Study on interactions of human IgG with immobilized anti-IgG or recombinant Staphylococcal protein A using surface plasmon resonance spectrometry

Abstract

Comparison of the IgG-binding activity of recombinant Staphylococcal protein A with introduced C-terminal cysteine residue (SPA-Cys) or goat anti-human IgG antibodies (anti-IgG) after their immobilization on a gold sensor surface of surface plasmon resonance (SPR) spectrometer. Methods. SPA-Cys or anti-IgG were immobilized on a gold sensor surface to form two variants of a bioselective element of the immunosensor. SPR spectrometry was used for the detection of IgG-binding activity of the immobilized proteins. Results. The SPR sensor response to the immobilization of anti-IgG was more than two times higher than that to the immobilization of SPA-Cys. However, there is almost the double advantage for SPA-Cys in the number of immobilized molecules. Moreover, the bioselective element of the immunosensor based on SPA-Cys showed a much better capability of binding IgG than the bioselective element based on anti-IgG. Conclusions. Comparison of immobilization of SPA-Cys or anti-IgG on the sensor surface of SPR spectrometer, and the interactions of immobilized proteins with human IgG demonstrated obvious advantages of SPA-Cys.

Study on efficiency of oriented immobilization of antibodies on the SPR sensor surface using Staphylococcal protein A or its recombinant analogue

“…SPR analysis was performed using a measuring flow-cell of the spectrometer "Plasmon-4m" (the device and corresponding software have been developed at the Lashkaryov Institute of Semiconductor Physics of the NAS of Ukraine) and a peristaltic pump "Ismatec" (Switzerland) at the pump speed of ~40 μl/min. The full procedure of SPR analysis is described in [12]. At first the measuring flow-cell was thoroughly washed by working buffer solution (PBS) to stabilize the SPR signal.…”