Anti-beta 2 Microglobulin Antibody [B2M-01] (PE) (A85544)

The prognosis of pediatric nephrotic syndrome (NS) correlates with the responsiveness to glucocorticoid therapy. Steroid-resistant NS (SRNS) patients progress to end-stage renal disease, while steroid-sensitive NS (SSNS) and steroid-dependent (SDNS) patients do not. We have performed proteomic profiling of urine samples from a cross section of pediatric and adolescent subjects with SSNS, SRNS, and orthostatic proteinuria (OP) to identify urinary biomarkers of steroid resistance. We performed surface-enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF MS) on urine from 19 subjects with SSNS/SDNS in remission, 14 with SSNS/SDNS in relapse, 5 with SRNS in relapse, and 6 with OP. Genetic algorithm search of principal component space revealed a group of five peaks distinguishing SRNS subjects, with mass/charge (m/z) values of 3,917.07, 4,155.53, 6,329.68, 7,036.96, and 11,117.4. Our analyses identified the peak at m/z 11,117.4 with an accuracy of 95% for classifying SRNS. Multidimensional protein fractionation and mass spectrometric analysis of SRNS urine samples combined with immunodepletion identified the 11,117.4 protein as beta2-microglobulin (B2M). Using an unbiased protein profiling approach, we have validated previously reported findings of B2M as a biomarker associated with SRNS. Prospective studies are warranted to establish additional biomarkers that would be predictive of SRNS.

A murine hybridoma cell line was obtained producing monoclonal antibody specific for human beta 2-microglobulin (beta 2m). The antibody reacts strongly with cell-associted human beta 2m, weakly with the cells of the monkey Cercopithecus aethiops, but not with any other non-primate cells tested. It is of IgG2a isotype, its pI is 6.9-7.1 and dissociation constant of its complex with soluble beta 2m is K = 1.5 X 10(-8) mol/l. The antibody also binds to beta 2m after electrophoretic separation under the reducing and denaturating conditions and blotting onto nitrocellulose. Immobilization of this antibody on Sepharose 4B yields an efficient immunosorbent for purification of beta 2m.