[Thermodynamic study of the allohemagglutinins of the ABO system].

Many thermodynamic assays on natural allohemagglutinins ABO were undertaken by different authors. Our experiment concerns anti-A and anti-B. The allohemagglutinins level was determined by the Probit Method, using bromelin red blood cells and methyl cellulose, with an autoanalyser. This thermodynamic assay was carried out in almost the same conditions as those used by Wurmser. The data reveal an intraphenotypic (anti-A) or intra genotypic heterogeneity (anti-B) in the repartition of affinities. Average enthalpy changes are, in this methodology, interphenotypic (anti-A) and intergenotypic (anti-B) features. For Wurmser every genotype has a typical feature: so this author concludes a natural agglutinin homogeneity. Heterogeneity showed by our experimentation seems bound to the specific IgM and IgG repartition of each serum. Specific anti-A or anti-B IgM are more exothermic than specific IgG. The apparent disagreement must be interpreted owing to the fact that in N4 Wurmser's method, the only agglutinins determined are specific IgM.