AT131 is MCDB 105 with trace elements, L-glutamine and 25mM HEPES buffer. MCDB 105 was formulated for rapid clonal growth of normal human diploid cells. MCDB media were developed for the low-protein and serum free growth of specific cell types using hormones, growth factors, trace elements and/or low levels of dialyzed fetal bovine serum protein (FBSP). MCDB 105 was formulated for rapid clonal growth of normal human diploid cells.