A. APLs with alterations flanking the core region (aa 161, 162 and 172); B. APLs with changes within potential MHC contacts (aa 163, 166, 168 and 171); and, C. APLs with residue substitutions at putative TCR contact sites (aa 164, 167, 169 and 170). Proliferative responses of naïve LACK-BV4 TCR transgenic splenocytes to the w/t LACK 161–175 peptide (empty circles: ○), or various analogs (filled symbols) for all left panels. The frequency of cytokine producing cells among naïve LACK-BV4 transgenic cells in response to w/t LACK or analogs by ELISA spot (all right panels). Bars in white represent IL-4 spots per 106 splenocytes, bars in black represent IFNγ spots per 106 splenocytes (the standard deviation of duplicate wells was less than 10%.). One representative of 3 experiments is depicted.