Change in immunoreactive human hepatic triglyceride lipase (HTGL) mass and the shelf-life of the HTGL ELISA kit in long-term storage.

Objectives of this work are to study changes in the immunoreactive HTGL mass during storage under various conditions. In addition, the shelf-life of the HTGL ELISA kit was confirmed. The immunological reactivity of HTGL in PHP stored in the liquid, frozen, or lyophilized state was monitored using purified human PHP-HTGL as the standard material. Furthermore, the long-term stability of the HTGL ELISA kit was ascertained. The immunoreactive HTGL mass in the lyophilized PHP maintained its initial immunological reactivity for at least 26 months at 4 degrees C or lower. The other reagents included in the HTGL ELISA kit also have a long shelf-life when they are stored at 4 degrees C or less. HTGL in PHP was stabilized by lyophilization and can be used as the standard material for HTGL ELISA; the HTGL ELISA kit has a long shelf-life, i.e., more than two years.

[Studies on the antigenic stability of hepatic triglyceride lipase in human postheparin plasma during long-term storage].

The present study describes how to process human postheparin plasma (PHP) containing hepatic triglyceride lipase (HTGL) that is utilized as a standard material of HTGL for the quantification of HTGL mass in human plasma. The optimal storage conditions for PHP were established by monitoring the stability of HTGL molecules in PHP as an antigen, which was stored in the liquid, frozen, or lyophilized state, using purified human PHP-HTGL as the standard material and a commercial HTGL ELISA MARUPI kit, which is a direct sandwich enzyme-linked immunosorbent assay (ELISA). The HTGL ELISA MARUPI kit, for which the validity was confirmed by precision and dilution tests, showed that the immunoreactive mass of HTGL in lyophilized PHP remained stable for at least 12 months at a storage temperature of 4 degrees C or lower. These results indicate that lyophilized PHP stored at a temperature of less than 4 degrees C can be utilized as the standard material for the quantification of HTGL in human plasma using the HTGL ELISA MARUPI kit.