Development and evaluation of a direct sandwich enzyme-linked immunosorbent assay for the quantification of guinea-pig immunoglobulin e.

The purpose of this study was to develop and evaluate a direct sandwich enzyme-linked immunosorbent assay (ELISA) for the immunoglobulin E (IgE) in serum and plasma from guinea pig using mouse monoclonal antibodies specific for guinea-pig IgE. Mouse monoclonal antibodies were raised against purified IgE protein. The ELISA was performed using a combination of two anti-IgE monoclonal antibodies. One antibody was labeled with horseradish peroxidase (HRP), and the other was coated on polystyrene wells. Purified guinea-pig IgE was used as the standard material. The validity of the ELISA was confirmed by precision, dilution, recovery, and interference tests. The range of detection was 3.1-800 ng of IgE mass per mL of serum and plasma. The intra- and inter-assay coefficients of variation were 4.6% and 5.7%, respectively, or less. The recovery test showed variation only between 92.1% and 111.8%, and the anticoagulants showed noninterference with the IgE assay. The mean serum IgE mass concentration in OVA-sensitized guinea pigs was 29438 ng/mL, and it was 48.6 ng/mL in normal guinea pigs. The present ELISA is useful and practical for specific measurement of the guinea-pig IgE, and it is surmised that it would be suitable for use in allergological and pharmacological research.

Pancreatic stone protein of pancreatic calculi in chronic calcified pancreatitis in man.

CONTEXT: The role of protein components of pancreatic secretions has been controversial in pancreatic stone formation. OBJECTIVE: To study the lithogenic role of pancreatic stone protein and lactoferrin in stone formation in chronic pancreatitis. PATIENTS: Pancreatic stones were collected from 13 patients with alcoholic (n=6) and nonalcoholic (n=7) chronic calcified pancreatitis. MAIN OUTCOME MEASURES: Pancreatic stone extracts were analyzed for pancreatic stone protein and lactoferrin using enzyme immunoassay. The localization of pancreatic stone protein immunoreactivity in the stone was observed using immunogold staining and scanning electron microscopy. RESULTS: Immunoreactivities for pancreatic stone protein were detected in the stones from all 13 patients with chronic calcified pancreatitis and for lactoferrin in the stones from five of the 13 patients. Pancreatic stone protein immunoreactivity distributed diffusely from the center to the periphery of the pancreatic stones. CONCLUSIONS: Involvement of pancreatic stone protein seems to be constant from the initial step of the stone formation to subsequent steps of the stone growth. However, pancreatic stone protein is only one of the precipitating proteins in pancreatic secretions such as lactoferrin, trypsinogen, etc.