Synthesis of β_1E and β_1C Components of Complement in Human Foetuses

Abstract

Work on the chemistry of human complement has led t o the identification of at least two components associated with @,-globulins. The serum protein associated with the fourth component of complement (C',) has recently been identified as @,,-globulin by Miiller-Eberhard & Biro [5]. One of the third component of complement (C'3a) has been shown t o be associated with @,,-globulin by Miiller-Eberhard et al. [el; evidence was obtained that @,,-globulin reacts with red cells in the EAC',,,.z state and that during this process, as well as after storage, i t is converted t o @,,-globulin [2, 41.The present investigation is concerned with the synthesis of these two components in human foetuses. Material a n d MethodsThe antiserum to /IlE and Plc-globulins was obtained as follows: rabbit red cells were first sensitized with EDTA-treated horse serum a t 37°C for 1 hour; the cells were then washed three times with buffered saline and incubated at 37°C for 30 minutes with human fresh serum which had been previously absorbed with rabbit red cells and treated with zymosan ( 1 ml serum/3 mg zymosan type A ) at 37°C. Several injections of red cells treated in this way were given intravenously to a rabbit.The rabbit serum (M64) was heated a t 56°C for 30 minutes and was then, if necessary, absorbed with human red cells, previously washed.The antiserum was tested with immunoelectrophoresis (Ionagar 0.8/100 ml, buffer I 0.05, pH 8.6) against fresh human serum; its reaction was compared by immunoelectrophoresis and by double diffusion in agar gel (Ouchterlony-plate method) with that obtained using an antiserum to PIE and PIC previously described [l].The specificity of the antiserum was also studied by testing it against red cells coated with antibody and various components of human complement. To obtain cells presumed to be in the state EAC',,, the method described by Harboe et a2.[2] was used; briefly (a) human red cells Le(a + b -)were incubated at 37°C for 90 minutes with EDTA-treated serum containing anti-Lea; the cells (EA) were then washed with buffered saline and (b) incubated at 37°C for 5 minutes with human serum previously treated with hydrazine to inactivate C'4. The cells (EAC',) were washed and (c) incubated for 15 minutes at 37" with human serum heated a t 56" for 30 minutes in order to supply only C', (EAC',.,). The red cells were washed and tested against serial doubling solution of the antiserum (M64), one drop of the suspension of red cells and one

Human complement C7 and C9 in fetal and newborn sera.

“…The studies of the ontogeny of complement so far published have shown that Cl, C3, C4, and C5 are produced by the human fetus at an early stage of gestation (Adinolfi and Gardner, 1967;Adinolfi, Gardner, and Wood, 1968;Gitlin and Biasucci, 1969;Colten, 1972, Kohler;1973).…”

Levels of Two Components of Complement (C‘4 and C’3) in Human Fetal and Newborn Sera

“…The levels of these two components of complement were measured by the single radial diffusion technique described by Kohler and Muller-Eberhard (1967). Rabbit antisera against c', and c', were used in preparing the agar gel plates (Adinolfi and Gardner 1967). The reference standard for C'4 contained 6 mg/lOO ml (Behringwerke AG, Germany) and that for C', contained 47 mg/100 ml.…”