Posts Tagged ‘Diagnosis of Epstein-Barr Virus Infection’
Diagnosis of Epstein-Barr Virus Infection (IV)
Recently ELISA methods are applied to the diagnosis of EBV infection. The methods using cellular extracts from cells transformed by the virus do not apply to this virus since they are highly nonspecific.
Alternatively we have used both purified proteins, synthetic peptides and recombinant proteins. GP125 has been used purified from P3HR1 line with which it has obtained 95% sensitivity and specificity of 100%.
In regard to the use of synthetic peptides, was applied to p62, whose sequence corresponds to a region of EBNA1, to develop a test to differentiate IgM and IgG responses.
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Diagnosis of Epstein-Barr Virus Infection (III)
The IFAC method for anti-EBNA is applied to heat-inactivated samples (56 º C, 30 min). A critical aspect in the determination of antibodies to EBNA is that the wells should not be dry between incubations, as you can get false negative results.
With these techniques in the course of primary infection occurring anti-VCA responses, both IgM and IgG isotype, in a virtually simultaneous. In most cases reach the peak in the time symptoms appear, or a few days later, so in most cases it is possible to detect IgG seroconversion. Between 2 and 3 months after onset of illness, the IgM response falls to undetectable levels, while IgG remains at good levels throughout the life of the individual. Read the rest of this entry »
Diagnosis of Epstein-Barr Virus Infection (II)
photo source: www.iac.rm.cnr.it
EBV has a complex antigen. Are three classes of antigenic systems: the latent phase antigens, antigens early replicative and late antigens. Not all are important for diagnosis. Among the former, there are the EBV nuclear antigens (EBNA1 and 2). Despite being the first to receive the antibody response to EBNA-1, which occurs in all infected individuals, is a late marker of infection. Among the early antigens (EA) and depending on your location there are two types: diffuse (EA-D in the nucleus and cytoplasm) and restricted (EA-R, only in cytoplasm).
The response of anti-EA is not universal and indicates that the cell has entered a lytic cycle and producer. Finally, among the late ones, the antigen of the virus capsid (VCA) is expressed equally abundantly in the lytic and productive infection, and induces a response of the IgM isotype in the primary disease that lasts 2-3 months, and IgG isotype , which remains detectable for life. Read the rest of this entry »
Diagnosis of Epstein-Barr Virus Infection (I)
photo source: http://bioweb.uwlax.edu/
In general, the best procedure for laboratory diagnosis of viral infections is isolation of the virus or any of its components or products. While acknowledging cell types naturally susceptible to infection by EBV in vitro is reduced to B cells, which are processed in a technologically complex and slow process, so that isolation is an imp procedure for most laboratories diagnostics.
The identification of either virus antigens has proved an adequate approximation. Finally, the detection of HBV DNA by the chain reaction of polymerase has shown a good performance comparative serological studies for the diagnosis of mononucleosis in the acute phase. Read the rest of this entry »