Specialty media are media that are optimized, chemically defined formulated for specific uses or cell lines for very specialized applications. Specialty media are sometimes modernized conceptions of classical media formulations; in this case, requirements for sera or glutamine supplementation are often reduced. Specialty formulations are available to support high-density suspension cultures and/or transfected cells. Examples of specific applications for which specialty media have been formulated include stable isotope labeling with amino acids in cell culture (SILAC), and mouse embryo work. An example of a bacterial species cultured with specialized media is the Lyme disease spirochete, Borrelia burgdorferi, while CD 293 is optimized for the growth of high-density suspension cultures of HEK 293 cells.