https://doi.org/10.1351/goldbook.12894
Antibody against universal features of a given constant (C) region isotype (such as $\upgamma\!$ or $\upmu\!$) of one species that is made by immunizing a member of another species with that isotype.
Note: Such antibodies will bind any antibody of that isotype, and are thus useful for detecting bound antibody molecules in immunoassays and other applications.