Immunomodulatory activities of the somatostatin analogue BIM 23014c: effects on murine lymphocyte proliferation and natural killer activity.

We have examined the effect of somatostatin and its octapeptide analogue BIM 23014c on concanavalin A-induced lymphocyte proliferation and target-specific natural killer activity both in vitro and in vivo. Using Peyer's patches and spleen as a source of lymphocytes, we found that both peptides modulated immunity in a dose-dependent manner. Comparatively, there was no significant difference between the activity of somatostatin or BIM 23014c in the modulation of immunity. Proliferation, both in vitro and in vivo, was significantly inhibited by both peptides in each organ with a higher specificity towards the Peyer's patch lymphocytes. Natural killer activity was also inhibited in both organs in vivo and in vitro. Thus, not only did somatostatin and BIM 23014c have similar effects on proliferation and natural killer activity, but their effect was organ specific. Preliminary data suggest that BIM 23014c works via the same receptor as somatostatin, therefore intimating that these two peptides are both clinically and immunologically similar.