Abstract
With advance of protein chemistry, many phenomena of immunity have been explained from viewpoints of physical chemistry. Especially the introduction of the quantitative technique of estimating amounts of antigens and antibodies by Heidelberger has yielded important informations in this field. There are, however, many problems remained yet unsolved, one of which is the role of lipid in immunity reactions.
The effect of lipid extraction from antisera, without apparent denaturation of proteins, was first studied by Hartley, and his observations were extended and complemented more thoroughly by Horsf all and Goodner. According to these authors, the extraction of lipid from anti-pneumococcal horse sera with alcohol and ether in the cold resulted in the complete disappearance of agglutination and precipitation, and also rabbit antisera lost their agglutinating and precipitating ability after the extraction with alcohol, petroleum ether, and ether in the cold. In spite of the disappearance of visible reactions in vitro, the protective power of the extracted antisera was not reduced. Moreover the agglutinating and precipitating ability of the extracted horse serum was restored by the addition of lecithin, while that of the extracted rabbit serum was restored by cephalin. If an extracted serum was injected into the peritoneal cavity of mice and the peritoneal fluid was withdrawn after 30 minutes, this fluid was now able to agglutinate pneumococci.
It appears, therefore, that the extraction process deprives the antisera of their agglutinating and precipitating ability, but it has no influence upon the combining power of antibodies with antigens, and the addition of lipid restores the visible reactions in vitro.
In our experiment we undertook to decide, by means of quantitative method, whether, or not antibodies in the extracted sera were combined with antigens, when their agglutinating power was lost.
