A method to screen T lymphocyte epitopes after oral immunisation of humans: application to cholera toxin B subunit.

The response to oral immunisation of humans with classical biotype cholera toxin B subunit was studied to identify immunodominant T lymphocyte determinants. The in vitro proliferative response to pools of 12-mer peptides and larger peptides used individually was analysed by a novel statistical approach, and identified an immunodominant region in residues 70-79 in immunised subjects, when either pools or individual peptides were employed. In contrast, a patient infected with El Tor biotype had a dominant response to residues 40-60. The statistical software employed in this study may enable efficient screening of antigens for immunodominant T lymphocyte determinants when blood precursor frequencies are low following immunisation, and may therefore be of special relevance to mucosal vaccines.