Establishment of an ELISA system for the determination of Japanese monkey calreticulin and its application to plasma samples in macaques.

BACKGROUND

Calreticulin (Crt) is a molecular chaperone in endoplasmic reticulum, assisting a correct folding of glycoproteins. Establishment of its assay method might be advantageous to determine the Crt level in cell or other biosystems.

METHODS

An enzyme-linked immunosorbent assay (ELISA) system for the determination of Crt of Japanese monkey, Macaca fuscata, was developed in this study. Japanese monkey Crt protein expressed in Escherichia coli was used as a standard protein.

RESULTS AND DISCUSSION: The assay was sensitive even to <10 ng/ml of Crt. Since the amino acid sequence of Crt is quite similar (99%, similarity) between the Japanese and rhesus monkeys, the ELISA was applied to the determination of plasma Crt in these two species in association with various diseases. The Crt level increased significantly in monkeys suffering from pneumonia and diarrhea, suggesting that the ELISA might be applicable for preliminary diagnosis of inflammatory disease.