Induced neuronal expression of class I major histocompatibility complex mRNA in acute and chronic inflammation models.

Studies have demonstrated neuronal expression of class I major histocompatibility complex (MHC) mRNA and protein in normal and developing brain and in response to injury or viral infection. We report neuronal expression of class I MHC mRNA in hypothalamic paraventricular nucleus (PVN) neurons in rats following systemic infection with Trypanosoma brucei brucei parasites (chronic) and in response to intravenous 1 mg/kg lipopolysaccharide administration (acute peripheral) and in striatal neurons following intrastriatal 5 microg lipopolysaccharide injection (acute central). These results demonstrate that neurons can be a source of immune signaling molecules and establish class I MHC as part of the neuronal component of immune responses.