the Hypersensitivity types with detail .pptx

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1. Define and explain “ HYPERSENSITIVITY ” Defination : “It is a state of increase sensitivity to an antigen arising from the previous exposure to that antigen “. The state of abnormal physiological condition in which there is undesireable or adverse immune response to a harmless antigen is called H YPERSENSITIVITY. Types: Hypersensitivity has been classified by Gell and Combs in four Classes: Anaphylactic hypersensitivity. Cytotoxic Hypersensitivity. Complex mediated Hypersensitivity. Cell mediated Hypersensitivity.

2. i . TYPE-I Anaphylactic hypersensitivity: Mediated by IgE type of antibodies in response to specific antigen called Allergen. This reaction may be life threatening accompanied by Anaphylaxis in which the mediators induce severe contraction of body’ smooth muscle . e.g Common allergens (pollens , drugs like pencillin ) ii. Type-II Cytotoxic Hypersensitivity: This reaction occurs when a specific antibody ( i.e IgG or IgM ) causes destruction of Host cells. e.g Blood transfusion reaction, Erthroblastosis fatalis ( Hemolytic reaction in new born)

3. Type –III Immune complex Hypersensitivity: Caused by deposition of immune complex ( antigen + antibody ) at various body locations i.e blood vessels , kidneys, joints, lungs and skin etc. e.g serum sickness , Rhematoid arthritis. Type- IV Cell mediated Hypersensitivity: It is an exaggeration of T- lymphocytes and develops beginning 18-24 hours following contact with antigen and peaks 2-3 days . e.g infection allergy , contact dermatalis .

4. Classes of Hypersensitivity:

5. Major classes of Antibiotics: Broad spectrum Narrow spectrum Effective against a wide range of bacteria: Broad spectrum agents can target both Gram +& Gram - types of bacteria and as well as other types of bacteria More likely to target normal flora. Broad spectrum agents can distrupt the balance of normal flora in the body leading to potential side effects such as Diarrhea. . Increased risk of resistance: The overuse of broad spectrum agents contribute to Antibiotic- Resistance Effective against specific types of bacteria : Narrow spectrum agents can target a specific type bacteria or microbes. Less likely to contribute antibiotic – Resistance : Narrow spectrum agents are less likely to contribute to the development of antibiotic -resistance against bacteria as they target specific microbes. Fewer side –effects ; Narrow spectrum agents tend to have fewer side effects as they less likely to distrupt normal flora.

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