The four major blood groups are based on whether or not you have two specific antigens — A and B. Doctors call this the ABO Blood Group System. The third kind of antigen is called the Rh factor.

The nanoparticle cores were formed by desolvating influenza M2e antigen and coating it with hemagglutinin (HA) antigen via biotin–streptavidin conjugation. LBL modification promoted nasal delivery and ...

which is the fundamental building block for the ABO blood group system. In normal individuals, the H antigen serves as the base structure for building A and B antigens. In Bombay blood group ...