Table IV.

I-A^g7 Forms Long-lived Complexes with Certain Peptides

Peptide		Dissociation time (t1/2)
		pH 5.0		pH 7.4
Murine serum albumin (560–574)		>72 h		>72 h
Murine transferrin (55–68)		∼45 h		>72 h
Human HSP60 (441–460)		∼14 h		∼25 h
Human GAD65 (249–263)		not detectable		not detectable
HSV-2 VP16 (430–444)		not detectable		not detectable
Murine CLIP		not detectable		∼1 h
Murine CLIP 98D analogue		∼23 h		∼70 h

The dissociation time (t_1/2) of a panel of peptides was examined as described in Fig. 6. Several peptides formed long-lived complexes with I-A^g7, particularly at a neutral pH. The peptides included the naturally processed peptides from serum albumin and transferrin, as well as a peptide from human HSP60 (res. 441–460) that has been identified as a T cell epitope in NOD mice. The dissociation of the CLIP peptide at pH 5.0 was very rapid and a half-life could not be determined. These data demonstrate that I-A^g7–peptide complexes can be long lived, even though I-A^g7–peptide complexes are not SDS resistant.