HLA Class II Defects in Burkitt Lymphoma: Bryostatin-1-Induced 17 kDa Protein Restores CD4+ T-Cell Recognition
Figure 6
Treatment of BL with bryostatin-1 causes upregulation of a 17 kDa immunostimulatory protein. (a) Acid eluate from Nalm-6.DR4, Nalm-6.DR4 treated for 24 h with 40 nM bryostatin-1 and 6.16.DR4.DM were collected, and subjected to SDS-PAGE, followed by coomassie blue staining. Gel banding patterns revealed upregulation of a 17 kDa protein in bryostatin-treated Nalm-6.DR4 that is expressed at low levels in untreated Nalm-6.DR4 but highly expressed in 6.16.DR4.DM. (b) Acid eluate from 6.16.DR4.DM was separated on a large, non-reducing gel, the band corresponding to 17 kDa was excised, and the protein was extracted by sonication in PBS on ice. Ramos.DR4 cells were then incubated in PBS or 17 kDa gel extract with synthetic peptide. Cells were then washed and co-cultured with the T-cell hybridoma line 17.9. Supernatant from the co-culture was assayed by ELISA to determine IL-2 levels as a measure of T-cell stimulation. Results show that IL-2 stimulation is significantly increased in Ramos.DR4 cells incubated with peptide in the presence of the 17 kDa gel extract. *indicates .
