Hypersensitivity

The ppt covers-
Definition
Types-
1. IgE- mediated hypersensitivity (type I)
2. Antibody- mediated hypersensitivity (type II)
3. Immune complex- mediated hypersensitivity (type III)
4. Delayed-type hypersensitivity (type IV)

1. Hypersensitivity

2. Definition Types- 1. IgE - mediated hypersensitivity (type I) 2. Antibody- mediated hypersensitivity (type II) 3. Immune complex- mediated hypersensitivity (type III) 4. Delayed-type hypersensitivity (type IV) Synopsis:-

3. Increase immune response is termed as hypersensitivity or allergy. When immune system work fast then it is required. Types- 1. immediate hypersensitivity 2. delayed-type hypersensitivity (DTH) Hypersensitivity response:-

4. Immediate hypersensitivity Delay-type hypersensitivity Its response is very early, with in 12 hours of antigen attacks. Its response in little slow, it takes 24-48 hours. By antigen-antibody complex or by reactive antibody forms. By reactive T H cell, antigen presenting cell present antigen to TH cell

5. 1. IgE mediated (type-I) hypersensitivity 2. Antibody-mediated (type-II) hypersensitivity 3. Immune complex-mediated (type-III) hypersensitivity 4. Delayed-type hypersensitivity (DTH) Classification of hypersensitivity:-

6. IgE - mediated hypersensitivity Most common cell involved in type-I are basophills and mast cells, because IgE receptor present on the surface of basophills and mast cells Antigen act as allergence  generate allergy Ex: asthma Type-I

7. Antibody-mediated hypersensitivity IgG & IgE Compliment protein play important role in type-II Compliment immediated destruction. ADCC (NKC) response because due to the receptor of IgE & complex protein present on the surface of antigen. Ex: auto immune hemolytic cell Erythroblastosis fetalis Type-II

8. Immune complex-mediated hypersensitivity. The reaction of antibody with antigen generates immune complexes. Large amounts of immune complexes can lead to tissue-damaging type III hypersensitivity reactions. Type-III

9. Delayed-type hypersensitivity When some subpopulations of activated TH cells encounter certain types antigens, they secrete cytokines that induce a localized inflammatory reaction. Generally the T cells activated during the sensitization phase are CD4+, primarily of the TH1 subtype. But in a few cases CD8+ cells have also been shown to induce a DTH response. Type-IV

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