Mg. Espey et al., TEMPORAL AND SPATIAL CHANGES OF QUINOLINIC ACID IMMUNOREACTIVITY IN THE IMMUNE-SYSTEM OF LIPOPOLYSACCHARIDE-STIMULATED MICE, Journal of leukocyte biology, 57(2), 1995, pp. 199-206
Quinolinic acid (Quin), a metabolite of tryptophan, is a neurotoxin th
at has been implicated in a variety of neuropathologic disorders that
have immune components. The goal of this study was to characterize the
changes in the cellular localization of Quin immunoreactivity in a pa
radigm of immune stimulation with lipopolysaccharide (LPS) in vivo to
provide a basis for further studies on the physiological role of Quin
in the immune system. Intraperitoneal LPS injection significantly incr
eased Quin immunoreactivity (IR) in lymphoid tissues within 24 h. Spat
ial changes in splenic Quin-IR demonstrated a shift from the periarter
ial lymphoid sheaths to the follicles before returning to control leve
ls by 72 h post-LPS. The strongly Quin-IR cells were tentatively ident
ified as interdigitating dendritic cells and macrophages. Only minimal
Quin-IR was detected in liver and lung, even under conditions of LPS
stimulation combined with tryptophan loading. These data emphasize the
temporally and spatially specific nature of Quin-IR changes in lympho
id tissues under conditions of immune stimulation and raise the possib
ility that Quin may have an immunomodulatory function.