Immunodominant protein epitopes I. Induction of suppression to hen egg white lysozyme is obliterated by removal of the first three N‐terminal amino acids

The lack of response to hen egg white lysozyme (HEL) by C57BL (H-2b) mice has been demonstrated previously to be related to the induction of suppressor T (Ts) cells which recognize the amino terminal region of HEL. In this report, the nature of the protein determinant required for Ts cell induction is more precisely detailed using des-1,2,3-HEL (AP-HEL) prepared with an aminopeptidase purified from Aeromonas proteolytica . Remarkably, the removal of just these three amino acids obliterates the ability of HEL to induce Ts cells specific for HEL. Additionally, in contrast to HEL, AP-HEL is able to prime for an in vitro T cell proliferative response to either AP-HEL or HEL. Thus, removal of a very limited region of a protein antigen can drastically alter its immunogenic properties.