ORAL-ADMINISTRATION OF POLYMERIC IMMUNOGLOBULIN-A PREVENTS COLONIZATION WITH VIBRIO-CHOLERAE IN NEONATAL MICE

A simple animal model was used to demonstrate passive protection by im munoglobulin A (IgA) against a mucosal pathogen, Vibrio cholerae. Oral administration of a monoclonal IgA directed against a lipopolysacchar ide component of the vibrio protected neonatal mice against oral chall enge, as measured by reduced intestinal colonization. A single dose of 0.1 mu g of polymeric monoclonal IgA given 1 h prior to challenge red uced the number of recoverable vibrios by at least 100-fold. An additi onal dose 3 h before challenge or 1 h after challenge did not enhance protection. A 10-fold-higher concentration of monomeric IgA was requir ed to achieve the same level of protection as that conferred by polyme ric IgA. Polymeric IgA digested with trypsin or human duodenal aspirat es to lower-molecular-weight fragments retained most of its ability to protect mice against challenge.