SYPH IgM
Enzyme ImmunoAssay (ELISA) for the determination of IgM antibodies to Treponema pallidum (Tp) in human plasma and sera.
Syphilis is a sexually transmitted disease caused by Treponema pallidum or Tp, bacterium belonging to the family of Spirochaetaceae. Tp is gram negative and is considered strictly anaerobe, exhibiting a characteristic mobility due to periplasmic flagella. A cell wall and a cytoplasmic membrane enclose the cytoplasmatic content.
Syphilis is a complex, acute, chronic infectious disease with diverse clinical manifestations, depending upon the stage of infection and the individual response. The period of incubation ranges from 10 days to 3 months and antibodies are usually detected after 2-4 weeks from the primary lesion.
Many assays have been developed for the immunological detection of the T.pallidum infection in the past (VDRL, TPHA, RPR) still currently in use at the diagnostic laboratory.
Recently, ELISA techniques have been applied to syphilis antibody screening in blood banks and Infectious Disease Departments, allowing the clinicians to use automatic analysis instruments and optical reading records.
Microplates are coated with Tp immunodominant synthetic antigens (recombinant p47, p17 and TmpA).
In the 1st incubation, the solid phase is treated with diluted samples and anti-Tp IgM are captured, if present, by the antigens.
After washing out all the other components of the sample, in the 2nd incubation bound anti-Tp IgM are detected by the addition of anti hIgM antibody, labeled with peroxidase (HRP).
The enzyme captured on the solid phase, acting on the substrate/chromogen mixture, generates an optical signal that is proportional to the amount of anti-Tp IgM antibodies present in the sample. The presence of IgM in the sample may therefore be determined by means of a cut-off value able to discriminate between negative and positive samples.
Neutralization of IgG anti-Tp, carried out directly in the well, is performed in the assay in order to block interferences due to this class of antibodies in the determination of IgM.
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