Quantitative Determination of Hemagglutinins for Normal and Trypsinized Human Red Blood Cells

Summary

Erythrocyte stromata have been prepared by a variety of methods for use in quantitative determination of hemagglutinins for normal and trypsinized cells. The relative merit of the various methods has been discussed and a procedure for the preparation of a suitable antigen has been elaborated.

The course of agglutination as a function of the amount of normal stromata N added has been followed in rabbit anti-normal erythrocyte sera and in rabbit anti-trypsinized erythrocyte sera at pH 7.4 It has been noted that stromata are partially soluble at this pH.

The solubility of erythrocyte stromata has been determined in saline and in normal rabbit serum at various hydrogen ion concentrations and has been shown to be minimal at pH 5.5.

Quantitative estimation of total antibody for normal and trypsin treated cells has been carried out in both homologous and heterologous antisera at pH 5.5, and a moderately high degree of precision has been realized.

Results obtained by quantitative methods parallel those obtained in routine absorption studies, and offer strong support for the original contention that there are antigenic differences between normal and trypsin treated cells.

It has been suggested that incomplete antibodies in rabbit antiserum to human red cells agglutinate trypsinized cells because of the capacity to act as divalent molecules in reactions with such cells. Serologic similarities between these systems and those found in human sera in certain types of hemolytic anemia suggest a similar explanation for the incomplete antibody present.