Ursula Rother

Activation of complement by radiographic contrast media: generation of chemotactic and anaphylatoxin activities.

Iodinated radiographic contrast media such as methylglucamine diatrizoate and sodium ioglycamate activate serum complement in vitro. This was shown by a dose-, time-, and temperature-dependent decrease of total hemolytic complement activity in normal human serum, consumption of C4 and C6 activity, conversion of C3 to C3b, and generation of C5-derived chemotactic and smooth muscle contracting activity. Complement activation was achieved even in sera depleted of immunoglobulin and properdin, which may indicate that contrast media induce complement activation by mechanisms different from the classical or alternative pathway.

Bithermic Complement Activation in Cryoglobulinaemic Serum

Abstract. Cryoglobulin precipitates of the mixed type, containing 19 S IgM and 7 S IgG gamma globulin, were isolated from a patient serum and the interaction with serum C was studied. Loss of C activity in human serum incubated with cryoprecipitate was accompanied by the generation of C3 activity in the cryoglobulin aggregates. Complete dissociation of cryoprecipitation and the interaction of the precipitates with C was achieved at temperatures below 22°C and above 32°C respectively. The normal C titre in fresh serum of a cryoglobulinaemic patient was significantly reduced in vitro by first cooling and then rewarming the serum. The possible pathogenic role of the bithermic C activation in cryoglobulinaemic vascular lesions is discussed.

Serum Complement Activity in Rat Recipients of Small and Massive Skin Allografts.

Summary The complement activity was determined in sera of recipients after reciprocal skin transplantation between two isogenic strains of BN and Lewis rats. Small or massive allografts did not significantly affect the pattern or the level of overall complement activity, despite the fact that these animal sera are known to bind complement in the cy to toxic reaction in vitro. A slight initial rise of the serum complement activity has been noted in most of the animals. This rise is attributed to a possible increase in production of serum protein elicited by bleeding. The results have been interpreted to rule out either an exhaustion or an inactivation of the complement system as a causative factor in the longevity of massive grafts.

Studies on complement defective rabbits. IV. Blood clearance of intravenously injected S. typhi by the reticuloendothelial system.

Summary Three rabbits with an hereditary defect of the classical third component of complement (absence of C′6) were intravenously injected with 3 × 109 heat-killed S. typhi 0 901 labeled with I131. The rates of blood clearance by the RES in these animals were found to be identical with the rates observed in normal rabbits. Ten minutes after the intravenous injection, 84% of the bacteria were found localized in the liver. It is concluded that the activity of C′6 is without influence on the removal of S. typhi from the blood stream by the RES. The nonparticipation of C′6 in the clearance mechanism distinguishes this reaction from the immune bactericidal action of rabbit serum against 5. typhi 0 901.