Changes in Composition of IgM Polymers in Patients Suffering from Recurrent Urinary Bacterial Infections after Bacterial Immunization Treatment

Abstract

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.

Antigenic specificity and expression of a natural idiotope on human pentameric and hexameric IgM polymers

“…Pentamers and hexamers isolated from sera of patients suffering with RUBI have been already characterized in our previous experiments, and our results have shown that these Abs were specific only to bacterial strains that were causing the infection, i.e., Proteus sp., Klebsiella sp. and E. coli (24).…”

“…Structural characteristics of IgM polymers purified from patients with RUBI were analyzed previously (24). In summary, IgM Abs purified from sera of Rs were shown to OD optical density, l/J relative ratios of l and J chain band intensities High l/J value indicates the predominance of hexameric IgM, while low l/J value indicates the predominance of pentameric IgM be pentameric, and their structure was preserved even after immunization with heat-inactivated bacteria.…”

“…Structural characteristics of IgM Abs purified from sera of patients with Waldenström's macroglobulinemia were determined using nonreducing SDS-polyacrylamide gel electrophoresis (PAGE) or SDS-urea PAGE and subsequent immunoblot with anti-J chain and anti-l chain specific Abs, as previously described (24). Briefly, nonreducing SDS-PAGE was performed on gels containing 4% of polyacrylamide strengthened with 0.5% agarose, and the gels were stained with Coomassie Brilliant Blue stain, using the standard staining procedure.…”

“…In addition to these Abs, we have also tested the antigenic specificity and expression of a natural Id on polymeric IgM Abs purified from 14 patients suffering from uncomplicated recurrent bacterial infections of lower urinary tract (RUBI) and undergone heat-inactivated bacterial immunization treatment. We have already shown that these Abs exert different structural characteristics (24). Namely, IgM polymers originating from patients in whom the vaccination process was unsuccessful (nonresponders, nRs) were mainly hexameric, which was more pronounced after the treatment with heat-inactivated bacteria.…”

“…On the other hand, IgM Abs of patients that positively responded to immunization (responders, Rs), retained the pentameric form. Since all other characteristics of these Abs (antibody titers, antigenic specificity and binding affinity) were essentially the same (24,25), the structural difference of Rs' and nRs' IgM polymers was designated as probable cause of different immunization outcome in tested RUBI patients.…”