@article{arend_2016, 
  title={Natural anti-A and Tn-cross-reactive IgM arise from developmental O-GalNAc glycosylations.*}, 
  DOI={10.6084/m9.figshare.1279394.v334}, 
  abstractNote={While eukaryotic <i>O</i>-GalNAc-Ser/Thr
glycosylations do not occur in bacteria, the <i>O</i>-GalNAc glycan-bearing ovarian glycolipids, discovered in C57BL/10
mice, are complementary to the syngeneic, anti-A-reactive immunoglobulin M
(IgM), which does not appear in animals that have undergone ovariectomy prior
to the onset of puberty. These murine ovarian glycolipids are also complementary to the <i>Helix pomatia</i> agglutinin, which has emerged
from the protein coats of fertilized eggs of the snail and thus reveals the presence
of functional snail <i>O</i>-GalNAc glycans.The
hexameric structure of this lower eukaryotic, <i>Helix pomatia</i> agglutinin suggests evolutionary relationship to the mammalian
non-immune IgM molecule, which hypothetically obtains its complementarity from
the early trans-species <i>O</i>-GalNAc glycosylation of proteins and subsequent
GalNAc transferase depletion that completes the cell differentiation processes
and causes the release of <i>O</i>-glycan-depleted,
complementary proteins, such as secretory IgM revealing the structure of the volatilely
expressed, "lost" glycan carrier through germline-specific serine residues.
Consequently, the early or first <i>O</i>-GalNAc glycosylations of proteins
appear metabolically related to those of the mucin-type, "aberrant" monosaccharide
GalNAcα1-<i>O</i>-Ser/Thr-R,
also referred to as the Tn antigen, and explain the anti-Tn cross-reactivity of
anti-A-specific immunoglobulins and the pronounced occurrence of cross-reactive
anti-Tn antibody in plasma from humans with histo (blood) group O. In fact, in
human blood group O, A-allelic, phenotype-specific GalNAc glycosylation of
plasma proteins does not occur, affecting the levels of the anti-Tn antibody,
which may function as a growth regulator that, depending on its levels,
initiates a complex process of growth inhibition through enzyme-substrate
competition with subsequent trans-species <i>O</i>-GalNAc-glycosylations.}, 
  publisher={Figshare}, 
  author={Arend, Peter}, 
  year={2016}, 
  month={Dec}
  }