Direct observation of UV-B radiation effect on antigen-antibody coupling using surface plasmon resonance

We studied the effect of UV irradiation on (non)specific bounding of bovine serum albumin (BSA) and mouse antiBSA immunoglobulin (IgG) using a surface plasmon resonance (SPR) apparatus Biosuplar-2 and special photodetectors. It was found that specific bounding of AG-AB complex is broken under UV irradiation. Contrary to this, UV irradiation of BSA layer before its contact with IgG did not demonstrate any peculiarities. On the basis of quantitative determination of kinetics of specific bounding and washing and precise measurement of photon flux, the product γσ of quantum yield γ and active centre cross-section σ was evaluated to be about 10−20 cm2. As the dimension of amino acid residues tryptophan and tyrosine is about 1 nm, we have concluded that the quantum yield of reaction is very small (about 0.001). This indicates at presence of a barrier for direct photochemical reaction between the interacting substances.