Simultaneous formation of Tn antigen and anti-Tn antibody in mouse ovarian tissue and a new view of germline-encoded human anti-A blood group isoag-glutinin, considered as the "true" anti-Tn antibody

The human germline-encoded innate anti-A blood group isoagglutinin, expressed by penta- and/or hexameric IgM and inhibited by the <em>Helix pomatia</em>-reactive ovarian glycolipids of the C57BL/10 mouse (Arend, 1980) is unlikely to have arisen in response to A-allelic antigen activity. It most likely reflects nothing more than the monitoring of Tn-associated growth processes and can therefore be considered the “true” anti-Tn antibody.