The binding of kidney-bean phytohemagglutinin by Ehrlich ascites carcinoma

• Published in: Biochimica et biophysica acta. General subjects Vol. 97; no. 3; pp. 510 - 522
• Main Authors: Lyle Steck, Theodore, Hoelzl Wallach, Donald F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.1965
• Subjects: PHA; G.T.S; EAC
• ISSN: 0304-4165; 1872-8006
• DOI: 10.1016/0304-4165(65)90164-9

1. 1. The phytohemagglutinin of the red kidney bean agglutinates 3 types of erythrocytes, 4 reticuloendothelial cell types, and 3 mouse tumors with different avidity. Evidence is provided that these cell types have surface receptors in common which are responsible for their agglutination. 2. 2. The reaction of the phytohemagglutinin with Ehrlich ascites carcinoma cells was examined in detail. It was shown that the agglutination of this tumor is not a simple function of phytohemagglutinin binding, but depends upon the state of the cell surface. The affinity constant for the reaction of phytohemagglutinin with Ehrlich ascites carcinoma cells was found to be 1.8·10 7 at 1°. The binding affinity was maximal at 18° and diminished at higher temperatures. The 6.6·10 7 receptor sites per Ehrlich ascites carcinoma cell appeared to be located at the cell surface. 0.3% of the receptor sites had to be occupied before agglutination was observed. The velocity of phytohemagglutinin binding increased with temperature and concentration. The rate constant was observed to diminish as the reaction progressed; thus at 1°, it decreased from 2·10 3 to 0.5·10 3 l·moles −1·sec −1 during the first 30 min. 3. 3. The affinity constant for the reaction of phytomegglutinin with human erythrocytes was found to be 8.4·10 7·4% of the 5·10 5 binding sites per erythrocyte must be occupied for agglutination to be detectable. Erythrocytes treated with trypsin and neuraminidase showed increased agglutinability.