Abstract 3806: Stimulation of anti-leukemia immune response by a rice protein prolamin

Abstract

Abstract Rice (Oryza sativa), an important cereal as a staple food worldwide, has been demonstrated that its water extracts benefit anti-leukaemia immunity. The present study isolated and characterized the active rice proteins and assessed the anti-leukemia response via in vitro and ex vivo experiments. Proteomic analysis identified various protein spots known with functions involving metabolism-related, transport, storage, antioxidation, development, and disease resistance proteins. Among these, storage proteins were the most abundant. To avoid masking the other relatively scanty rice storage proteins, albumin, globulin, glutelin and prolamin were separated and quantified. Prolamin-prepared conditioned medium of human mononuclear cells (MNC-CM) showed the greatest inhibition of human leukaemia U937 cell growth. Prolamin enhanced MNC to secrete tumor necrosis factor-α and prolamin-prepared MNC-CM induced U937 cells toward monocyte differentiation, not only by morphological observation, but also by NBT-reduction test. Neutralization of prolamin by polyclonal antibody attenuated its activity. Prolamin has greater activity than wheat gluten (glutenin and gliadin), which can cause celiac disease (CD). Additionally, rice proteins were undetectable by wheat gliadin-specific antibody, suggesting that rice may be an ideal candidate of food substitute in CD patients. In conclusion, rice prolamin is effective in activating human anti-leukaemia immunity and may not induce unwanted inflammatory diseases. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3806.