Question

Describe SSO, SSP, and SBT test methods that can be performed to determine HLA type?

Answer 1

SSO - It stands for sequence specific oligonucleotide. In this method SSO probes are used where combination of PCR with hybridization is used with help of special type of probes. In this method, there is locus specific amplification of the genomic DNA segment that consists majority the polymorphic HLA sites. After the DNA is amplified, it is immobilized on the solid support followed by hybridization used SSO probes. The luminescence can be detected with help of fluorochromes. The resolution and understanding of HLA is better with higher number of probes.

SSP - Sequence specific primers

In this method, we try to identify if the primer is matched or mismatched in presence of template at the 3'end. Here there are two primers used for each of the two polymorphic sequence in cis which helps in easy identification of one or group of allele that are associated with the two polymorphic sequence motifs. It is mostly used for high level of HLA typing.


SBT - Sequence based typing
It is a critical method where there is complete sequencing through locus based specification PCR amplification generating templates. The amplified PCT products are divided in multiple reactions. It is a method which is used for higher resolution HLA typing.