Construction of ELISA System to Quantify Human ST2 Protein in Sera of Patients

Abstract

The human ST2 gene can be specifically induced by growth stimulation in fibroblastic cells, and can also be induced by antigen stimulation in Th2 cells. The gene encodes a soluble secreted protein, ST2, and a transmembrane protein, ST2L, which are closely related to the interleukin-1 receptor. To gain insight into the biological roles of the ST2 gene, three monoclonal antibodies (MAbs) against human ST2 gene products were obtained. To obtain these antibodies, immunization was carried out using two different immunogens: purified soluble human ST2 protein (hST2), and COS7 cells, which express the extracellular portion of human ST2L. 2A5 and FB9 MAbs were derived from the immunization with soluble hST2, and HB12 was derived from the COS7 cell immunization. All three antibodies were shown to detect native forms of the human ST2 gene products by immunoprecipitation, flow cytometry, and enzyme-linked immunosorbent assay (ELISA). In the competitive ELISA using biotinylated and nonlabelled MAbs, neither FB9 nor HB12 affected the binding of 2A5 to ST2 gene products. Based on this result, we constructed a sandwich ELISA system using 2A5 and FB9 to measure the concentration of soluble hST2 in sera. The ELISA, combined with the flow cytometry using these antibodies, will be a useful tool for elucidating the functions of human ST2 gene products in individuals.

Identification of Serum Soluble ST2 Receptor as a Novel Heart Failure Biomarker

“…ST2 is increased in the serum of asthma patients 5,6 and in some patients with autoimmune diseases. 24 ST2 levels in pleural effusions, but not serum, are increased in patients with lung cancer, in association with an increase in lymphocytes with Th2-dominance, compared with pleural effusions from patients with tuberculosis, which had local Th1 dominance and no increase in ST2.…”

“…4 The protein product of ST2 encodes a membrane receptor of the interleukin-1 receptor family and a truncated soluble receptor that can be detected in human serum. 5,6 Soluble ST2 is detected in the serum of patients early after acute myocardial infarction and inversely correlates with ejection fraction. 4 These findings suggest that ST2 is rapidly and transiently induced in humans and raise the hypothesis that soluble ST2 is increased chronically in patients with heart failure.…”

‘Repair’ Treg Cells in Tissue Injury

“…For example, Tregs directly induce anti-inflammatory macrophages, which contribute to tissue repair during the initiation, maintenance and resolution phases [12, 44-46]. Tregs produce high levels of IL-10, which act directly on fibroblasts [47]. Tregs decrease CXCL12 expression, which affects fibrocyte recruitment [48].…”

Expression and Regulation of ST2, an Interleukin-1 Receptor Family Member, in Cardiomyocytes and Myocardial Infarction

“…[13][14][15] Serum samples from days 1, 14, and 90 after MI from 69 randomly chosen patients in the HEART trial were assayed for soluble ST2 with a sandwich ELISA. 16 Serum ST2 levels in mice were measured with a sandwich ELISA using a rat monoclonal anti-mouse ST2 antibody (Morwell Diagnostics) and a rabbit polyclonal anti-mouse ST2 antibody. 17 …”