ABSTRACT : MP 84 is a novel protein synthesized in response to all cytokines. this antigen is expressed only in stimulated mesangial cells and diseased kidney sections but not in the normal kidney sections (Mukhtar A, 1992 & 1994). This is the first study of the mechanism of MP 84 expression by stimulated mesangial cells by incubating cells with cyclohexmide (inhibitor of protein synthesis), tunicamycin (inhibitor of transcription) and actinomycin D (inhibitor of N-linked glycosylation). Anti phosphatase anti alkaline phosphatase (APAAP) was used. This study shows that both transcription and translation are required for expression since both cyclohexamide (inhibitor of protein translation) and actinomycin D (inhibitor of transcription) inhibited the target antigen.