CELLS TREATED WITH TAP-2 ANTISENSE OLIGONUCLEOTIDES ARE POTENT ANTIGEN-PRESENTING CELLS IN-VITRO AND IN-VIVO

Treatment of RMA and EL4 cells or freshly isolated splenocytes with an tisense (AS) oligonucleotides directed against the TAP-2 gene recreate s the phenotype seen in cells that are genetically deficient in TAP fu nction, Cells incubated with AS oligonucleotides exhibit reduced MHC c lass I expression on the cell surface, which can be increased by incub ating the oligonucleotide-treated cells at 28 degrees C or by adding M HC haplotype-matched peptides to the culture medium, RMA cells or sple nocytes treated with AS oligonucleotides and incubated with peptide we re highly effective in generating primary CTL responses in vitro. The bulk of the AS oligonucleotide-responsive and CTL-inducing cells resid ed in the adherent fraction of splenocytes, Moreover, TAP-2 AS oligonu cleotide-treated adherent splenocytes pulsed with OVA peptide elicited potent OVA-specific CTL responses in vivo and provided effective prot ection from challenge with tumor cells expressing the corresponding Ag , AS oligonucleotide technology provides a simple approach to develop broadly applicable methods for generating potent APC to study TAP func tion in normal cells and to identify other gene products involved in M HC class I presentation.