The Antigen-Antibody Reaction

[摘要] 1. 1. Computational analyses of quantitative immunodiffusion data are reported. Two alternative boundary conditions of the diffusion equation were used: a) free diffusion, i.e., diffusion of neither reactant, antigen or antibody, is influenced by the other, and b) existence of a “time-invariant sink” at the location where the zone of precipitation will form, i.e., antigen and antibody react only at that location, form complexes and eventually precipitate there. For the boundary condition of free diffusion, concentrations were computed for diffusion from a point source, as well as for diffusion from the area source. For the boundary condition of the time-invariant sink two solutions were derived and the computational results are given for both; one is an approximate solution which does not take into account the increased rate of diffusion which occurs as a consequence of the sink, and the other is an exact solution.2. 2. The amounts of antigen and antibody in the initial zone of precipitation were computed to be of the order of 10-7 g/cm.3. 3. It was found that for any given zone of precipitation the computed antibody-antigen ratios are independent of the assumed boundary conditions, provided the area source is considered in free diffusion. For the different zones of precipitation of each antigen-antibody system, i.e., at different initial concentration of reactants, computed antibody-antigen ratios were found to differ widely (for the egg albumin-rabbit anti-egg albumin system, for example, the computed antibody-antigen weight ratios vary between 4 and 40).4. 4. The results are interpreted to indicate that the assumed boundary conditions represent good first approximations to describe immunodiffusion, but that other processes besides those which were considered are also occurring, and that the extent of these processes depends upon the initial concentrations of antibody and antigen in the system. It is suggested that the principal process which occurs and which was not considered in the present analysis is, what was previously termed the “moving sink,” i.e., that antigen-antibody complex formation occurs at locations other than that where the initial zone of precipitation eventually becomes visible.5. 5. Required experimental data and a computational scheme are indicated which may permit a rigorous analysis of immunodiffusion.

[学科分类] 生物科学（综合）