DEVELOPMENT AND VALIDATION OF A SIMPLE ANTIGEN - ANTIBODY MODEL

A theoretical model for investigating physical phenomena underlying im mune complex formation was developed based on the statistical mechanic al theory of associating fluids that identifies each molecule as a har d sphere with a nested point charge and vector dipole. The interaction between binding molecules (epitope- paratope binding) is represented as a cone truncated by two concentric spheres in which the potential e nergy is a modified square well with respect to particle separation an d a square well with respect to mutual molecular orientation. Equilibr ium binding results predicted by the model show good agreement with re sults obtained experimentally for a model system containing a single a ntigen and a single monoclonal antibody [bovine serum albumin (BSA)-an ti-BSA antibody]. Moreover values obtained for the system isothermal c ompressibility and the second viral coefficient by both the model and light scattering experiments also show good agreement with one another .