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Octapeptide but not nonapeptide from HIV-1 p24gag protein upregulates cell surface HLA-C expression
A Kozłowska1, W Gorczyca, Z Maćkiewicz
1Laboratory of Immunogenetics and Laboratory of Signalling Proteins, Ludwik Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wroclaw, Poland.
Objectives:
The HLA-Cw3 molecule has been reported to present peptides derived from HIV-1 p24gag protein to a cytotoxic T lymphocyte clone. We have shown previously that the synthetic octapeptide 145-152 derived from the p24gag sequence upregulated cell surface HLA-C expression on HLA-Cw*0303+ cells. Here, we examined the question of whether the nonapeptide 144-152 also exerts a similar effect.
Methods:
The HLA-Cw*0303+ B-LCL PAJ and control HLA-Cw3-negative cells B-LCL HAJ and T-LCL 500/C9 were used. HLA expression on peptide-pulsed and non-pulsed cells was evaluated using specific antibodies and flow cytofluorimetry. Binding of dansylated peptides onto different cell lines was measured spectrofluorimetrically.
Results:
The HIV-1 p24gag octapeptide upregulated cell surface HLA-C on PAJ (Cw*0303+) cells, whereas the nonapeptide did not. HLA-A2 expression was not affected by these peptides. Specificity of the effect of octapeptide was confirmed by the lack of HLA-C upregulation on HLA-Cw3- cells and by lower binding of dansylated peptide to the HLA-Cw3- cells HAJ and 500/C9.
Conclusions:
The above results indicate that HLA-Cw*0303 preferentially binds the octapeptide rather than the nonapeptide derived from HIV-1 p24gag protein.