Viruses, Serums, Toxins, and Analogous Products; Detection of Extraneous Agents by the Fluorescent Antibody Technique

We are amending the regulations concerning testing by the fluorescent antibody technique for extraneous agents (viruses) in cells of animal origin that are used in the manufacture of veterinary biologics. The amendment allows the use of alternative fluorochromes that may be conjugated to an antibody, revises the list of extraneous agents to be tested for, and includes extraneous agents for which equine cells are to be tested. In addition, the word ``agent'' is replaced with the word ``virus'' since this is the agent being tested for. The amendment is necessary to update the requirements related to the testing for extraneous viruses.