Table 1.

Immunogenicity of CEA_694–702 and altered peptide ligands

Peptide	In vitro expansion method	Number of significant expansionsc	Number of cultures tested
CEA694–702WT	Microculturea	0	4
	DC basedb	0	5
CEA694–702L2	Microculture	3	4
	DC based	2	5
CEA694–702V9	Microculture	0	4
	DC based	1	5
CEA694–702L2V9	Microculture	3	4
	DC based	2	5

All experiments were performed by in vitro stimulation of PBMCs from nine HLA-A*0201 positive healthy donors with the indicated peptides

^aIn vitro stimulation was carried out in multiple parallel PBMC microcultures as described in Materials and methods

^bIn vitro stimulation was carried out by co-culture of purified CD8⁺ T-cells and autologous peptide-pulsed DCs and peptide-pulsed T2-cells at a ratio of 5:1

^cAfter 10 days of microculture or three rounds of in vitro stimulation (DC based), cells were labeled with anti-CD8 and A2/CEA peptide multimers. A culture was considered as positive when the number of CD8 A2/CEA peptide multimer cells was higher than 0.1% of CD8⁺ T-cells