Wednesday January 17, 2001
Murine IFN-γ is a cytokine produced by T-cells (as well as NK cells) that have been activated by antigens, mitogens or alloantigens. IFN-γ is a 15.6 kDa dimeric protein that can be used to up-regulate many lymphoid functions, such as the anti-tumor and anti-microbial responses of the immune system. More specifically, the responses of macrophages, NK cells and lymphocytes can be activated.
IFN-γ can also be used to up-regulate cell surface protein expression which includes the expression of MHC. I have used IFN-γ in order to up-regulate the expression of MHC class II and to increase the expression of cell surface proteins in a murine ovarian tumor cell line. The up-regulation of MHC class II was confirmed by labeling the cells with an anti-murine MHC class II antibody (PE-labeled) after a 48 hour incubation with 1ng/ml of IFN-γ in the cell media. Flow cytometry analysis was used to confirm the results. The ovarian tumor cell line upregulated MHC class II expression by 25%.
Pepro Tech’s Recombinant Murine IFN-γ is easily reconstituted in water and stored at -20°C. The instructions that come with product are easy to follow and include reconstitution suggestions as well as an expiration time for IFN-γ stored at 4°C. But perhaps the best thing about this product is the price. At $170 for 100µg, Peprotech offered the best deal our lab could find from a trusted source of murine cytokines.
However, the product information sheet does not include information on how long the reconstituted IFN-γ can be stored at -20°C and still retain biological activity. It also lacks clear instructions about the relationship between biological units and nanograms of IFN-γ. Most of the papers I reviewed contained information about IFN-γ using units instead of nanograms, thus, preliminary experiments had to be performed to determine the optimum concentration to use.
Alicia Racelis
Graduate Student
University of Alabama, Birmingham