VCA IgM
Enzyme ImmunoAssay (ELISA) for the quantitative or qualitative determination of IgM class antibodies to Epstein Barr Virus (EBV) Capsidic Antigen in human plasma and sera with the "capture" system.
- Epstein Barr Virus or EBV is the principal etiological agent of infectious mononucleosis, as well as a contributory factor in the etiology of Burkitt’s lymphoma and nasopharyngeal carcinoma, or NPC.
- A member of the family Herpesviridae, it has a worldwide distribution, such that 80 to 90% of all adults have been infected. Primary infections usually occur during the first decade of life. While childhood infections are mostly asymptomatic, 50 to 70% of young adults undergoing primary EBV infections show mild to severe illness.
- EBV may cause a persistent, latent infection which can be reactivated under immunosoppression or in AIDS affected patients. As humoral responses to primary EBV infections are quite rapid, the level and class of antibodies raised in most cases allow classification as to whether the patient is still susceptible, has a current or recent primary infection, had a past infection or may be having reactivated EBV infection.
- The detection of EBV-specific IgG, IgM and IgA antibodies to its major immunodominant antigens has become therefore an important and useful determination for the monitoring and follow-up of EBV infected patients.
The assay is based on the “IgM Capture” method and on affinity purified native VCA antigen.
Microplates are coated with a polyclonal anti-hIgM antibody that in the 1st incubation “captures” specifically this class of antibodies.
After washing out all the other components of the sample, in the 2nd incubation bound anti EBV-VCA IgM are detected by the addition of a complex formed by biotinilated affinity purified native VCA antigen and Streptavidine, labelled 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 IgM antibodies present in the sample and can be detected by an ELISA reader.
Quantification of IgM is made possible by a standard curve calibrated in arbitrary units, in absence of an international standard to refer to.
- Evans AS and Niederman JC, Am J Clin Pathol, 1982, 77(5): 555-60
- Fleisher GR, Collins M and Fager S, J Clin Microbiol, 1983, 17(4): 619-24
- Howitz CA, Henle G et al., Am J Med, 1977, 63(6): 947-57.
- Straus SE, Cohen JL, Tosato G et al., Ann Intern Med, 1993, 118(1): 45-58
- Engvall E. and Perlmann P.. J. Immunochemistry, 8, 871- 874, 1971
- Engvall E. and Perlmann P.. J.Immunol. 109, 129-135, 1971
- Volk W.A.. In “Essential of Medical Microbiology”. 2nd ed. pp 729, G.B.Lippincott Company, Philadelphia, New York, S.Josè, Toronto.
- Betts R.F. and al.. Journal of Infectious Diseases, 143:821- 826, 1981.
- Engelhard D. et al.. Journal of Infectious Diseases. 163.628- 630, 1991.
- Griffiths P.D. et al.. Journal of Infectious Diseases. 145. 647-653, 1982