Identification and Characterization of Phytohemagglutinins from White Kidney Beans (Phaseolus vulgaris L., var. Beldia) in the Rat Small Intestine

Although kidney bean (Phaseolus vulgaris L.) lectin toxicity is widely known, its effects in the gastrointestinal tract require further study. This investigation aimed to identify and characterize phytohemagglutinins (PHAs) in the small intestine and sera of rats following oral challenge with ground white beans. Twenty young, adult male rats were divided randomly into two groups of 10 animals each. The control group underwent gavage with a suspension of 300 mg of rodent pellet flour. The experimental group was administered a 300 mg Beldia bean flour suspension (BBFS). After 10 days of daily treatment, jejunal rinse liquid (JRL) and ileum rinse liquid and secretions, as well as sera, were collected. All biological fluids were screened for lectin reactivity using competitive inhibition ELISA, Ouchterlony double immunodiffusion, and immunoelectrophoresis techniques. The results revealed the presence of immunogenic intraluminal PHAs 3–4 h after the oral intake of the BBFS in the JRLs as well as in the jejunal and ileal secretions; however, no PHA was detectable in the rat sera. Ingestion of raw Beldia beans may lead to interaction between PHAs and the mucosa of the small intestine, potentially resulting in an inflammatory response.