Many techniques for the estimation of specific proteins measure light scattered by, or the turbidity of, suspensions of antigen:antibody aggregates formed in fluid-phase reactions. Although the shapes of reaction curves obtained are well documented,1 2 interpretation of the data in relation to the laws of light scattering and the mechanism of the antigen:antibody reaction are poorly described in the literature. Using photon correlation spectroscopy it has been shown that antigen:antibody complexes continue to grow in size even when no further increases in scatter intensity or turbidity are apparent.
References
1.
KillingsworthLMSavoryJ. Nephelometric studies of the precipitin reaction: A model system for specific protein measurements. Clin Chem1973; 19: 403–7
2.
DeverillIReevesWG. Light scattering and absorption—developments in immunology. J Immunol Methods1980; 38: 191–204
3.
PuseyPMKoppelDESchaeferDWCamerini-OteroRD. Intensity fluctuation spectroscopy of laser light scattered by solutions of spherical viruses: R17, QB BSV, PM2 and T7. I. Light scattering Technique. Biochemistry1974; 13: 952–60
