Analytic Study of the Differential Anticomplementary Effects of Dextran Sulphate and Heparin in the Assay for the Mouse Alternative Pathway

Abstract

In a recent paper, a linkage between immunological adjuvant activity in mice and in vitro anticomplementary (alternative pathway assay) effects was described for different polyanions. This connection was found only if mouse serum was used as a complement (C) source. In order to investigate the possible role of C in adjuvant activity, the differential effects of polyanions on mouse C were studied in detail. For this study, substances with different activity were selected, namely dextran sulphate with strong C-regulatory and immunoadjuvant activities, and heparin, which was weakly anticomplementary and devoid of adjuvant effect. In general, studies of mouse C are complicated by the inavailability of isolation procedures for the C-components involved. This difficulty was circumvented by making use of C5-deficient serum and of the haemolytic activity of mouse membrane attack complexes formed in the fluid phase. With yeast cells as alternative pathway activators it was shown that the effect of heparin on this pathway was restricted to activation of the terminal route. In contrast, dextran sulphate also caused a functional decay of a yeast-bound alternative pathway C5-convertase and interfered with the haemolytic activity of fluid-phase membrane attack complexes as well. Further studies will be needed to decide whether these specific effects of dextran sulphate are related to the immunological adjuvant activity of the substance in mice.

House dust extracts contain potent immunological adjuvants

“…The effect of complement could also be mediated by substances with, for example, adjuvant activity present in the antigenic or allergenic preparation. The latter is in line with findings of Klerx et al [12][13][14][15]20] suggesting that complement is involved in immunological adjuvant activity.…”

Study of the optimal reaction conditions for assay of the mouse alternative complement pathway

“…The optimal magnesium concentration, however, is in the same order as for the human ACP (Joiner et al, 1983). The concentration of 2.5 mM magnesium is half the concentration published before (Klerx et al, 1983) which was optimalized in the semi-microassay. The difference between the 2 optima may be due to surface effects.…”

“…The mechanism by which this is thought to occur is the formation of a fluid phase CoF-C5-convertase, which gives, again, indirectly rise to the phenomenon of bystander hemolysis (Pickering et al, 1969;Vogel and Mi~ller-Eberhard, 1984;Klerx et al, 1985). Obviously, the generation of the CoF-C5-convertase proceeded more slowly than the zymosan equivalent.…”

“…The assay to test mouse serum ACP activity was as recently described by Klerx et al (1983). In brief: in microtiter dishes with U-shaped wells (Greiner Labortechnik, Nt~rtingen, F.R.G.…”

“…Shortly after the discovery that human serum is able to lyse rabbit erythrocytes (RaE) via the alternative C pathway (ACP) (Platts-Mills and Ishizaka, 1974), however, it became clear that mouse serum is also able to do so and that this phenomenon can be used for assay of the ACP Van Dijk et al, 1980;Miletic et al, 1982;Klerx et al, 1983).…”