L10 zatchot

Question 1

1. Bacterial allergens.

Answer 1

-Intracellular bacteria 
1- mycobacterium tuberculosis 
2- mycobacterium leprea
3- bruecella abortus 
4- listeia monocytogens 
— intercellular viruses 
1-Herpes simplex virus 
2-Variola 
3- measles virus

Question 2

2. Skin testing for Type I hypersensitivity assessment.

Answer 2

• Type I hypersensitivity is commonly assessed by skin testing, an inexpensive and relatively safe diagnostic approach that allows screening of a wide range of antigens at once. Small amounts of potential allergens are introduced at specific skin sites the forearm or back , either by intradermal injection or by dropping onto a site of a superficial scratch. Thirty minutes later, the sites are reexamined. Redness and swelling (the result of local mast cell degranulation) indicate an allergic response
• symptoms: occurs after 30 min and the positive control for the response is histamine and negative response is typically just saline

Question 3

3. Skin testing for Type VI hypersensitivity assessment.

Answer 3

The DTH Reaction Can be Detected by a Skin Test Delayed-type hypersensitivity (DTH)

• • reactions often are used to determine if people have been previously exposed to and have responded to an antigen. For example, a DTH reaction to a mycobacterial antigen, PPD (purified protein derivative), is an indicator of a T cell response to the mycobacteria. This is the basis for the PPD skin test, used to detect past or active mycobacterial infection
• symptoms: development of red , slightly swollen , firm lesion at the sight between 48 and 72 hours