Ligation based HLA-B*27 typing.

We have established a ligation based typing method to detect HLA-B*27 alleles at the DNA level. The method requires amplification of exon 2 of the HLA-B locus from genomic DNA by the polymerase catalyzed chain reaction (PCR) using group specific primers. An aliquot of the PCR amplification product, heat stable ligase and a pair of oligonucleotide probes, designed to hybridize adjacently to HLA-B*27 specific sequences of the amplified DNA are subsequently thermocycled. If the probes are perfectly complementary they become ligated otherwise they stay separated. The ligation of probes can be detected through their different labels by an enzyme linked immunosorbent assay (ELISA). Ligation based detection of beta-actin sequences which have been co-amplified serves as positive control for each PCR reaction. We observed complete concordance when typing 76 HLA-B*27 positive and 107 HLA-B*27 negative individuals either by serology or by the ligation based approach. We conclude that ligation based typing is a reliable tool for the DNA based detection of HLA-B*27 alleles. The procedure allows automation to a large extent and should be easily applicable to the typing of other HLA-class I alleles.

[Isolation of H. pylori proteins and support for their suitability in serologic diagnoses]. / Isolierung von H.pylori-Proteinen und Beurteilung ihrer Eignung für den Einsatz in serologischen Diagnosesystemen.

H.pylori-proteins were separated using gel chromatographic methods. These antigens were tested for their suitability to detect H.pylori-specific antibodies. A complex of two proteins (62 kDa and 30 kDa) was a strong and specific antigen. A third protein (13 kDa) was a good but nonspecific antigen. Concerning these facts we compared two often used antigen preparations for serodiagnosing H.pylori-specific antibodies (acid-glycine preparation and sarcosyl-insoluble outer membrane proteins). The sarcosyl-insoluble material contains more specific antigens and lower levels of nonspecific proteins compared to the acid-glycine preparation. Based on these results we conclude that the outer membrane preparation seems to be more suitable for the serodiagnosing of H.pylori-specific antibodies.