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qqqqqqqqqqq - exam.step1 - ArchivalUser - 01-21-2014
A 27 yrs old student is coughed on by a patient who suffers from active pulmonary TB, and she never been exposed to TB before. Which one would likely happen in first week.
A. Intracellular proliferation
B. Epitheloid transformation of monocyte
C. Scattered area of caseous necrosis
D. Interfron secretion by active T lymphocyte
E. mounting response by B lymphocyte
0 - ArchivalUser - 01-21-2014
A.
0 - ArchivalUser - 01-21-2014
that's reason i should not ans
0 - ArchivalUser - 01-21-2014
d
0 - ArchivalUser - 01-21-2014
a
0 - ArchivalUser - 01-21-2014
delayed hypersensitivity takes.. 3- 4 weeks to get established, by t lymphocytes. till then bacteria proliferate in macrophages,
0 - ArchivalUser - 01-21-2014
a
thank you.
0 - ArchivalUser - 01-22-2014
AAAAA
0 - ArchivalUser - 01-22-2014
please post correct answer when you get a chance, thnks so much
0 - ArchivalUser - 01-22-2014
Sorry for delay!
AA is right!
large droplet of TB goes to trachea and bronchial epithelium and remove by mucocilliary motion, smaller droplet carried to alveoli can establish infection. most droplet of infectious size can carry 5 organism pul tuberclosis infection established after gravity assisted of small , organism -laden droplet into lower lung filed. macrophage phagocytozed them and sulfatide virulence factor expressed by m. TB allowa for prolifereation inside macrophage proliferation kills macrophage and celluar lysis happen. which phgaocytozed by another macrophages. Virulance factors by M. TB promoterecruitment virulance factor recruits more macrophage and undermine immunologic intracellular signalling between APC and T helepr cell. finally antigen carrying macrophage or dendritis cells migrate to lymph nodes and iduce T cell response it happen 2-4 weeks following initial infection. scattered necrosis: T h and macrophage release cytokine and attract other lkymphocyte and leads to tissue necrosis and collection of macrophage , giant cells and lymphocyte and collagen secreting fibroblast whcih leads to caseating granoloma. small foci bacterai desytryued but larger one wall off and
calcified and make ghon foci a potential for reactivation.
Mounting B cell is when APC meet Th and it releases IFN gamma activates macrophage and Th 2 activated release IL 4 which activated B cells.
B lymphocyte undergoes class switching from IgM to IgGand other subsets. this is happen 2-4 weeks aftare exposure.
IFN gamma release from Th activated macrophages and allows them become epitheloid cells and improve theri ability to kill intracellular TB, it happen
2-4 weeks afetr initial infection which organism is ingested by macrophages and presented to Th lymphocyte.