Anti-mannans
Mannan (oligomannin) is a component of the yeast cell wall. Antibodies to yeast mannans are found at increased frequency in Crohn's disease and ASCA+ Crohn's tend to have lower low levels of mannan-binding lectin. Experimentally, antibodies to mannans from yeast can also crossreact to mannans of other types of yeast. Study of the sugars indicated that a mannotetraose (4-mer) was responsible for highest response. Studies of the 200 kDa glycoprotein antibodies found them commonly in healthy people, suggesting that the disease associated antibodies are to their carbohydrate moieties. Mannans from other yeast, for example candida albicans, have found to cross react with ASCA which suggests that other yeast may induce ASCA associated diseases.
Mannan-binding lectin (MBL) is a lectin produced by humans. In ASCA+ Crohn's disease the serum level of this protein is lower. Cellular response to mannan in ASCA+ peripheral blood lymphocytes could be inhibited by adding MBL, however, a high frequency of mutations in the MBL gene was found in ASCA+ patients.
Read more about this topic: Anti-saccharomyces Cerevisiae Antibodies