Product Information

RecomBlot Parvovirus B19 IgG/IgM   CB52/4402

 

RecomBlot

Qualitative in vitro test for the indirect detection and safe identification of pathogen specific antibodies. As a western blot the recomBlot serves to confirm the results from screening assays such as enzyme immuno assays (ELISA) or immunofluorescence assays (IFA). In contrast to ordinary immunoblot assays, the antigens are presented optimal in the recomBlot without disturbing and cross-reacting proteins. For this reason the recomBlot displays a high specificity and sensitivity. Furthermore the recomBlot is easy and secure to read

 

Immunoblot test with antigens produced by recombinant techniques for the detection of IgG or IgM antibodies against human Parvovirus B19

 

Human Parvovirus B19 occurs endemically worldwide. At intervals of several years, it causes epidemics in small areas from late fall to early summer, affecting kindergartens and schools in particular. The infection rate in children is between 15 and 30 % and in adults about 60 %.

 

The virus has a single stranded genome of about 5.6 kB and is packed in an icosahedral capsid, without a lipid layer, with a diameter of 22 nm. The two capsid proteins VP-1 and VP-2 are coded from the same reading frame. VP-1 is distinguished from VP-2 only by an additional N-terminal fragment. Furthermore, a nonstructural protein NS-1 is synthesized, which is required for virus replication and propagation in the cell.

 

Clinical spectrum of a Parvovirus B19 infection:

• Fifth disease (erythema infectiosum): It progresses in 20 % of cases without symptoms or with flu-like symptoms. Apart from the exanthema, polyarthralgia and a generalized swelling of the lymph nodes can occur occasionally.
• Aplastic crisis in patients suffering from hemolytic anemias.
• Spontaneous abortion/hydrops fetalis after infection during pregnancy.
• Persistent infection in immunosuppressed persons with chronic anemia and bone marrow depression.

The Western blot technique with the use of genetically engineered antigens allows at a glance the detection and identification of IgG and IgM antibodies against the different antigen classes. The distribution of reactivity provides an indication of the time of infection. The determination of antibodies against the NS-1 antigen can be helpful in the clarification of persistent Parvovirus B19 infections.

 

1. Product Advantages

• Recombinant antigens, therefore
  • Highest sensitivity and specificity
  • Easy and clear interpretation due to easy to read bands
• Easy test procedure; automation possible
• Save evaluation due to cut-off control
• Separate detection of IgG and IgM antibodies possible
• CE label: The recomBlot Parvovirus B19 test meets the high standard of the EC directive 98/79/EC on in vitro diagnostic medical devices
• Ideal addition as a confirmatory assay for the recomWell Parvovirus B19 tests

 

2. Recombinant Antigens

 

Parvovirus Antigens	Recombinant Ag	Size (kDa)
N-terminal half of structural proteins VP-1 and VP-2	VP-N	60
C-terminal half of structural proteins VP-1 and VP-2	VP-C	42
VP-1 specific segment (the region by which VP-1 differs from VP-2)	VP-1S	38
Nonstructural protein NS-1	NS-1	75

 

3. Test Principle and Procedure

1st Incubation:

A test strip loaded with Parvovirus B19 antigens is incubated with diluted serum or plasma in a dish for 10 - 16 h.

Wash 4 times

2nd Incubation:

Peroxidase conjugated anti-human antibodies (IgG- or IgMspecific) are added. Incubate for 1 h.

Wash 4 times

Color reaction:

5 - 10 minutes after addition of the coloring solution, insoluble colored bands develop at the sites on the test strips occupied by antibodies

 

4. Evaluation

Evaluation of recomBlot Parvovirus B19 IgG   IgG-ELISA Evaluation Positive (%) Negative (%) Equivocal (%) Total (%) Positive (%) 67 (74.4) 5 (5.6) 1 (1.1) 73 (81.1) Negative (%) 0 (0) 7 (7.8) 0 (0) 7 7(7.8) Equivocal (%) 6 (6.7) 4 (4.4) 0 (0) 10 (11.1) Total (%) 73 (81.1) 16 (17.8) 1 (1.1) 90 (100)

Evaluation of recomBlot Parvovirus B19 IgM

 

IgM-ELISA Evaluation	Positive (%)	Negative (%)	Equivocal (%)	Total (%)
Positive (%)	35 (38.9)	9 (10)	4 (4.4)	48 (53.3)
Negative (%)	0 (0)	34 (37.8)	2 (2.2)	36 (40)
Equivocal (%)	0 (0)	5 (5.6)	1 (1.1)	6 (6.7)
Total (%)	35 (38.9)	48 (53.3)	7 (7.8)	90 (100)

 

 

 

NS-1: Depending on the age, between 3 and 25 % of NS-1 positive samples are found in normal sera.

In patients with suspected persistent Parvo B19 infection and acute symptoms, the rate of NS-1 positive samples lies between 30 and 70 % (depending on the time of sample collection).

Poblozki et. al.: Antibodies to Parvovirus B19 NS-1 protein in infected individuals. J. Gen. Virology (1995), 76, 519-527

Poblozki et al.: Antibodies to the nonstructural protein of Parvovirus B19 in persistently infected patients: Implications for pathogenesis. J. Infect. Diseases (1995), 172, 1356-1359

 

5. Storage and Shelf Life

At 4 °C 18 months from the date of production

 

6. Commercial Product

Article No. 4402 recomBlot Parvovirus B19 IgG/IgM Reagents for 20 determinations