One-step molecular HLA-DR prescreening employing a set of 14 sequence specific oligonucleotides in a non-radioactive tetramethylammonium chloride hybridization protocol.

A novel non-radioactive protocol for molecular generic HLA-DR typing is introduced, employing sequence specific oligonucleotides (SSOs) enzymatically 3'-labelled with biotin-14-dATP via terminal deoxynucleotidyltransferase in a tetramethylammonium chloride hybridization procedure. The detection reaction is carried out, using streptavidin conjugated horseradish peroxidase which is bound to the SSOs, in combination with a light emitting detection system. Fourteen SSOs and one control SSO are employed for generic HLA-DR typing in a one-step protocol. In order to demonstrate the suitability of this procedure, 5 homozygous typing cell lines and samples of 11 pretyped individuals which include most serologically defined HLA-DR specificities (DR1, 2, 3, 4, 11, 12, 6, 7, 8, 9, 10, 52, and DR53) are analysed with the panel of 14 SSOs. The typing results show that this protocol, which avoids the use of radioisotopes, combines high specificity and easy handling. It also allows typing of poorly amplified samples because even after longer exposition times no false positive signals were observed and is particularly suitable for routine molecular HLA-DR typing on the generic level. In addition it can easily be adapted to DP and DQ typing or DR subtyping.