Influence of acute and repeated interleukin-2 administration on spatial learning, locomotor activity, exploratory behaviors, and anxiety.

Interleukin-2 (IL-2), released from activated T cells, influences central neurochemical functioning, and IL-2 immunotherapy in cancer patients may provoke neuropsychiatric and cognitive disturbances. In this study, acute, systemic IL-2 did not influence Morris water-maze performance in mice. In contrast, chronic IL-2 impaired performance when the position of the escape platform varied over days but was without effect when the platform position was fixed. These effects could not be attributed to illness, because IL-1beta, which induces marked malaise, did not influence water-maze performance. Chronic IL-2 produced modest reductions in exploration and approach to a novel stimulus, effects not seen after acute treatment, but did not influence spontaneous alternation performance or behavior in an elevated plus-maze test. Thus, repeated IL-2 may influence spatial working memory without affecting habituation/ attentional processes or anxiety.