Summary
A polysaccharide from an unidentified species of Pseudomonas (PsP) has been shown to possess antigenic specificity similar to the Rho(D) antigen of human red cells. The following findings revealed this specificity: a) PsP inhibited anti-D agglutinins; b) anti-PsP rabbit sera contained both saline agglutinins and incomplete antibodies specific only for cells containing D antigen; c) D-positive cells absorbed specific agglutinins from anti-PsP sera; d) anti-D serum blocked agglutination of D cells by anti-PsP serum. Agglutination of D cells by anti-PsP rabbit serum was inhibited by N-acetylneuraminic acid (NANA) containing substances different from those previously shown to inhibit D cell agglutination by specific Rh antiserum. It was concluded that the antigenic similarity is not due to NANA but to some structure or linkage resembling it.
Footnotes
This work was supported by Grant E-3887 from the National Institute of Allergy and Infectious Diseases, and by Grants RG 4899 and WP 147, Division of Water Supply and Pollution Control, U.S.P.H.S.