Immunology: Practice Question

For HLA typing, which molecular technique involves DNA amplification by PCR using primers specific for the site of interest, followed by sequencing of these products, and provides the highest specificity?
  1. PCR-SBT (sequence based typing)
  2. PCR-SSP (sequence specific amplification)
  3. PCR-SSO (sequence-specific oligonucleotide)
  4. PCR-RFLP (restriction fragment length polymorphism)
Show Answer and Explanations

PCR-SBT (sequence based typing) — Correct answer

Correct. PCR SBT (sequence based typing) provides the highest specificity / resolution of the molecular HLA typing techniques. It involves PCR DNA amplification using primers specific for the site of interest, followed by sequencing of of these products.

PCR-SSP (sequence specific amplification)

Incorrect. PCR-SSP (sequence specific amplification) provides the fastest typing of the molecular techniques, but the lowest resolution - the resolution is similar to serological techniques. The DNA is amplified using sequence specific primers. If there is a match with the primer, it can be detected on a gel.

PCR-SSO (sequence-specific oligonucleotide)

Incorrect. PCR amplified DNA is hybridized to labeled sequence specific probes. It is best for high volume testing, such as screening for potential donors.

PCR-RFLP (restriction fragment length polymorphism)

Incorrect. DNA is amplified by PCR and digested by restriction enzymes. The alleles are identified by pattern.

Summary

Summary: PCR-SBT has the highest resolution. PCR-SSP is the fastest. PCR-SSO is best for high volumes.
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