Studies in passive transfer. 4. Rectal absorption of the antigen (egg white)

Abstract

N VIEW of the interest in allergic as well as physiologic phenomena, the question of colonic absorption is important. This report presents data obtained in a study of that question. The products of protein digestion in vitro differ from the original protein by being slightly diffusible. For some time it was assumed that only diffusible protein was absorbed and hence that peptonization was essential. Schloss and Worthen,l however, demonstrated by precipitin and anaphylactic tests, that foreign protein might be absorbed. in an undigested or partially digested state. This has been more recently confirmed by Walzer2 by application of the local passive transfer phenomenon described by Prausnitz and Ktistner.3 Walzer showed that, in adults, oral administration of the antigen gave results quite comparable with those obtained by injection in the local sensitized skin areas. In a previous study4 me have reported similar results in new’born infants. There has remained, however, the question as to the site of this absorption in the intestinal tract. The opinion in many textbooks is that. absorption takes place above the cecum and that only water a.nd crystalloids are absorbed from the large bowel. The contrary evidence of Voit? has apparently been overlooked. Following rectal a.dministration of egg white and salt solution, they found an increase in urinary nitrogen. Since it was, known that practically no peptonization took place in the colon and since the effect of enzymes could be ruled out, absorption probably accounted for their findings. Egg white represents a nonassimilable type of protein in colztrast with its acid albumin fraction. Introduced in the blood stream the former substance is excreted by the kidney. Schloss and Worthenl demonstrated the presenee of egg white in the urine following oral administration. They emphasized the greater absorption from upset or abnormal intestinal t.racts. Colonic absorption is suggested from their findings since with increased peristalsis the chance of absorption from the upper intestinal tract is 1es.s. Yet it has been shown by previous passive transfer studies4 that the majority of healthy yoang infants will absorb egg white antigen after oral administration. The f olloming experiments were designed to see if application of local passive trans-