HLA typing

[Wachara Kasinreak]

Dear Netters;
I am working on HLA typing in Leprosy using PCR-based DNA typing 
technique. However, I have 2 questions which need help.
1. HLA-DQ genes of heterozygous individual which express 4 distinct DQ 
molecules , why in serological typing can define only 2 DQ antigens?
2. What is the property of MT-1 antisera? What is the amino acid binding 
region on HLA-DQw1 antigen which is specific to the MT-1 antibody?

Thanks in advance
Watchara