Antigen 85A is a member of the antigen 85 complex (Antigen 85A, B, C). The enzymes of the antigen 85 complex have mycolyltransferase activity and catalyze the synthesis of the very rich glycolipid of the mycobacterial cell wall, the cord factor (trehalose 6,6’-dimycolate, TDM). The cord factor is vital for the integrity of the mycobacterial cell wall and pathogenesis of the bacillus. TDM is synthesized from two molecules of trehalose-6’-monomycolate (TMM) by Antigen 85A.