Sawitree Chiampanichayakul

Simple method for screening of α-thalassaemia 1 carriers

Abstractα-Thalassaemia 1 genetic disorder occurs when there is a deletion of two linked α-globin genes. The interaction between these abnormal genes leads to the most severe type of thalassaemia disease, haemoglobin (Hb) Bart’s hydrops fetalis. The identification of α-thalassaemia 1 carriers and genetic counselling are essential for the prevention and control of severe thalassaemia diseases. In this study, we have developed a rapid screening method for identifying α-thalassaemia 1. A sandwich-type immunochromatographic (IC) strip test was developed, using the generated monoclonal anti-Hb Bart’s antibody, to trace the Hb Bart’s in haemolysates. When assayed by our IC strip test, all α-thalassaemia 1, HbH disease, HbH-Constant Spring (H-CS) disease, HbH-CS and heterozygous HbE (CSEA) Bart’s disease, and homozygous α-thalassaemia 2 showed positive results. No false negative results were observed in these blood samples. In α-thalassaemia 2 heterozygotes, 83% of them showed positive reactivity. Among HbE (both homozygotes and heterozygotes), β-thalassaemia (heterozygotes, homozygotes and β-thalassaemia/HbE) and normal subjects, the IC strip test revealed negative reactivity of 100, 85 and 97%, respectively. These results indicate that this novel immunodiagnostic kit, in combination with red blood cell indices, is suitable for screening and ruling out mass populations for the presence of α-thalassaemia 1.

Production of monoclonal antibodies to P-glycoprotein: its application in detection of soluble and surface P-glycoprotein of leukemia patients

Multidrug resistance (MDR) in leukemia is commonly associated with the expression of a transmembrane protein, P-glycoprotein (P-gp). In this study, two monoclonal antibodies (mAbs) specific for the extracellular domain of P-gp were generated. By employing the generated mAbs, a two-color lysed whole blood flow cytometric method for surface P-gp and an efficient sandwich ELISA for soluble P-gp determinations were established. By using the established methods, surface and soluble P-gp were detected in several leukemia patients. The presence of soluble P-gp could be used to identify the P-gp surface expression patients. Detection of soluble P-gp reported provides a new basis that may lead to a better understanding of the MDR mechanism in leukemia.

β3 subunit of Na,K ATPase regulates T cell activation with no involvement of Na,K ATPase activity

Na,K ATPase plays an important role in the regulation of Na(+) and K(+) ions that are required for normal resting membrane potential and various cellular functions. Na,K ATPase is composed of two subunits, α and β subunits. Engagement of the β subunit by an agonistic monoclonal antibody (mAb) P-3E10 inhibited T cell activation and induced the G0/G1 cell cycle arrest. In addition, mAb P-3E10 decreased CD25 expression. The mAb P-3E10, however, did not inhibit the proliferation of cell lines and the phagocytosis activity of phagocytes, and did not interfere with the Na,K ATPase activity. These results indicate that mAb P-3E10 reacts to the β subunit and, as a consequence, brings about the regulation of the T cell activation without disturbing the Na,K pump activity. By sequential immunoprecipitation, we demonstrated the expression of the β3 subunit free form apart from the α subunit. In this study, we propose that the β3 subunits of Na,K ATPase are expressed separately from the α subunit, and play a role in regulation of the immune response.

Involvement of CD147 on multidrug resistance through the regulation of P-glycoprotein expression in K562/ADR leukemic cell line

The relationship between P-gp and CD147 in the regulation of MDR in leukemic cells has not been reported. This study aimed to investigate the correlation between CD147 and P-gp in the regulation of drug resistance in the K562/ADR leukemic cell line. The results showed that drug-resistant K562/ADR cells expressed significantly higher P-gp and CD147 levels than drug-free K562/ADR cells. To determine the regulatory effect of CD147 on P-gp expression, anti-CD147 antibody MEM-M6/6 significantly decreased P-gp and CD147 mRNA and protein levels. This is the first report to show that CD147 mediates MDR in leukemia through the regulation of P-gp expression.

Production and characterization of monoclonal antibodies against α-globin chain-containing human hemoglobins for detecting α-thalassemia disease.

ABSTRACT Monoclonal antibodies against α-globin containing human Hbs, named AMS-Alpha1 and AMS-Alpha 2, were produced by the hybridoma technique using spleen cells enriched by the newly developed B lymphocyte enrichment protocol. These two monoclonal antibodies were of IgM class, reacting to only intact form of human Hbs A, A2, E, and F, which contain α-globin chain. By the indirect ELISA, the AMS-Alpha1 and AMS-Alpha 2 quantified less amount of α-globin chain containing hemoglobins in HbH disease than the SEA-α thalassemia 1 carriers and normal individuals. It was thus anticipated that these monoclonal antibodies can be used for detecting Hb Bart’s hydrops fetalis in which no α-globin chain is produced.