| Autor: |
Levesque, Philip M., Alwis, Uditha de |
| Zdroj: |
Human Vaccines; March 2005, Vol. 1 Issue: 2 p70-73, 4p |
| Abstrakt: |
The adsorption of three Streptococcus pneumoniae (Sp) vaccine antigens byaluminum-containing adjuvants was studied. The antigens showed high binding affinityisotherms with aluminum hydroxide adjuvant described by the Langmuir equation butvirtually no binding to aluminum phosphate adjuvant. The effects of ionic strength andethylene glycol were evaluated to determine whether electrostatic or hydrophobicinteractions were responsible for the observed binding to aluminum hydroxide, but nosignificant change in the adsorptive capacity was observed at either high ionic strengthnor high concentrations of ethylene glycol for any of the antigens. This indicates thatneither electrostatic nor hydrophobic interactions appear to be responsible for theobserved binding, which means that ligand exchange may be the primary mechanism forthis interaction. Further studies to evaluate the ability to elute a Sp antigen fromaluminum hydroxide using fibrinogen (adsorptive coefficient 2.2 mL/µg) as acompetitive protein resulted in evidence that Sp antigen follows the trend that proteinswith higher adsorptive coefficients are able to displace those with lower adsorptivecoefficients. It was also noted that the Sp antigens and ?-lactalbumin (adsorptivecoefficient 1.8 mL/µg) have similar adsorptive coefficients indicative of high affinitybinding isotherms but do not contain phosphate, which has previously been used toexplain ligand exchange for such proteins as ?-casein and hepatitis B surface antigen(HBsAg). Further investigations using ?-lactalbumin as a model protein may elucidatethe binding interaction between the antigens in this study and aluminum adjuvants. |
| Databáze: |
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