Capsular polysaccharide adhesin antigen, preparation, purification and use
A substantially pure capsular exopolysaccharide adhesin of coagulase-negative staphylococcal strains, and a gonoral method to prepare such adhesins, are described. Vaccines composed of such adhesins, and uses of such adhesins to produce polyclonal and monoclonal antibodies against such adhesins, are also disclosed. The adhesins are useful in coating polymoric medical materials to prevent colonization by coagulase-negative staphylococcal strains, and as a probe in selecting desirable polymeric medical materials. Such adhesin antibodies are useful in vivo to prevent infection by nosocomial coagulase-negative staphylococcal strains, in assays for the detection of such bacteria, in assays for the estimation of such adhesins in complex mixtures, and as an affinity chromatography matrix.
1. A method of detecting the presence of a bacterium in a sample, the method comprising: contacting a sample with an isolated monoclonal antibody that binds to a substantially-pure coagulase-negative Staphylococcus epidermidis capsular polyssocharide adhesin antigen that binds to polymeric material, wherein said adhesin antigen inhibits, at a concentration of about 0.1 mg/ml, binding to said polymeric material of at least about 50% of cells of Staphylococcus epidermidis RP-62A, RP-62NA or F-3284, and detecting the presence or absence of binding of the antibody to the sample, wherein the binding of the antibody to the sample indicates the presence of a bacterium in the sample.
2. The method of claim 1 , wherein said adhesin antigen is obtained from a Staphylococcus epidermidis RP-62A culture using an isolation procedure comprising the following steps:
(a) extracting adhesin from a culture of bacterial stain RP-62A;
(b) digesting the adhesin;
(c) chromatographically separating said adhesin extract of (a) on an ion-exchange column;
(d) eluting a capsular polysaceharide from the column of(c) which binds to silastic materials and inhibits binding of Staphylococcus epidermidis RIP-62A, RP-62-NA, and F-3284 to said polymeric materials;
(e) chromatographically separating a capsular polysaccharide adhesin-containing fraction from (d) on an affinity column; and
(f) further purifying the capsular polysaccharide adhesin by chromatographing an adhesin-containing fraction from (e) on a molecular sieve column, and collecting material eluting between Kav of 0.0 to about 0.2.
3. The method of claim 1 , wherein the coagulase-negative Staphylococcus epidermidis capsular polysaccharide adhesin antigen inhibits, at a concentration of about 0.1 mg/ml, binding of at least about 50% of cells of Staphylococcus hominus.
4. The method of claim 1 , wherein the coagulase-negative Staphylococcus epidermidis capsular polysaccharide adhesin antigen inhibits, at a concentration of about 0.1 mg/ml, binding of at least about 50% of cells of a Staphylococcus epidermidis RP-12 bacterial swain.
5. The method of claim 3 , wherein the Staphylococcus hominus is an RP-14 bacterial strain.