Carrageenan and Delayed Hypersensitivity II. Activation of Hageman Factor by Carrageenan and Its Possible Significance 1

Abstract

Carrageenan is a high molecular weight, long-chain polymer of sulfated galactose units that can be extracted from marine plants. Carrageenan has recently been shown to suppress the delayed hypersensitivity reactions of sensitized guinea pigs (1), inhibit the complement system (2, 3), damage macrophages in vitro (4) and in vivo (5), and induce kinin formation in rat plasma (6).

In this paper we show that carrageenan activates Hageman factor (factor XII) in human plasma, and thus promotes blood coagulation, induces vascular permeability, and liberates kinin (7). At higher concentrations it also acts as an anticoagulant, as reported previously (8).

Materials and Methods. Carrageenan was kindly supplied by Marine Colloids, Inc., Springfield, New Jersey as Seakem 21. The powder was dissolved in hot saline prior to use, using a double boiler technique.

Human platelet-deficient plasma was prepared in silicone coated plastic equipment. Venous blood was drawn into 30-ml plastic syringes, mixed with 0.1 vol of 0.13 M sodium citrate pH 5.0 in 40-ml Lusteroid tubes and centrifuged 30 min at 700g at 1°. Plasma was then transferred to thick-walled silicone coated Servall centrifuge tubes and centrifuged at 30,000g for 30 min. Plasma aliquots were then transferred to plastic, silicone coated containers and stored in the frozen state until use.

PTA-deficient, Christmas factor-deficient, and Hageman factor-deficient plasma was kindly provided by Dr. Oscar D. Ratnoff.

Barbital–saline buffer and DeJalon solution was prepared as described elsewhere (9, 10). Soybean trypsin inhibitor (SBTI) (Worthington) was freshly prepared in barbital–saline buffer at desired concentrations. O-Phenanthroline (Fisher) was prepared in barbital–saline buffer (2.5 × 10^–3 M) and stored at 4° for less than 2 weeks. Hexadimethrene bromide (Polybrene, Abbott Laboratories) was similarly prepared and stored. Anti-Hageman factor globulin was prepared as described previously (11) and kindly provided by Dr. Oscar D. Ratnoff.