Expression of transcripts of complement components and their receptors during differentiation of embryonal carcinoma...

Based on our previous finding that TNF-alpha and TNF-beta can be expressed constitutively during early embryonal development [1], we extended our work to identify factors which are generally known to take part in inducing inflammation in adults. They can be regarded as candidate molecules involved in ontogenic inflammation during embryonal development. In this study, we chose the factors which are constituents of either a classical or an alternative pathway of a complement system and found that mRNAs corresponding to those of C2, C3, C4, C5 and to those of receptors CR1 and CR2 were expressed. Among them, mRNA expression of C3, C4, and CR1 was especially constitutive. Contrary to these observations, expression of two kinds of scavenger receptors (SR-I, SR-II) proved to be negative. In this report, the framework of ontogenic inflammation as a regulatory mechanism in embryonal development at the molecular level is discussed.