These antibodies are mainly IgM, which mostly react to Phosphorylcholine (PC), and are considered natural antibodies as they're present in non-immunized mice (or human newborns).
Try contacting Heinz Kohler, Sybille Müller or Srini Kaveri (the affiliation of the Dr. Kaveri is INSERM UMRS872(Eq.16) http://www.crcjussieu.fr/crc/index.php?cible=projet_equipe&id=16&spgmGal=equipes/16)