The scale is set from 0 (red) to 1 1 (blue), as none of the sample comparisons yielded a negative correlation coefficient. in ACARs are associated with ethnicity and age. Thus, each individual ACAR is relatively unique, suggesting that individualized information could be useful in precision medicine for predicting and monitoring immune health and resistance to disease. Subject terms:Glycobiology, Antibodies == Introduction == Much of human immunity to microbes and other pathogens is generated against both protein and carbohydrate antigens, and many new vaccines targeting induction of microbial immunity rely on carbohydrate-based conjugate vaccines15. Yet, while the antigenicity of carbohydrates has long been appreciated in regard to Fn1 the ABO(H) antigens and related blood groups, the presence of other types of anti-carbohydrate antibodies (ACAs) has been both provocative and poorly understood. Pure polysaccharides are considered to be relatively weak antigens in mammals when used as immunogens alone or used independently of their expression on a microbe, as such free polysaccharides are often T cell-independent and generate a biased IgM response68. Some zwitterionic polysaccharides can directly induce T cell-dependent IgG anti-carbohydrate antibodies9,10, and ACAs to the gut microbiota have been identified11,12. Regardless of whether responses are T cell-independent or -dependent, the presence of a diverse array of IgG antibodies to carbohydrates has been observed in many preparations of IVIG, purified IgG products prepared from pooled human plasma and made available through many different commercial sources13. Thus, human serum collectively contains IgG that recognizes glycan antigens, including microbial polysaccharides, Itraconazole (Sporanox) ABO(H) blood groups, Lewis structures, P blood groups, and the -galactosyl antigen11,1322. There is uncertainty as to which isotype the anti-blood group antibodies in each individual are, as well as what the breadth of the repertoire of such ACAs might be; studies suggest that both IgM and IgG to the same carbohydrate antigens are found in some individuals, though they may Itraconazole (Sporanox) vary in relative ratios23,24. Recently, we identified individuals with primary antibody deficiencies (PADs) who lack IgG to carbohydrate antigens25, associated with their propensity for infections26and inability to develop immunity to many carbohydrate-based vaccines. As to the origin of ACAs in general, there is strong evidence that specific ACAs can be induced by exposure to or by infections with different organisms11,27,28. Examples include production of antibodies to GM1 ganglioside associated with Campylobacter infection and subsequent Guillain-Barr Syndrome2931, GD1b (lactone) associated with Lyme disease andBorrelia burgdorferiinfection32,33, Tn antigen associated withCryptosporidium parvuminfection34, and others3544. Thus, ACAs are biologically important, as they serve as primary defense toward microbial pathogens and are the target response to vaccines and vaccine components27,4547. The glycomes of all microbes, fungi, plants, and animals to which humans are exposed are highly complex and represent many millions of different glycan structures48,49. It might be predicted that highly individualistic differences in ACARs occur, since environmental exposures, including microbial exposure, are likely be unique to each individual. Such information may lead to novel insights into human health and personalized medicine, and perhaps address concerns Itraconazole (Sporanox) over the importance of vaccination. However, these types of studies have been difficult to implement, largely due to the lack of robust screening technologies. Recent technological developments have employed glycan microarray technology11,17,19,5052or other array-type strategies53,54to investigate unique individual ACARs. A few studies have focused on bacterial polysaccharides and blood group antigens18, and used either pooled sera or total immunoglobulins to assess the ACA diversity13,14on a population level. These studies, although typically focused on a relatively small number of glycans, nevertheless suggest that individuals may differ in specific ACAs depending on the antigen5557, and that some ACAs may be useful in monitoring disorders or transplant antigens21,50,58. Others have suggested that ACAs are only to short fragments of.