APPARENT FUNCTIONALITY BUT IMPRACTICAL QUANTIFICATION OF NEUROTENSIN RECEPTORS ON HUMAN PERIPHERAL LYMPHOCYTES

Neurotensin (NT), a neuromodulator, is also thought to play an immunom odulatory role. We sought to confirm the effects of NT on proliferatio n in human peripheral blood lymphocytes (PBLs; n = 10), to characteriz e the binding properties of the NT receptor using Scatchard analysis, and to measure NT receptors using blood volumes (50 ml) applicable to clinical investigation. Incubation of phytohemagglutinin-stimulated PB Ls with NT (10(-10) to 10(-13) M) in the presence of 0.07% normal huma n serum (72 h at 37 degrees C) significantly enhanced proliferation (p < 0.001), which is consistent with PBLs possessing functional NT rece ptors. However, the various experimental conditions tested constantly yielded low specific NT binding to human PBLs, and hence Scatchard ana lysis was impossible for 50-ml blood samples. Our data confirm the exi stence of a link between NT and the immune system and support a physio logical significance for this link. However, measurement of NT recepto r binding in readily available cells proved unsuitable for clinical in vestigation.