Official Step 1 HY Immunology Concepts & Discussion Thread

[Mr. Mojo Risin]

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Feel free to use this thread to discuss HY Immuno concepts. Good luck to everyone!

Links to the other HY subject threads:

Biochemistry: http://forums.studentdoctor.net/thr...y-biochem-concepts-discussion-thread.1115421/

Cardiology: http://forums.studentdoctor.net/thr...ardiology-concepts-discussion-thread.1115425/

Endocrinology: http://forums.studentdoctor.net/thr...crinology-concepts-discussion-thread.1115426/

Gastroenterology: http://forums.studentdoctor.net/thr...nterology-concepts-discussion-thread.1115427/

Hematology/Oncology: http://forums.studentdoctor.net/thr...-oncology-concepts-discussion-thread.1115428/

Microbiology: http://forums.studentdoctor.net/thr...-microbio-concepts-discussion-thread.1115422/

MSK/Skin/Connective Tissue: http://forums.studentdoctor.net/thr...ve-tissue-concepts-discussion-thread.1115430/

Neurology: http://forums.studentdoctor.net/thr...neurology-concepts-discussion-thread.1115431/

Psychiatry: http://forums.studentdoctor.net/thr...sychiatry-concepts-discussion-thread.1115432/

Renal: http://forums.studentdoctor.net/threads/official-step-1-hy-renal-concepts-discussion-thread.1115433/

Reproductive: http://forums.studentdoctor.net/thr...roductive-concepts-discussion-thread.1115434/

Respiratory: http://forums.studentdoctor.net/thr...spiratory-concepts-discussion-thread.1115435/

 

[faisal 2000]

hi guys
which antibody is predominantly present in first and second response to ascaris lumbricoides ??

 

[andrewsmack05]

on page 207 of First Aid 2015 --- it says that IL-4 enhances class switching to IgE and IgG. Is this true? In class we learned that that TGF-beta enhances class switching to IgA, IL-4 enhances to IgE, and IFN-gamma enhances to IgG.

 

[faisal 2000]

on page 207 of First Aid 2015 --- it says that IL-4 enhances class switching to IgE and IgG. Is this true? In class we learned that that TGF-beta enhances class switching to IgA, IL-4 enhances to IgE, and IFN-gamma enhances to IgG.

IFN-gamma produced by TH2 , eventually stimulates cell mediated immunity which (not deal with antibody)

 

[dfib slim]

IFN-gamma produced by TH2 , eventually stimulates cell mediated immunity which (not deal with antibody)

IFN gamma is produced mainly in TH1 cells, not TH2.

 

[dfib slim]

on page 207 of First Aid 2015 --- it says that IL-4 enhances class switching to IgE and IgG. Is this true? In class we learned that that TGF-beta enhances class switching to IgA, IL-4 enhances to IgE, and IFN-gamma enhances to IgG.

IL4 is released by TH2 cells and causes class switching to IgA and IgG. IFN gamma is released by TH1 cells and causes class switching to IgG. TGF beta inhibits T cell activation and is anti inflammatory. IL 5 causes class switching to IgA.

 

[faisal 2000]

IFN gamma is produced mainly in TH1 cells, not TH2.

yes you are right , it was typing mistake

 

[faisal 2000]

which antibody is predominantly present in first and second response to ascaris lumbricoides ??

 

[andrewsmack05]

IL4 is released by TH2 cells and causes class switching to IgA and IgG. IFN gamma is released by TH1 cells and causes class switching to IgG. TGF beta inhibits T cell activation and is anti inflammatory. IL 5 causes class switching to IgA.

IL-4 class switches to IgE too right? by Th2 cells

 

[dfib slim]

IL-4 class switches to IgE too right? by Th2 cells

You got it

 

[faisal 2000]

.

 

[faisal 2000]

as kaplan and fa mention IL-4 released by TH2 and causes class switch IGG and IGE , while IL-5 which released by TH2 will causes IGA
predominance of IGG and IGE depend on if there is bacteria or parasites isn't it ?

 

[faisal 2000]

Select from one of the following " the cell " that is of most importance in clearing a host cell infected with CMV .?

A NK cell

B CD4

C CD8

D Neutrophil

E T regulatory cells

# i know that adcc mechanism will kill cmv by binding of IGG to target cell and fc portion bind to NK cell and eventually lysis of target cell take place due to granzymes, lytic enzyme, and perforin , so i think the answer should be thing releated to IGG therefor i will go with cd4 but i am not sure about it

anyone have insight about this q ?

 

[faisal 2000]

if someone exposed to poison ivy that mean develop type iv hypersensitivity reaction isn't it ? how can his immunity develop type 1v in this condtion ?
phloston said hypersensitivity reaction develop in 2nd re exposure to poison ivy is that right ?

A type-IV hypersensitivity reaction requires previous exposure to the antigen in order to induce an immune response, just as a type-III does. In other words, if you're exposed to poison ivy and develop a rash, it means you had encountered it before without a reaction and then became sensitized. This first-time exposure is just an APC-CD4+ interaction, leading to the production of CD4+ cells that, in the future, can recognize the antigen again. The initial interaction is not called a hypersensitivity reaction; only the re-exposure is.

(Btw, I've encountered the poison ivy example, with re-exposure being necessary to induce the first hypersensitivity response, in both USMLE Rx and FA Q&A)

can anyone explain more

and does vaccination considered as type 3 hypersensitive reaction because it is arthus reaction

 

[dfib slim]

I saw an explanation in UWorld about how unlike other APCs, macrophages are unable to activate naive T cells and only activate memory and effector T cells.
I was under the impression that all APCs (B cells, dendritic cells, and macrophages) activate naive T cells. Any insight into this?

 

[seminoma]

I saw an explanation in UWorld about how unlike other APCs, macrophages are unable to activate naive T cells and only activate memory and effector T cells.
I was under the impression that all APCs (B cells, dendritic cells, and macrophages) activate naive T cells. Any insight into this?

Pretty sure you're right and UW is wrong.

http://www.ncbi.nlm.nih.gov/pubmed/16081773

if someone exposed to poison ivy that mean develop type iv hypersensitivity reaction isn't it ? how can his immunity develop type 1v in this condtion ?
phloston said hypersensitivity reaction develop in 2nd re exposure to poison ivy is that right ?


can anyone explain more

and does vaccination considered as type 3 hypersensitive reaction because it is arthus reaction

For poison ivy:
First exposure = sensitization
Subsequent exposures = reaction that follows the Type IV HSR mechanism.

This isn't any different from exposure to the type I HSR allergens. First exposure = sensitization (you make a bunch of IgE) then every subsequent exposure you have a reaction.

Vaccinations and arthus reaction aren't the same thing.