Cyclic kinetics and mathematical expression of the primary immune response to soluble antigen

The conveyer hypothesis is based on the fact that because of clone predetermination, antibody production takes place in an organism without the presence of antigen as a result of natural cell differentiation. Soluble antigen is an analogue of a specific mitogen which gives rise to reproduction mainly of cells carrying on their surface the immunoglobulin receptors to the given antigen. The mathematical model of the conveyer hypothesis takes into account the initial conditions, among them the background level of antibody-producing cells before injection of a soluble antigen, migration of precursor cells in the draining lymphoid organ, and the rate of precursor differentiation, including the rate of the change of the immunoglobulin receptor number on the cell surface. Changes of antigen concentration in blood determine the intensity of precursor proliferation. Comparison of real experiments (intraperitoneal injection of capsular antigen ofPasteurella pestis into inbred mice) with calculations done on the basis of the developed mathematical model shows a definite qualitative resemblance with the kinetics of antibody-producing cells and free antibodies as well as with the decrease of free antigen concentration in blood. In spite of some differences between model experiments and real experiments the conveyer hypothesis and its mathematical model appear suitable for describing the primary immune response of mice immunized with low doses of capsular antigen ofPasteurella pestis.