OPTIMIZATION OF THE INTESTINAL LAVAGE PROCEDURE FOR DETERMINATION OF INTESTINAL IMMUNE-RESPONSES

Optimal conditions to process, concentrate and store intestinal lavage fluid were studied in samples collected from volunteers before and af ter oral immunization with a prototype vaccine against enterotoxigenic Escherichia coli (ETEC) diarrhoea. Total IgA and specific IgA antibod y titres against enterotoxin and colonization factor antigen were dete rmined in 22 lavage samples which were either enzyme-inhibited or heat -inactivated and then subjected to different long-term storage conditi ons. Samples were analysed within I month of collection and also after 3, 6 and 24 months of storage, Total IgA concentrations and specific IgA antibody levels were higher in lavage samples treated with enzyme inhibitors (soybean trypsin inhibitor and phenylmethylsulfonyl fluorid e) than in those heat-inactivated. Similarily, concentration of the la vage fluid by freeze-drying,cns superior to concentration against poly ethylene glycol, Specific antibody titres remained elevated after stor age for at least 6 months but declined after 2 years in frozen compare d with freeze-dried samples.