Another ImmunoQ.

[Loanna]

Advertisement - Members don't see this ad

Hallo guys!I have a question I came across, and I can't understand the answer.
''In a mixed lymphocyte culture, lymphocytes from person X, homozygous for HLA-Dw7, are irradiated and then cultured with lymphocytes from person Z. DNA synthesis is NOT stimulated.What is the conclusion?''
The answer is that Z is homo- or hetero-zygous for HLA-Dw7.
Can anyone plz explain to me why?

 

[Doctor J]

Hallo guys!I have a question I came across, and I can't understand the answer.
''In a mixed lymphocyte culture, lymphocytes from person X, homozygous for HLA-Dw7, are irradiated and then cultured with lymphocytes from person Z. DNA synthesis is NOT stimulated.What is the conclusion?''
The answer is that Z is homo- or hetero-zygous for HLA-Dw7.
Can anyone plz explain to me why?

Lymphocytes from person X are not stimulated to divide because they were irradiated and any dividing lymphocytes will have DNA damage from the radiation and thus apoptose. Lymphocytes from person Z are not stimulated to divide because they come from an individual who 'presents' HLA-Dw7 MHC Class II molecules to all their lymphocytes normally, thus these lymphocytes are tolerant to the HLA-Dw7 molecules. The small peptide chain being presented in these MHC II's will be similar for both people, the basis of the fact that HLA identical bone marrow grafts have very low rejection or GVH rates.