The recognition of bacterial or viral carbohydrate epitopes by antibodies can contribute to immune system–mediated protection against pathogenic microbes. However, the development of potent vaccines against microbial glycans has lagged because of a lack of understanding of how the immune system recognizes carbohydrate structures. In Science Translational Medicine, Schneider et al. describe a systems approach to screening the reactivity of human antibodies to an array of 610 distinct glycan structures. Commerially available intravenous immunglobulin G recognizes several hundred carbohydrate epitopes; the responses are mediated mainly by immunglobulin G2 but not exclusive to this antibody isotype. Notably, glycan structures terminated by galactose, N-acetylgalactosamine or N-acetylglucosamine are prominently recognized, but reactivity to terminal mannose, N–acetylneuraminic acid or the related N-glycolylneuraminic acid is absent or low. These findings indicate that recognition of carbohydrates is selective for the terminal structures of known microbial epitopes or their host glycan-attachment sites and is tolerant of self glycan structures. These findings lend insight into more rational design of glycoconjugate vaccines.

Sci. Transl. Med. 7, 269ra1 (2015)