Type III and IV Hypersensitivity Reactions Flashcards
What occurs with a Type III reaction?
Antigen-Antibody complexes form and deposit to cause tissue damage
What occurs with a Type III reaction?
Antigen-Antibody complexes form and deposit to cause tissue damage
When Antigen-Antibody complexes deposit, what gets released?
Complement fragment causes Histamine release
When Histamine is released near the Antigen-Antibody complex, what does that cause?
Neutrophils arrive and release enzymes
When Neutrophils arrive and release enzymes at the site of the Antigen-Antibody deposit, what does that cause?
TISSUE DAMAGE
Common sites for Antigen-Antibody complex deposition?
Kidney Vessels Joints Skin Heart, lungs
Serum Sickness is a ____ Antigen-Antibody deposition
Skin
Acute form of Serum sickness is due to?
Non-human protein Antigen (diptheria anti-toxin)
Chronic form of Serum sickness is due to?
Self antigen = LUPUS
Lupus is a Type ____ Hypersensitivity reaction
III
An Arthus reaction is a _____ reaction
Local
In what 2 populations were Arthrus reactions seen?
Rabbits injected with horse serum
Rare local effect of vaccination
How do you detect whether a disease is Type II or Type III?
Immunoflourescence biopsy
What do Immunofluorescence biopsies detect?
Pattern of Antibody deposition and thus, the disease process
Describe the process of an Immunofluorescence biopsy
- Anti-Ig Antibodies (antibodies for antibodies) are tagged with fluorescent dye
- Then administered to tissue
= Will bind to any Antibodies present
If an Immunoflourescence biopsy is smooth and linear, what does that indicate?
TYPE II
- Antibodies are DIRECTLY acting on tissue
If an Immunoflourescence biopsy is grainy and granular, what does that indicate?
TYPE III
- Antibody complexes have DEPOSITED at random
Example of a Smooth and linear Immunofluorescence disease
Type II
- Rheumatic Heart
Example of a Grainy and granular Immunofluorescence disease
Type III
- Post-streptococcal Glomerulonephritis
What controls the Type IV reactions?
T cells
What controls the Type IV reactions?
T cells
Actions of CD4+ T cells?
Inflammation and cytokine release
Actions of CD8+ T cells?
Cytotoxic against Ag on surface of a cell
2 examples of Type IV reaction disease?
Type I Diabetes Mellitus
Granulomas
Type 1 DM is a Type ____ reaction
IV
Granulomas are a Type ____ reaction
IV
Granulomas are what type of immune response?
Persistent T cell mediated immune response
Rheumatoid arthritis, multiple sclerosis and inflammatory bowel disease are what type of hypersensitivities?
Type IV
General cascade of Type IV reactions?
Inflammation by T cells (Th1/17)
Cytokine release
Symptoms
Delayed Hypersensitivity reaction Mantoux Test example
Tuberculin Skin Test
Describe the Tuberculin Skin Test for Type IV reactions
- Purified Protein Derivative (tuberculin) injected intradermally
- 48-72 hours later the reaction is assessed
- Sensitized T cells start inflammatory response
= Local swelling/induration occur
== Indicates current or prior Tb infection
What type of T cells cause inflammatory response with the Tb skin test?
Perivascular CD4+ T cells
