Immunoblot technology uses antigens coated on membranes as a solid phase to detect specific antibodies in patient samples. The test performance is either manual, semi-, or fully automated. If a sample contains specific antibodies, those antibodies will bind to the membrane-bound antigens.
In the next step, an alkaline phosphatase (AP) labeled antibody (conjugate) is added, which binds to the specific antibodies. The alkaline phosphatase catalyzes a color reaction with the subsequently added nitro blue tetrazolium chloride/5-bromo-4-chloro-3-indolyl phosphate (NBT/BCIP). If specific antibodies are present in the patient sample, a dark line appears at the respective antigen position. The intensity of the resulting staining is proportional to the antibody concentration in the sample.
EUROLINE
EUROLINE immunoblots are multiparameter line blots that enable the generation of comprehensive, combined antibody profiles on one test strip. Membrane strips with multiple, purified, biochemically characterized antigens or antigen extracts as thin parallel lines serve as the antigen-containing solid phase.
The membranes are present as chips at exactly defined positions on plastic foils. The membrane strips do not contain superfluous proteins which may lead to nonspecific positive results. On every EUROLINE test strip, there is a control band that indicates whether the individual incubation steps have been performed. Automated evaluation of the immunoblots is performed by EUROLineScan software.
Westernblot and EUROLINE-WB
The Western Blot is the method of choice when positive results from a screening test (indirect immunofluorescence or ELISA) need further confirmation differentiation. Blot strips serve as an antigen-containing solid phase. They provide a base for antigen extracts separated electrophoretically according to molecular mass.
EUROLINE-WB assays are a combination of Western Blot and EUROLINE tests: The Western Blot strips undergo a coating of purified native or recombinant antigens in the form of membrane chips. The staining of the control band at the lower end of each strip indicates the correct performance of the individual incubation steps. Automated evaluation of the immunoblots is performed by EUROLineScan software.