Changes in composition of IgM polymers in patients suffering from recurrent urinary bacterial infections after bacterial immunization treatment.

IgM is the first antibody produced during the immune response to infection or immunization, and it can be secreted as pentamer (containing a small polypeptide, termed as J chain) or hexamer (lacking J chain). In this paper we have analyzed structural characteristics (by electrophoresis and immunoblot) and anti-bacterial specificity (by enzyme-linked immunosorbent assay) of IgM antibodies purified from female patients suffering from recurrent bacterial infections of lower urinary tract and therapeutically immunized with the mixture of heat-inactivated uropathogenic bacteria. We report on changes in the composition of IgM polymers in tested patients. The immunization induced the raise of the levels of hexamers in patients that did not respond to immunization (non-responders), while the IgM polymers remained on the pentameric level in immunization dependent responders. We propose that the composition of IgM polymers could influence the immunization outcome and should be taken in count regarding the treatment of recurrent bacterial infections.