Tumour necrosis factor-α does not cross the rat placenta

In the last few years there has been a considerable proliferation of studies suggesting that tumour necrosis factor-α (TNF) has a very important physiological role in pregnancy. Its presence in the fetus has been related to several important roles such as cell growth and differentiation or immune protection. The aim of the present work was to analyze whether maternal TNF could reach the fetal circulation. The results found after in vivo [125I]TNF administration to pregnant rats at term demonstrate that TNF does not cross the placenta and therefore it may be suggested that the cytokine which is found in the fetus is synthesized in its organs.