SYNTHESIS OF TWO COMPONENTS OF HUMAN COMPLEMENT, β1 H AND C3bINA, DURING FETAL LIFE

ABSTRACT. Adinolfi, M., Dobson, N. C. and Bradwell, A. R. (Paediatric Research Unit, The Prince Philip Research Laboratories, Guy's Hospital Medical School, London, and Immuno Diagnostic Research Laboratory, Department of Immunology, The Medical School, Birmingham, UK). Synthesis of two components of human complement, β1H and C3bINA, during fetal life. Acta Paediatr Scand, 70:705,.–The levels of β1H and C3MNA were estimated in sera from human fetuses, cord and maternal samples. Both components of complement were detected in fetuses more than 12 weeks old. The serum concentrations tended to increase with the gestational age. The mean levels of β1H and C3bINA in cord sera were near 54 and 61 % of the mean values in sera from normal adults. Elevated levels of β1H were observed in maternal sera at the end of the gestational period. When the levels of β1H and C3bINA were compared with those of two other components of complement, it was confirmed that the mean levels of C9 were low in fetal and newborn sera, while the serum concentrations of both C9 and Factor B were elevated in maternal samples. Newly synthesised β1H was detected in the culture fluids of fetal liver and peritoneal cells, as judged by the incorporation of labelled aminoaeids and the autoradiography of the specific immunoprecipi‐tates in agar gel.