Transport of proteins through the membranes of the adult gastro-intestinal tract — a potential for drug delivery?

Relative Importance of Phytohemagglutinin (Lectin) and Trypsin-Chymotrypsin Inhibitor on Bean (Phaseolus vulgaris L) Protein Absorption and Utilization by the Rat.

“…The physiological and nutritional consequences of phytohemagglutinin binding to small intestine enterocytes have been demonstrated at intestinal and systemic levels. At intestinal levels, the main observed effects have been (a) degradation of microvilli (38); (b) changes in intestinal permeability (35); (c) cell absorption of intact active phytohemagglutinin (40); and (d) faster renewal of intestinal cells and cell hypertrophy (41).…”

Enterally but Not Parenterally Administered <i>Phaseolus vulgaris </i>Lectin Induces Growth and Precocious Maturation of the Gut in Suckling Rats

“…10% of the enteral dosage, was administered parenterally. This was to examine the claim that the systemic effects observed after enteral exposure were due in part to the 5-10% of the ingested PHA that may reach the general circulation, as has been observed in adult rats [10,11] . An immunohistochemical study was also conducted to investigate the site of PHA binding and localization after enteral versus parenteral administration.…”

Intestinal Receptor Targeting for Peptide Delivery: an expert‘s Personal Perspective on Reasons for Failure and New Opportunities

“…At the time when this process was init ially described, it was not the accepted paradigm for oral vaccination, as it was generally thought that uptake of intact proteins in the gut occurred via nonspecific antigensampling activity of the intestinal M cells, which promoted uptake of these drugladen particles from the intes tine [59][60][61]. It was subsequently shown by Gabor, RussellJones and others [51,52-55, [62][63][64][65][66] that effec tive oral immunization could be achieved using proteins that possessed lectinlike binding activ ity for the glycolipids and glycoproteins resident on the luminal membrane of the enterocyte [67,68]. The specificity of this phenomenon was demon strated when the specific sugar molecule to which the lectins bound was cofed with the lectin and a greatly reduced immune response was elicited to the lectin [52,55,67].…”