In HIV-infected MT-4 cells, L-lysine-α-oxidase, an inhibitor of HIV reproduction, selectively inhibits the synthesis of histone proteins, including 18K antigen (H2B histone). This protein is the target for autoimmune suppression of helper T cells. The enzyme has a low effect on the synthesis of other proteins and DNA. In addition to 18K antigen, L-lysine-α-oxidase suppresses the synthesis of high-molecular-weight proteins (270, 220, 140, 100, 75, 70, and 60 kD). ©1997 Plenum Publishing Corporation.