INCREASED QUINOLINATE IMMUNOREACTIVITY IN THE PERIPHERAL-BLOOD MONOCYTES MACROPHAGES FROM SIV-INFECTED MONKEYS/

Quinolinate (QUIN), a metabolite in the kynurenine pathway of tryptoph an degradation and a neurotoxin that is thought to act through the NMD A receptor system, was localized in cultured peripheral blood monocyte s/macrophages from SIV-infected monkeys using a recently developed imm unohistochemical method. Significant increases in QUIN immunoreactive (IR) cells were detected in all five SIV-infected monkeys examined. Mu ltinucleated giant cells, a hallmark of lentiviral infection, were vis ible in selected samples. Treatment with the QUIN precursors, tryptoph an and kynurenine, increased the number of QUIN-IR cells in both the c ontrol and SIV-infected preparations, perhaps by a mass action mechani sm. We hypothesize that in SIV-infected monkeys, infiltrating monocyte s/macrophages contribute to the high level of brain QUIN and associate d neuropathology.