BRAIN-REACTIVE ANTIBODIES AND BEHAVIOR OF AUTOIMMUNE MRL-LPR MICE

The hypothesis that brain-reactive autoantibodies (BRA) impair behavio r was examined in MRL-lpr mice, which develop spontaneous autoimmune d isease. Circulating BRA were measured as in vitro serum reactivity to Neuro-2A neuroblastoma cell line, and behavioral competence was assess ed in activity monitors, open field, beam walking, and Morris water ma ze task. Mice with BRA in serum (BRA positive) exhibited slower sponta neous locomotion in a novel environment, shorter grooming episodes, an d less exploration of the open field centre when compared to age-match ed 7-11-week-old BRA-negative cagemates. Moreover, when initially expo sed to the large swimming pool, BRA-positive mice showed increased swi mming along the wall, but had no difficulty in learning the water maze task or in traversing a narrow beam. Brain-reactive autoantibodies ti tre and behavioral measures were not correlated, suggesting that the c oncentration of serum BRA is not reflective of the magnitude of behavi oral impairment. Nevertheless, the present study suggests that the pre sence of circulating BRA is associated with impaired exploration and/o r enhanced emotional reactivity in MRL-lpr mice. It also supports the hypothesis of a pathogenic role of BRA in various mental disorders.