Figure 2.
Immunodetection of kynurenine pathway enzymes and products in human neurons and brain. A, B, Cultures of human primary neurons (A) and of SK-N-SH cells (B) were immunostained for the enzymes IDO, TDO, KYNU, KAT-II, KMO, QPRT, and ACMSD, as well as for QUIN and MAP2 as indicated. C, Control preparations of cultures of human primary neurons: irrelevant IgG and nonimmune rabbit serum staining of human primary neurons. D, Human hippocampal sections were also immunostained for IDO, KMO, KYNU, ACMSD, TDO, KAT-II, and QUIN as indicated. Neuronal labeling for all markers was predominantly cytosolic, although occasional staining of proximal processes was seen (e.g., for KMO). Neurons of the hilus (CA4) were the most consistently labeled. Non-neuronal cells were also labeled. Punctate/vesicular labeling of probable microglial cells was widespread in all areas of cortex and hippocampus. QUIN labeling was distinctly granular, as shown in the pyramidal cells of CA1 (D).