . • Immunological basis of the HDN caused by Rh incompatibility . • Mention the common diseases of each types of hypersensivity reactions.

More Related