The Standardization of the Cardiolipin-Lecithin-Cholesterol Antigen in the Precipitation Test for Syphilis

[摘要] Suspensions prepared from cardiolipin, alone or mixed with cholesterol, did not give any precipitation with reacting syphilitic human and rabbit sera. Suspensions prepared from lecithin alone or mixed with cholesterol gave only slight degrees of precipitation with reacting and nonreacting sera.In tests with pooled reacting human sera diluted in 0.85-per cent sodium chloride solution, suspensions prepared from mixtures of lecithin and cardiolipin showed marked precipitating activity, maximal when the lecithin:cardiolipin ratios ranged from 10:1 to 25:1 and the concentration of the total lipids was from 0.24 to 0.39 per cent. The addition of cholesterol to the lecithin and cardiolipin in the same range increased the reactivity approximately 2-fold. The optimal cholesterol:lecithin ratio was sharply defined as 0.33:1 and the concentration of the total lipids was from 0.415 to 0.63. Within the range of 10:1 to 25:1 ratios of lecithin:cardiolipin, the reactivity was dependent upon the concentration of total lipids whether cholesterol was present or not. Antigen-suspensions of like concentration and of very similar precipitating activities could be prepared from stock alcoholic solutions of different total lipid concentrations if the final proportions of alcohol and sodium chloride solution were maintained constant. In all of the experiments, certain quantitative relations between serum and antigen were demonstrated.In tests with undiluted reacting sera the optimal proportion of lecithin and cardiolipin was more sharply defined. A ratio of 25:1 and a cholesterol:lecithin ratio of 0.33:1 and a total lipid concentration of 1.03 per cent appeared to be optimal. Such a mixture was less subject to the phenomena of serum prozone reactions and inhibition of precipitation than other mixtures that were tested.

[学科分类] 生物科学（综合）