Embden, J.D.A. van

Analysis of rate of change of IS6110 RFLP patterns of Mycobacterium tuberculosis based on serial patient isolates (Article)

1999-12-01T00:00:00Z

The rate of change of IS6110 restriction fragment length polymorphism (RFLP) patterns of Mycobacterium tuberculosis was determined in serial isolates from 544 patients. In 25 patients (4.6%), the RFLP patterns of the follow-up isolates differed from the initial isolates. Patients with different follow-up strains were less likely to cluster with patients whose strains had indistinguishable RFLP patterns. Changes in RFLP patterns were more common for persons with extrapulmonary disease and for those who had both pulmonary and extrapulmonary isolates. Based on serial isolates spanning for the most part <3 months, the half-life was extrapolated to be 3.2 years (95% confidence interval, 2.1-5.0). The main implication of this study is that the rate of change of IS6110-based RFLP of M. tuberculosis supports the use of IS6110 typing in epidemiologic studies of recent transmission of tuberculosis.

Monoclonal antibodies to Treponema Pallidum. (Article)

1984-01-01T00:00:00Z

Three successive fusions of mouse myeloma cells and spleen lymphocytes of a mouse immunized with Treponema Pallidum resulted in one hybridoma producing anti T. pallidum antibodies for each fusion. The mice were immunized with live pallidum cells respectively 1, 3 and 5 months before fusion and with antigen purified on density gradients 4, 3 and 2 days before fusion. Hybridomas cultures were tested for antibody production with an Enzyme Linked Immunosorbent Assay (ELISA) and a Western blotting technique. Two of the three anti T. pallidum antibody producing hybridomas were found with the ELISA, the third was found with a Western blotting technique. These hybridomas were also tested for the production of antibodies to rabbit antigens and T. phagedenis antigens in the ELISA: none appeared to be positive. Two of the hybridomas produce antibodies to a T. pallidum protein antigen of a molecular weight of 46 000: one hybridoma produces antibodies to a T. pallidum protein antigen of a molecular weight of 44 000 as determined by the Western blotting. Antibodies against these antigens are found during almost all stages of syphilis in man. One of the hybridomas produces monoclonal antibodies that react with treponemal antigen from E. coli cells, prepared by recombinant DNA technology as appeared in the Western blotting technique and this antibody will be used for purification of the 44 000 protein.

Molecular cloning and expression of Treponema pallidum DNA in Escherichia coli K12. (Article)

1983-01-01T00:00:00Z

A gene bank of Treponema pallidum DNA in Escherichia coli K-12 was constructed by cloning SauI-cleaved T. pallidum DNA into the cosmid pHC79. Sixteen of 800 clones investigated produced one or more antigens that reacted with antibodies from syphilitic patients. According to the separation pattern of the antigens produced on sodium dodecyl sulfate-polyacrylamide gels, six different phenotypes were distinguished among these 16 clones. These antigens reacted also with anti-T. pallidum rabbit serum. No antibodies against the cloned antigens were found in normal rabbit serum and in nonsyphilitic human serum. The antigens produced by the E. coli K-12 recombinant DNA clones comigrated in sodium dodecyl sulfate-polyacrylamide gels with antigens extracted from T. pallidum bacteria, suggesting that the treponemal DNA is well expressed in E. coli K-12. Several of the cosmid recombinant plasmids have been subcloned, resulting in smaller T. pallidum recombinant plasmids which are more stably maintained in the cell and produce more treponemal antigen. Monoclonal antibodies were raised against T. pallidum, and one hybridoma produced antibodies that reacted not only with an antigen from T. pallidum but also with the antigen produced by one of the E. coli clones.