The evaluation of histo-blood group ABO typing by flow cytometric and PCR-amplification of specific alleles analyses and their application in clinical laboratories

ABO genotyping of various hematopoietic cell lines to select model cells for research purposes

Various cells from humans and animals have been established as cell lines, and their features, characteristics, and origins have been reported. Many laboratories use cell lines as model cells, which are selected to suit research purposes. We attempted to identify the ABO genotypes of 31 human leukemia and lymphoma cell lines stored in our laboratory using three methods: the PCR amplification of specific alleles (PASA), PCR-restriction fragment length polymorphism (RFLP), and the direct DNA sequencing of PCR products. We distinguished 31 human leukemia and lymphoma cell lines examined into six major ABO genotypes: A/O (A101/O01: n = 1, A101/O12: n = 4, A101/O26: n = 1, A101/O49: n = 1, A102/O01: n = 3), A/A (A101/A101: n = 1, A102/A102: n = 2), B/O (Bw29/O01: n = 1), B/B (B101/B101: n = 2), O/O (O01/O01: n = 9, O01/O02: n = 1, O01/O26: n = 1, O02/O03: n = 1), and A/B (A102/B101: n = 3). To the best of our knowledge, this is the first study to identify the ABO genotypes of various cell lines. The ABO genotypes of cell lines are important when selecting an experimental model cell for an ABO blood group study, and are essential information for cell lines. These results may be employed by research and clinical laboratories as well as in the forensic field.

Rapid rare ABO blood typing using a single PCR based on a multiplex SNaPshot reaction

BACKGROUND

ABO subgroups would be considered when discrepancies in ABO grouping occur. Serological methods including adsorption-elution test, salivary ABH inhibition test, and anti-A1 (lectin) saline method could be used. However, these serological methods are laboring and obscure. Therefore, reliable and affordable method to assess the ABO subgroups is of particular interest.

METHODS

To solve this problem, the multiplex SNaPshot-based assays were designed to determine rare A and B subgroups. Primers used as probes for determination of rare ABO blood groups known in Taiwanese population were designed. Many ABO subtype samples were used to validate the accuracy and reproducibility of our SNaPshot panel.

RESULTS

A panel of primer probes were successfully designed in determining 8 SNP sites (261, 539, 838, 820, 745, 664, IVS6 +5, and 829 in exon 6 and 7) for A phenotype and 6 SNP sites (261, 796, IVS3 +5, 247, 523, and 502 in exon 2, 6 and 7 and intron 3) for B phenotype. SNaPshot analysis for defining blood group A alleles (A₁, A₂, A₃, A_m and A_el) and blood group B alleles (B₁, B₃, B_w and B_el) was therefore available.

CONCLUSION

SNaPshot analysis could be used in reference laboratories for typing known rare subgroups of A and B without DNA cloning and traditional sequencing. Moreover, this method would help to construct databases of genotyped blood donors, and it potentially plays a role in determining fetal-maternal ABO incompatibility.

Blood group antigen studies using CdTe quantum dots and flow cytometry

New methods of analysis involving semiconductor nanocrystals (quantum dots [QDs]) as fluorescent probes have been highlighted in life science. QDs present some advantages when compared to organic dyes, such as size-tunable emission spectra, broad absorption bands, and principally exceptional resistance to photobleaching. Methods applying QDs can be simple, not laborious, and can present high sensibility, allowing biomolecule identification and quantification with high specificity. In this context, the aim of this work was to apply dual-color CdTe QDs to quantify red blood cell (RBC) antigen expression on cell surface by flow cytometric analysis. QDs were conjugated to anti-A or anti-B monoclonal antibodies, as well as to the anti-H (Ulex europaeus I) lectin, to investigate RBCs of A₁, B, A₁B, O, A₂, and A_weak donors. Bioconjugates were capable of distinguishing the different expressions of RBC antigens, both by labeling efficiency and by flow cytometry histogram profile. Furthermore, results showed that RBCs from A_weak donors present fewer amounts of A antigens and higher amounts of H, when compared to A₁ RBCs. In the A group, the amount of A antigens decreased as A₁ > A₃ > A_X = A_el, while H antigens were A_X = A_el > A₁. Bioconjugates presented stability and remained active for at least 6 months. In conclusion, this methodology with high sensibility and specificity can be applied to study a variety of RBC antigens, and, as a quantitative tool, can help in achieving a better comprehension of the antigen expression patterns on RBC membranes.