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| 2. |
- Halverson, Gregory R, et al.
(författare)
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Murine monoclonal anti-s and other anti-glycophorin B antibodies resulting from immunizations with a GPB.s peptide.
- 2009
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Ingår i: Transfusion. - : Wiley. - 1537-2995 .- 0041-1132. ; 49, s. 485-494
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The blood group antigens S and s are defined by amino acids Met or Thr at position 29, respectively, on glycophorin B (GPB). Commercial anti-s reagents are expensive to produce because of the scarcity of human anti-s serum. Our aim was to develop hybridoma cell lines that secrete reagent-grade anti-s monoclonal antibodies (MoAbs) to supplement the supply of human anti-s reagents. STUDY DESIGN AND METHODS: Mice were immunized with the GPB(s) peptide sequence TKSTISSQTNGETGQLVHRF. Hybridomas were produced by fusing mouse splenocytes with mouse myeloma cells (X63.Ag8.653). Screening for antibody production was done on microtiter plates by hemagglutination. Characterization of the MoAbs was done by hemagglutination, immunoblotting, and epitope mapping. RESULTS: Eight immunoglobulin G MoAbs were identified. Five antibodies are specific by hemagglutination for s and two MoAbs, when diluted, are anti-S-like, but additional analyses shows a broad range of reactivity for GPB. Typing red blood cells (RBCs) for s from 35 donors was concordant with molecular analyses as were tests on RBCs with a positive direct antiglobulin test (DAT) from 15 patients. The anti-s MoAbs are most reactive with peptides containing the (31)QLVHRF(36) motif, with (29)Thr. By Pepscan analyses, the anti-S-like MoAbs reacted within the same regions as did anti-s, but independently of (29)Met. One antibody was defined serologically as anti-U; however, its epitope was identified as (21)ISSQT(25), a sequence common for both GPA and GPB. CONCLUSION: In addition to their value as typing reagents, these MoAbs can be used to phenotype RBCs with a positive DAT without pre-test chemical modification.
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- Wester, Elisabet Sjöberg, et al.
(författare)
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A simple screening assay for the most common JK*0 alleles revealed compound heterozygosity in Jk(a-b-) probands from Guam
- 2009
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Ingår i: Immunohematology. - 0894-203X. ; 25:4, s. 165-169
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Tidskriftsartikel (refereegranskat)abstract
- The Jk(a-b-) phenotype results from alterations in the JK gene and is characterized by absence of the RBC urea transporter in the cell membrane. The frequency of Jk(a-b-) varies among populations, but this phenotype is most commonly found in people of Polynesian and Finnish descent. Although rare, Jk(a-b-) individuals present a clinical challenge because anti-Jk3 is produced readily in response to transfusion and pregnancy, and Jk(a-b-) blood is not routinely available. Identification of Jk(a-b-) patients and donors is most often performed serologically. However, ten JK*o alleles have been identified, and this information can be used in DNA-based typing. We selected five JK*o alleles that had been encountered by our reference laboratory in two or more samples from unrelated individuals and designed an allele-specific primer PCR assay for use as an initial screening tool. After in-house validation, we tested genomic DNA from a family: a mother and her two sons referred to us for genetic investigation of their Jk(a-b-) phenotypes. Two different nucleotide substitutions, -1g>a in intron 5 (IVS5) and 956C>T in exon 10, originally associated with Polynesian and Indian/African populations respectively, were identified in the family. The mother and one son were compound heterozygotes, and the second son was homozygous for IVS5-1g>a. We conclude that the effort to design and validate such a screening assay was cost-efficient when compared with DNA sequencing costs. Furthermore, selection of the more common JK*o mutations was a practical approach that resulted in rapid identification of the genetic bases behind the Jk(a-b-) phenotypes in this unusual family. Although an obvious target for eventual inclusion into high-throughput genotyping platforms for clinical diagnostic services, current systems are very limited. Our approach provides a simple and inexpensive method for the identification of these rare alleles.
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| 4. |
- Wester, Elisabet S, et al.
(författare)
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Erythroid urea transporter deficiency due to novel JK(null) alleles
- 2008
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Ingår i: Transfusion. - : Wiley. - 1537-2995 .- 0041-1132. ; 48:2, s. 365-372
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The Kidd blood group antigens Jk(a) and Jk(b) are encoded by the red blood cell (RBC) urea transporter gene. Homozygosity for silent JK alleles results in the rare Jk(a-b-) phenotype. To date, seven JK(null) alleles have been identified, and of these, two are more frequent in the Polynesians and Finns. This study reports the identification of other JK(null) alleles in Jk(a-b-) individuals of different ethnic or geographic origins. STUDY DESIGN AND METHODS: Nine Jk(a-b-) samples and a sample from a Jk(a-b+) mother of a Jk(a+b-) baby were investigated. Polymerase chain reaction amplification and sequence analysis of the JK gene was performed. Western blotting and urea lysis were used to confirm Jk(a-b-) RBCs. RESULTS: Four novel alleles were identified: two different nonsense mutations, 202C > T (Gln68Stop) and 723delA (Ile262Stop) were identified on otherwise consensus JK*1 and JK*2 alleles, respectively. A missense mutation, 956C > T (Thr319Met), was identified in a JK*1 allele from an African-American and a JK*2 allele in two people of subcontinental Indian descent. Immunoblotting and urea lysis confirmed absence of JK glycoprotein in RBC membranes from a sample carrying the 956C > T mutation. Other previously described JK(null) mutations were found in samples of origins other than in which they were first identified. CONCLUSION: The molecular bases of the Jk(a-b-) phenotype are diverse and this is the first report of JK(null) alleles in individuals of African and subcontinental Indian descent. Although rare, these alleles should be taken into consideration when planning genotyping strategies for blood donors and patients.
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