The expression of the NB1 antigen on myeloid precursors and neutrophils from children and umbilical cords

Abstract

The neutrophil-specific antigen NB1 is expressed by neutrophils from 97% of healthy adults. However, membrane expression of this molecule is unique in that it is found on only a subpopulation of neutrophils present in NB1-positive adults. We have investigated the ontogeny of NB1 antigen expression by haematopoietic progenitor cells to determine the stage and pattern of antigen expression during granulocytic cell differentiation. In addition, we examined whether the ontogeny and frequency of granulocytic cells expressing the NB1 antigen might vary in subjects according to age. A monoclonal antibody (MoAb) specific for NB1 (1B5) and flow cytometry was used to assess the frequency and characteristics of the NB1-positive cells found in umbilical cord blood (n = 11), children (n = 37), healthy adults (n = 46) and patients with chronic myelogenous leukaemia (n = 8). We also used flow cytometry to isolate NB1-positive and NB1-negative bone marrow and peripheral blood cells from various tissue sources. The separated subpopulations were then analysed by Wright stain and light microscopy. The size of the NB1-positive neutrophil subpopulation in 46 healthy adults (56 +/- 19%) was identical to that found for neutrophils from 36 children ranging in age from 8 months to 18 years (56 +/- 11%). In contrast, expression of the NB1 antigen by the neutrophils present in umbilical cord blood (91 +/- 3%, n = 11) was significantly greater than that in adults (P < 0.002) or children (P < 0.002). We also examined the size of the NB1-positive subpopulation among neutrophils from eight patients with chronic myelogenous leukaemia (CML). The NB1-positive subset in CML subjects (29.5 +/- 22.4%) was significantly less that in healthy adults (P < 0.02) or children (P < 0.02). Marrow cells from eight adults were similarly separated and analysed. We found that 69 +/- 17% of segmented and band forms of neutrophils, 70 +/- 2% of metamyelocytes and 61 +/- 23% of myelocytes were NB1-positive. In fetal bone marrow, 86 +/- 9% of the segmented and band forms, 82 +/- 10% of the metamyelocytes and 3 +/- 4% of myelocytes were NB1-positive. In conclusion, neutrophil-specific antigen NB1 is first expressed at the myelocyte stage of myeloid differentiation. In adult bone marrow, the percentages of myelocytes, metamyelocytes and segmented or band cells that expressed this antigen were similar and comparable in magnitude to the frequency of NB1-positive neutrophils found in the circulation. Although the size of the NB1-positive neutrophil subpopulation was the same in healthy adults and children, it was significantly increased in umbilical cord blood, and in fetal marrow cells.

Molecular basis of NB1 (HNA-2a, CD177) deficiency

“…[3][4][5][6][7][8][9] A special feature of NB1 is its expression on a neutrophil subpopulation. 10,11 Recently, we elucidated the primary structure of the NB1 glycoprotein. 12 A 1614-base pair (bp) cDNA codes for 437 amino acids (aa), of which 416 residues form an NH2-terminal extracellular protein with 2 cysteine-rich domains, 3 potential N-linked glycosylation sites, and a short segment including a glycosyl-phosphatidylinositol (GPI) attachment site.…”

The Use of Bioinformatics to Identify the Genomic Structure of the Gene That Encodes Neutrophil Antigen NB1, CD177

“…While NB1 and PRV-1 appear to be alleles of the same gene, some differences have been described in the expression of NB1 and PRV-1. NB1 gp is expressed by neutrophils and neutrophil precursors, but not by erythrocyte precursors or megakaryocytes (2,5,7). However, immunohistochemical staining of bone mar- row sections from patients with polycythemia vera showed that PRV-1 gp was expressed by early erythroblasts, megakaryocytes, promyelocytes, and myelocytes (13).…”

Flow Cytometry in Transfusion Medicine: Development, Strategies and Applications

“…in the investigation of transfusion-related acute lung injury (TRALI), in population studies or in the analysis of potential changes during pregnancy [122][123][124][125][126][127]. Moreover, functional and morphologic changes of circulating neutrophil cells during plateletpheresis were investigated using flow cytometry [128].…”