Rubella Virus IgM μ-capture ELISA

GWB-1D2E67

Rubella is an enveloped RNA virus belonging to the togaviruses. It has a spherical shape measuring about 50-70 nm in diameter. There appears to be only one antigenic type and no cross-reactivity with alphaviruses or other members of the togavirus group has been found. Rubella viruses are pathogens of the respiratory tract and transmitted mainly by droplet infection. Rubella is a worldwide common contagious disease with mild constitutional symptoms and a generalized rush. In childhood it is an inconsequential illness but when it occurs during pregnancy there is a significant risk of severe damage to the fetus. The risk of congenital rubella depends primarily on the month of pregnancy in which infection is acquired: overall app. 16% of infants have major defects at birth following maternal rubella in the first 3 months of pregnancy. Congenital rubella infection may lead to a syndrome with single or multiple organ involvements known as embryopathia rubeolosa. In some cases infection is inapparent but results in consequential damages as eye defects deafness growth retardation and others. Naturally acquired immunity usually is long-lasting but reinfection is possible due to decreasing levels of circulating antibodies. For immunization a vaccine containing live virus is used. Infection may be identified byDetection of virus by PCR (prenatal)Hemagglutination inhibition (HAI) Haemolysis-in-gel test (HiG)Detection of antibodies by EIA ELISAMeasurement of antibodies in the serum is important for the determination of the immune status. Even a previous infection though rather overt may not yield a long-lasting immunity but may result in an antibody titer too low to prevent reinfection. Especially the screening of adolescents and young women should be a mandatory routine in prenatal care. Principles of the assay: The qualitative immunoenzymatic determination of IgM-class antibodies against Rubella Virus is based on the ELISA (Enzyme-linked Immunosorbent Assay) technique. The Rubella Virus IgM ELISA is an IgM & mu; -capture ELISA. The plates are coated with anti-human IgM. After washing the wells to remove all unbound sample material horseradish peroxidase labelled Rubella virus antigen conjugate is added. This conjugate binds to the captured Rubella-specific antibodies. The immune complex formed by the bound conjugate is visualized with Tetramethylbenzidine (TMB) substrate which gives a blue reaction product. The intensity of this product is proportional to the amount of Rubella-specific IgM antibodies in the specimen. Sulfuric acid is added to stop the reaction. This produces a yellow endpoint colour. Absorbance at 450 nm is read using an ELISA microwell plate reader. Storage and Stability: The reagents are stable up to the expiry date stated on the label when stored at 2. . . 8 & deg; C. Limitations of the Test: Bacterial contamination or repeated freeze-thaw cycles of the specimen may affect the absorbance values. Diagnosis of an infectious disease should not be established on the basis of a single test result. A precise diagnosis should take into consideration clinical history symptomatology as well as serological data. In immunocompromised patients and newborns serological data only have restricted value. References Reef Se. Frey Tk. Theall K. Aabernathy E. Burnett Cl. Icenogl J. McCauley Mm. Wharton M. The changing epidemiology of rubella in the 1990s: on the verge of elimination and new challenges for control and prevention. JAMA. 2002 Jan 23-30; 287(4):464-72. Mezzasoma L Bacarese-Hamilton T. Di Christina M. Rossi R. Bistoni F. Crisanti A. Antigen microarrays for serodiagnosis of infectious diseases. Clin Chem. 2002 Jan; 48(1):121-30. Cooper Lz. Current lessons from 20th century serosurveillance data on rubella. Clin Infect Dis. 2001 Oct 15; 33(8):1287. Signore C. Rubella. Prim. Care Update Ob Gyns. 2001 Jul; 8(4):133-137. Weber B. Current developments in the laboratory diagnosis of rubella. Bull Soc Sci Med Grand Duche Luxemb. 1997; 134(2):31-41. Thomas HI Barrett E Hesket LM Wynne A and Morgan-Capner P. Simultaneous IgM reactivity by EIA against more than one virus in measles parvovirus B19 and rubella infection; Journal of clinical Virology 1999 14: 107 ? 118. Pinsky NA Huddelston JM Jacobson RM Wollan PC and Poland GA. Effect of multiple freeze-thaw cycles on detection of measles mumps and rubella virus antibodies; Clin. Diagn. Lab. Immunol. 2003 10(1):19-21. Tipples GA Hamkar R Mohktari-Azad T Gray M Ball J Head C and Ratnam S; Evaluation of rubella IgM enzyme immunoassays. J. Clin. Virol. 2004 30:233-238.