Things I have always wondered and never understood about IMMUNOLOGY

[wade]

ALL nucleated cells present MHC class I.

 

1) B cells and macrophages nucleated, correct? therefore they should have MHC I and MHC II (since they are antigen presenting cells too) If not, why is it the NK cells don't kill them due to lack of MHC I?

 

 

 

2) Why don't NK cells kill our red blood cells since they are non nucleated?

 

 

 

3) What is the most abudant type of lymphocyte in the blood of a healthy individual?

 

 

I am an undergraduate student with hope of getting into medical school. These are NOT homework questions but rather just me trying to understand what I am missing here on the first 2 questions, along with the true answer for number 3. Thanks so much!

Edited March 7, 2011 by wade

[Greippi]

NK cells don't just go around killing anything that lacks self MHC molecules, their activity must be triggered by something. Self cells which lack the inhibitory signals, such as MHC 1 don't have stimulatory stuff, such as antibody bound to the outside of the cell, or some sort of altered self, for example.

 

 

That's your basic answer, I can go into more detail if you like.

 

The most abundant lymphocytes are CD4+ve - T helper cells. (The most abundant myeloid cells are neutrophils.)

Edited March 8, 2011 by Greippi