Evidence of immunosuppression in the genetically epilepsy-prone rat

Immune system function was examined in the genetically epilepsy prone (GEPR-9) rat and non-epileptic Sprague-Dawley control rats. Significant decreases in direct and indirect plaque-forming cell responses were observed in GEPR-9 rats immunized with sheep erythrocytes. Serum levels of IgM were also decreased in non-immunized GEPR-9 rats, providing additional evidence of immunosuppression. However, total serum levels of IgG were three-fold greater in GEPR-9 rats compared to control. These results suggest that the nature of the immune system deficit in the GEPR-9 is complex and may involve an active T-cell population stimulating an overproduction of IgG leading to a diminished capacity to respond to new antigen challenges. This immunological defect may underlie the enhanced susceptibility of GEPR-9 rats to infectious agents. The specific cause of this immune dysfunction is not known. Possible etiological factors include a breakdown in the communication between cells within the immune system or an alteration of neuroendocrine modulation of immune responses.