Mechanism of Mast Cell degranulation - USMLE Forums
USMLE Forums Logo
USMLE Forums         Your Reliable USMLE Online Community     Members     Posts
Home
USMLE Articles
USMLE News
USMLE Polls
USMLE Books
USMLE Apps
Go Back   USMLE Forums > USMLE Step 1 Forum

USMLE Step 1 Forum USMLE Step 1 Discussion Forum: Let's talk about anything related to USMLE Step 1 exam


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 10-22-2010
Pixie's Avatar
USMLE Forums Addict
 
Steps History: Step 1 Only
Posts: 161
Threads: 29
Thanked 106 Times in 56 Posts
Reputation: 116
Immunology Mechanism of Mast Cell degranulation

A patient's signs and symptoms are mediated by antigen specific IgE antibody attached to high affinity receptors on surface of mast cells. by which of the following mechanisms does mast cell degranulate?

A- antibody receptor dissociation
B- antibody receptor covalent binding
C- receptor internalization
D- receptor aggregation
E- receptor detachment from cell surface

write not only the correct choice and its explanation, also give example's for rest of options.
Reply With Quote Quick reply to this message



  #2  
Old 10-22-2010
Banned
 
Steps History: Not yet
Posts: 7
Threads: 3
Thanked 0 Times in 0 Posts
Reputation: 10
Default

B
the answer present in kaplan book of immuno-
theres a picture shows that !!!
Reply With Quote Quick reply to this message
  #3  
Old 10-23-2010
Pixie's Avatar
USMLE Forums Addict
 
Steps History: Step 1 Only
Posts: 161
Threads: 29
Thanked 106 Times in 56 Posts
Reputation: 116
Smile

Quote:
Originally Posted by lazmo2002 View Post
B
the answer present in kaplan book of immuno-
theres a picture shows that !!!
and that is wrong answer i also marked the same choice.. try harder.
Reply With Quote Quick reply to this message
 
  #4  
Old 10-23-2010
USMLE Forums Guru
 
Steps History: ---
Posts: 487
Threads: 69
Thanked 296 Times in 133 Posts
Reputation: 316
Default

D-receptor aggregation...???

just a guess...
__________________
258(1)/237(1)/CS pass(1)/YOG 2011/221(1)/6 months USCE/ 3 months observership/4 US LOR /Need visa
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Reply With Quote Quick reply to this message
  #5  
Old 10-23-2010
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 150
Threads: 44
Thanked 95 Times in 27 Posts
Reputation: 105
Default

D is the right answer!!!
Reply With Quote Quick reply to this message
  #6  
Old 10-23-2010
podebrad's Avatar
USMLE Forums Addict
 
Steps History: CK+CS
Posts: 138
Threads: 28
Thanked 77 Times in 36 Posts
Reputation: 87
Default

thnx..tht was a good one..
Reply With Quote Quick reply to this message
  #7  
Old 10-23-2010
USMLE Forums Newbie
 
Steps History: Not yet
Posts: 1
Threads: 0
Thanked 1 Time in 1 Post
Reputation: 11
Default

the answer is D

Aggregation of antigens and binding of IgE to the FcεRI on mast cells causes degranulation and the release of mediators from the cells, while basophils cross-linked with IgE release type 2 cytokines like interleukin-4 (IL-4) and interleukin-13 (IL-13) and other inflammatory mediators.
Reply With Quote Quick reply to this message
The above post was thanked by:
Sabio (10-23-2010)
  #8  
Old 10-23-2010
USMLE Forums Newbie
 
Steps History: Not yet
Posts: 1
Threads: 0
Thanked 0 Times in 0 Posts
Reputation: 10
Default

answer iz D
Reply With Quote Quick reply to this message
  #9  
Old 10-23-2010
USMLE Forums Scout
 
Steps History: Not yet
Posts: 24
Threads: 4
Thanked 19 Times in 11 Posts
Reputation: 29
Default

I'm not sure, but I think it's C.
Reply With Quote Quick reply to this message
  #10  
Old 10-24-2010
USMLE Forums Guru
 
Steps History: 1 + CS
Posts: 405
Threads: 55
Thanked 528 Times in 155 Posts
Reputation: 538
Help

Can someone please explain what does "antigen cross-linking with antibody" means? Is it the aggregation of antibodies with antigens?
Reply With Quote Quick reply to this message
  #11  
Old 10-24-2010
USMLE Forums Addict
 
Steps History: 1+CK+CS
Posts: 167
Threads: 8
Thanked 134 Times in 47 Posts
Reputation: 144
Default answer is D (IgEFc receptor aggregation)

Quote:
Originally Posted by faith View Post
A patient's signs and symptoms are mediated by antigen specific IgE antibody attached to high affinity receptors on surface of mast cells. by which of the following mechanisms does mast cell degranulate?

A- antibody receptor dissociation
B- antibody receptor covalent binding
C- receptor internalization
D- receptor aggregation
E- receptor detachment from cell surface

write not only the correct choice and its explanation, also give example's for rest of options.
answer is D (IgEFc receptor aggregation)
Reply With Quote Quick reply to this message
  #12  
Old 10-24-2010
Pixie's Avatar
USMLE Forums Addict
 
Steps History: Step 1 Only
Posts: 161
Threads: 29
Thanked 106 Times in 56 Posts
Reputation: 116
Correct Answer

Quote:
Originally Posted by donofitaly View Post
Can someone please explain what does "antigen cross-linking with antibody" means? Is it the aggregation of antibodies with antigens?
on first exosure IgE is produced as a response to allergen,it is released in serum and it binds to mast cell Fc receptor.
now remember many IgE antibodies are bound to mast cell and while in serum they have short half life but once bound to mast cell it can survive for years.

so next time when exposure occurs ALLERGEN will cross link several IgE molecules on mast cell-this is the step that will lead to mast cell degranulation.
Reply With Quote Quick reply to this message
The above post was thanked by:
donofitaly (10-24-2010)



Reply

Tags
Immunology-, Step-1-Questions

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the USMLE Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Medical School
Choose "---" if you don't want to tell. AMG for US & Canadian medical schools. IMG for all other medical schools.
USMLE Steps History
What steps finished! Example: 1+CK+CS+3 = Passed Step 1, Step 2 CK, Step 2 CS, and Step 3.

Choose "---" if you don't want to tell.

Favorite USMLE Books
What USMLE books you really think are useful. Leave blank if you don't want to tell.
Location
Where you live. Leave blank if you don't want to tell.

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
The Bainbridge Reflex Mechanism rasheed USMLE Step 1 Bits & Pieces 0 10-18-2010 08:39 AM
which type of defense mechanism? step1an USMLE Step 1 Forum 9 08-25-2010 07:20 AM
Fibrates Mechanism of action? LionofJudo USMLE Step 1 Forum 5 07-23-2010 06:22 PM
Ciprofloxacin mechanism of action FreakingOut USMLE Step 1 Forum 3 04-21-2010 11:43 AM
Stridor and wheezing mechanism FSUSTC USMLE Step 2 CK Forum 3 03-12-2010 12:55 PM

RSS Feed
Find Us on Facebook
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.

USMLE® & other trade marks belong to their respective owners, read full disclaimer
USMLE Forums created under Creative Commons 3.0 License. (2009-2014)