Pneumococcal Capsular Polysaccharide (PCP) Assays for measuring response to vaccination
IgG antibodies to Pneumococcal Capsular Polysaccharide (PCP) are produced by the immune system following infection with Streptococcus pnemoniae or in response to immunisation with the Pneumovax vaccine. The measurement of specific antibodies to PCP is important in the investigation of primary immunodeficiency.
Carbohydrate antigens, such as Pneumococcal Capsular Polysaccharide (PCP) antigen present on Streptococcus pneumoniae, produce a thymus independent response predominantly of IgG2 subclass.
Failure to produce the appropriate specific antibody response or the production of functionally inactive antibodies may lead to recurrent infections in patients. These patients may present with clinical signs of immunodeficiency but with apparently normal, or even increased, IgG and IgG subclass concentrations. In such cases, antibodies against specific antigens should be measured in samples taken pre-immunisation and post-immunisation with an appropriate vaccine.
ELISA / EIA for quantitation of PCP
Microwells are coated with Pneumovax™ vaccine containing 23 Streptococcus pneumoniae serotypes 1-5, 6B, 7F, 8, 9N, 9V, 10A, 11A, 12F, 14, 15B, 17F, 18C, 19F, 19A, 20, 22F, 23F and 33F (Danish nomenclature). These serotypes represent approximately 80% of commonly found virulent serotypes.
In approximately 30% of individuals the response to vaccination is attributable to C-polysaccharide (CPS) antibodies and not to specific anti-PCP antibodies. These C-polysaccharide antibodies confer limited protection against pneumococcal infection and therefore Binding Site assays incorporate CPS antibody absorption to remove them from the sample prior to testing.
Kits are available to measure the specific IgG or IgG2 levels in serum.
| PCP | Measuring Range (mg/L) | Analytical Sensitivity (mg/L) |
| IgG | 3.3 - 270 | 0.62 |
| IgG2 | 1.1 - 90 | 0.45 |
| Description | Pack | Code |
|---|---|---|
| VaccZyme™ PCP IgG* | 96 tests | MK012 |
| PCP IgG2** | 96 tests | MK013 |
* Please enquire regarding FDA status
** Research use only
Pneumovax™ is a trademark of Merck & Co, Inc, Rahway, NJ, USA.
VaccZyme™ is a trademark of The Binding Site Group Ltd, Birmingham, UK
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