The Mouse IL-12 p70 Immunoassay contains recombinant mouse IL-12 expressed in Sf 21 insect cells using a baculovirus expression vector and antibodies raised against recombinant mouse IL-12. This immunoassay has been shown to accurately quantitate the recombinant factor. Results obtained using natural mouse IL-12 showed linear curves that were parallel to the Quantikine kit standards. These results indicate that this kit can be used to determine relative mass values for natural mouse IL-12 p70.