The Effects Of Immunological Memory On Mouse Acquired Behavior

When organisms are stimulated by foreign bodies, the immune system identifies foreign antigens and elicit the immune response: B lymphocytes are converted into plasma cells to secrete immunoglobulins, while T lymphocytes activate, proliferate and differentiate into effector T cells, both involved in the process of recognizing and clearing foreign antigens. At the same time, a number of immunological memory cells will be produced, namely Tm and Bm cells. Memory lymphocytes do not carry out the effector functions directly, but activate, proliferate and differentiate into effector lymphocytes so quickly that the immune response is elicited efficiently and persists for long, after meeting the same antigen again. This characterizes the secondary immune response with short latency, rapid increase of antibody concentration, predominance of IgG, which contribute to more effective clearance of foreign antigens compared with the primary immune response. Immunological memory confers immune responses the memorial, efficient and specific characteristics, which is very similar to learning and memory activities of human brain.Learning and memory are essential brain functions for humans and animals to survive, and the avoidance behaviors of animals are acquired in the manner like the learning and memory activities of human. During the process of learning and memory, the increased synthesis of RNA proteins and polysaccharides in the brain concerns the expression of multiple genes. A large quantity of facts have demonstrated the process of learning and memory is closely related with the expression of immediate early genes (EEGs) in the brain, such as c-fos, while the high level expression of c-Fos can be observed during signal transduction when TCR (antigen recognition receptor) of T lymphocyte recognizes foreign antigens. In my experimets, mice were injectedintramuscularly with sheep red blood cell(SRBC) and normal saline(NS) respectively, and after the second injection they were divided into the experiment group( mice with immunological memory) and the control group (mice without immunological memory);then all the mice were trained by passive avoidance (step down method).The learning and memory performance (step down latency, Lsd),expression of c-Fos in hippocampus (immunohistochemical staining of mouse brain paraffin sections, SABC method), and induced expression of c-Fos in normal lymphocytes by sera were all compared between the two groups of mice. Meanwhile, the titers of specific antibodies of immunized mice were determined. The experiment results showed that: there is statistically significant difference (P<0.05) in learning and memory performance, expression of c-Fos in hippocampus between the two groups,i.e., the two items of experiment mice were higher than those of control mice. The expression of c-Fos in normal lymphocytes was strongly positive induced by sera from experiment mice. Correlation analysis did not support relationship between the titers of anti-SRBC antibody and results of immunohistochemical staining, or between the titers and learning and memory performance in statistics (P>0.05).The above results showed the mice with immunological memory (experiment group) were superior to those without immunological memory (control group) in the learning and memory performance, and establishment of immunological memory may increase the expression of c-Fos in mouse hippocampus, which might be related with serum c-Fos inducers capable of promoting the expression of c-fos gene in lymphocytes and hippocampus cells. Therefore it can be basically accepted that immune system not only is regulated by the nervous and the endocrine systems, but also has fairly obvious promotion to the learning and memory activities in brain. Since their correlation had no statistical significance, the exact mechanism on the molecular level should be further investigated. In conclusion,!.The learning and memory performance of mice with immunological memory were superior to the mice without immunological memory, which is first observ...