Step I tuberculosis lymphocytes

Started by nurmd01
Your Residency Journey Starts Here
This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.
Get help with your application

Use all the free resources available to you from SDN: articles, guides, expert advising, forums discussions, and school research.

Browse articles Compare schools My application plan Read Interview Feedback
Practice for interviews Ask an Advisor
N

nurmd01

Full Member
7+ Year Member
Advertisement - Members don't see this ad
Why does lymphocytes increase in tuberculosis? The patogen in tuberculosis is a bacteria- mycobacterium tuberculosis- why doesnt neutrophils increase instead?
 
Sort by date Sort by votes
nurmd01 said:
Why does lymphocytes increase in tuberculosis? The patogen in tuberculosis is a bacteria- mycobacterium tuberculosis- why doesnt neutrophils increase instead?
Click to expand...
Mycobacteria are intracellular pathogens. So, it causes a TH1 response --> IFN gamma --> Macrophage activation --> Granuloma
IOW Cell-Mediated Immunity ( Macrophages, CD8+ cytotoxic T cells, NK cells) deals with intracellular pathogens.
Same goes with other facultative intracellular pathogens like Listeria, Histoplasma, Leishmania etc
Obligate intracellulars pathogens like viruses, rickettsiae, and chlamydiae are killed by cytotoxic T cells, natural killer cells, ADCC.
 
Last edited:
Upvote 0 Downvote
Advertisement - Members don't see this ad
Transposony said:
Mycobacteria are intracellular pathogens. So, it causes a TH1 response --> IFN gamma --> Macrophage activation --> Granuloma
IOW Cell-Mediated Immunity ( Macrophages, CD8+ cytotoxic T cells, NK cells) deals with intracellular pathogens.
Same goes with other facultative intracellular pathogens like Listeria, Histoplasma, Leishmania etc
Obligate intracellulars pathogens like viruses, rickettsiae, and chlamydiae are killed by cytotoxic T cells, natural killer cells, ADCC.
Click to expand...
nurmd01 said:
Why does lymphocytes increase in tuberculosis? The patogen in tuberculosis is a bacteria- mycobacterium tuberculosis- why doesnt neutrophils increase instead?
Click to expand...

Transposony has made a good point about the macrophage-T-lymphocyte "loop" that is exceedingly HY on Step 1.

Alveolar macrophage phagocytoses bacterium --> secretes IL-12 --> stimulates Th0 cells to become Th1 cells (and as Transposony has pointed out IL-12 also stimulates NK cells) --> Th1 cells secrete IFN-gamma --> increased macrophage activation --> cycle continues.

So macrophage --> IL-12 --> Th1 cell activation --> IFN-g --> more macrophage activation.

I was under an ICU consultant a few months ago who randomly asked me how Listeria is killed. Answer is increased CD8+ response (was an answer to a UWorld question since Listeria is facultative intracellular).
 
Upvote 0 Downvote
Phloston said:
I was under an ICU consultant a few months ago who randomly asked me how Listeria is killed. Answer is increased CD8+ response (was an answer to a UWorld question since Listeria is facultative intracellular).
Click to expand...

Yes! Listeria is one of those weird bugs that is gram+, but still has a cell mediated response. Also in another question, they try to treat it with a cephalosporin, but the correct answer is ampicillin. I kept screwing up those two questions until recently.

Also the CD marker for a macrophage is CD14, not CD8 or CD4, like I was expecting.
 
Upvote 0 Downvote
You must log in or register to reply here.