In most applications, especially in vivo applications, it is necessary to know the specific isotype of the antibody being produced by a cell line. The facility offers isotyping of antibodies either using commercially available test strips, or a flow cytometry bead based assay.
Isotyping is available for mouse and rat antibodies using the test strips, but for only mouse antibodies using the flow cytometry bead based assay. Good correlation has been found using either of the assays.
The test strips work by dipping the end of the strip into the antibody solution. As the antibody is absorbed into the strip, bands (similar to a Western) appear at different points on the strip correlating to a specific isotype. Little volume of antibody is needed to perform this test
The benefit of the flow cytometry based assay is that you need very little volume of the test antibody to perform this assay. 50uL or less allows you to decifer up to 7 different mouse isotypes. Fluorescent beads are coated with a specific antibody to detect a specific isotype. You add your sample to the bead mixture, and then use a secondary antibody conjugated to PE to detect the test antibody on the surface of the bead. The isotype specific beads that are PE positive tell you what isotype the antibody is.