Sendai virus

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A paramyxovirus that causes respiratory tract infections in mice, rats, and other mammals, used in the laboratory to induce the formation of hybridoma cells that produce monoclonal antibodies.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun a virus, of genus Paramyxovirus, found in mice but is not pathogenic for humans; it has the ability to generate heterokaryons by fusing cells