POTENTIAL ROLES FOR TUMOR-NECROSIS-FACTOR-ALPHA DURING EMBRYONIC-DEVELOPMENT

This paper reviews the evidence indicating possible roles for tumour n ecrosis factor-alpha (TNF alpha) in development. It is proposed that T NF alpha may have essentially three major roles during embryonic devel opment, which may be analogous to its roles in the immune system and d uring inflammation: a role in programmed cell death; a role as a cellu lar growth and differentiation factor; and also a role in the remodell ing of extracellular matrix, and the regulation of cell adhesion molec ules and integrins. The concept of the existence of a cytokine array d uring embryogenesis, analogous to that occurring in inflammation, is d iscussed, as well as potential roles for TNF alpha in the induction of ubiquitin; protective mechanisms embryonic cells may employ against T NF alpha-mediated cytotoxicity; and a consideration of the role TNF al pha may play in a ''free radical theory of development''.