Harriet Link

Protection by Milk Immunoglobulin Concentrate against Oral Challenge with Enterotoxigenic Escherichia coli

Enterotoxigenic Escherichia coli is a common cause of travelers diarrhea. Prophylaxis against travelers diarrhea has been associated with side effects from bismuth subsalicylate and the development of resistance to antimicrobial agents. We undertook a double-blind controlled trial in which a bovine milk immunoglobulin concentrate with high titers of antibodies against enterotoxigenic E. coli was used as prophylaxis against E. coli challenge in volunteers. Lyophilized milk immunoglobulins were prepared from the colostrum of cows immunized with several enterotoxigenic E. coli serotypes and fimbria types, E. coli heat-labile enterotoxin, and cholera toxin. As a control, an immunoglobulin concentrate with no anti-E. coli activity was prepared. Ten volunteers received buffered immunoglobulin concentrate against enterotoxigenic E. coli, and 10 received the control immunoglobulin concentrate, dissolved in water, three times a day. No side effects were observed. On the third day of immunoglobulin prophylaxis, the volunteers were given 10(9) colony-forming units of enterotoxigenic E. coli H10407 (O78:H11). This strain produces colonization factor antigen I and heat-labile and heat-stable enterotoxins. None of the 10 volunteers receiving the immunoglobulin concentrate against E. coli had diarrhea, but 9 of the 10 controls did (P less than 0.0001). All volunteers excreted E. coli H10407. We conclude from these preliminary results that milk immunoglobulin concentrate may be an effective prophylaxis against travelers diarrhea.

Immunomodulation of the Gnotobiotic Mouse Through Colonization with Lactic Acid Bacteria

The contribution of the intestinal microflora and microbial antigens to the development of the mucosal immune system has been recognized. The germ-free rodent is the main model to study the influence of the microflora in theontogeny of this system. The aim of this work was to detect if different strains of lactic acid bacteria or their soluble products could produce different patterns of immunomodulation in the host. Some bacteriological and immunological parameters were chosen: bacterial colonization, bacterial translocation, white blood cell counts, serum immunoglobulins, and the intraepithelial lymphocyte (IEL) population of the gut.