Influence of the intensity, level and phase of spinal cord injury on the proliferation of T cells and T-cell-dependent antibody reactions in rats

Study design: Three independent experiments in a rat model of contusive spinal cord (SC) injury were performed. Two studied the alterations induced by SC injury on some immunological aspects of the T-cell response. The third one evaluated the motor recovery of rats with low-thoracic injuries. Objective: To examine the effect of level, intensity and phase of SC injury on T-cell proliferation and T-cell-dependent antibody response. Setting: Neuroimmunology Department, UIMEN, IMSS-CAMINA Research Center. Methods: Lymphocyte proliferation and hemagglutination assays were performed. Animals were injured either moderately or severely at T1 or T12 SC segments. Analysis of peripheral T-cell proliferation in response to mitogens and to myelin basic protein (MBP), as well as of antibody production against a T-dependent antigen, was performed at acute, subacute and chronic phases. Results: A significant decrease of both response to mitogens and antibody production was found especially during the acute phase and in animals with severe and high (T1)-level injury. Animals with low (T12) and moderate contusions recovered to control levels at the chronic phase. An autoimmune reaction against MBP was observed only in animals with severe contusion at low level. Conclusions: The intensity, level and phase of SC injury differentially alter the function of T cells. These results will allow a better interpretation of studies directed to elucidate the role of T lymphocytes in various processes developed after SC injury. Sponsorship: CONACYT, grant No. I29995-M.