The Affinity Kinetics Study Between Antigen And Antibody In The Process Using BSA To Immune Animals

Antibody, which can specially combine with the antigen,is a kind of immunoglobulin secreted by plasma cells derived from B lymphocyte cells when the immunity systems of human beings or animals are stimulated by the antigen. Using BSA as the antigen to immune mice and rabbits continuously and at intervals, through analyzing the immune response process including continuous and interval immunity of mice and rabbits, we studied the production level of antibodies and affinity mature kinetic characteristics of antibodies by different immunity methods. With the increase of immunity times, the continuous antigen signals make the special antibodies always maintain a high level in vivo. We accounted the affinity constant of antibody under different immunity period by the ELISA method of carbamide lavation founded by ourselves. The results indicated that there was an obvious change process of antibody affinity after the second immunity response. The affinity constant of antibody rise from 1.6×108 L/mol to 6.9×108L/mol. With the continuous increase of the immune times the affinity came to mature and reached to 7.2×108 L/mol after the third immunity. Comparing affinity changes of continuous stimulation with it of interval immunity, we found out that the memory cells existing in body were those offspring of cells which could secrete higher affinity antibodies, and their special affinity was always maintained at a high level. At the same time, although the gene of B cells receptor did not mutate, their affinity to antigen became higher with the increase of immune times. Compared with the first immunity, the relative affinity constant of BCR has a five times enhancement after the third immunity. This phenomenon showed that there was a continuously screening process for memorial B cell in vivo. We analyzed the affinity change of different antigen determinant by capillary electrophoresis technology. Through comparing the affinity changes of different antibodies we assayed the physical characteristics of dominant antigen determinant. By analyzing affinity mature contribution of linear and solid antigenic determinant to antibodies, we can conclude that solid antigen determinant has a stronger competition ability in the process of immunity. The level of antibody affinity of linear determinant in all the determinants decrease from 75% in the first immunity to 69% in the fourth immunity. Our research will provide some of the theoretic reference for reaction mechanism of vaccines and antibody. At the same time it is useful for the design of modern vaccine based on antigen determinants.