EPITOPE SPECIFICITY OF ANTIBODIES RAISED AGAINST ENTEROTOXIGENIC ESCHERICHIA-COLI CFA I FIMBRIAE IN MICE IMMUNIZED WITH NAKED DNA/

The cfaB gene, coding for the CFA/I fimbrial adhesin of enterotoxigeni c Escherichia coli (ETEC), was cloned and expressed as a fusion peptid e with the glycoprotein D (go) from herpes simplex virus type I (HS) i n the pRE4 eukaryotic expression vector; resulting in the recombinant plasmid pRECFA. All BALB/c mice injected intramuscular ly (i.m.) with a single nose (100 mu g) of the purified plasmid developed antibodies against epitopes found on dissociated CFA/I subunits as well as other homologous ETEC fimbriae. Surface-exposed epitopes found on intact CFA /I fimbriae were also recognized by antibodies derived from DNA immuni zation, but they did not over-lap with those generated with purified C FA/I fimbriae. None of the sera raised in mice immunizated with pRECFA were able to agglutinate bacterial cells or-inhibit haemagglutination promoted by CFA/I bearing ETEC cells, These results show that pRECFA cart elicit CFA/I-specific antibodies, which may have different epitop e specificities and functional properties compared with those generate d with purified bacterial protein. (C) 1997 Published by Elsevier-Scie nce Ltd.