The sequences and profiles of peptides which bind to HLA-B*2705 splenocytes and peripheral blood cells were compared with those previously published from in vitro long-term cell cultures. B*2705 peptide profile analysed by solid-phase Edman degradation and 15 individual peptide sequences determined by LC-MS/MS were partially similar to those defined from in vitro long-term cell cultures. Arg at P2 was found in 11 of 15 sequenced peptides (73.3%). This value is lower in comparison with other published data. Two sequences were matching to unknown proteins, which displayed similarity with myosin. These are first data on peptide sequences isolated directly from HLA-B27 molecules without prior in vitro propagation of the cells.