Antisense oligodeoxynucleotides as probes of T-lymphocyte gene function.

Conventional and thiophosphonate-derivatized oligonucleotides were employed to specifically regulate functional gene expression in murine T-cell hybridomas. For example, induction of apoptotic cell death following activation of T-cell hybridomas was examined using antisense oligonucleotides corresponding to several protooncogenes. We found that antisense oligodeoxynucleotides corresponding to c-myc inhibited both the characteristic DNA fragmentation and the loss of cell viability following activation without affecting production of lymphokines. Functional antisense oligonucleotides corresponding to c-fos had no effect in this system. These results demonstrate the use of antisense oligonucleotides to regulate function in T-cell hybridomas and provide valuable insights into the molecular bases of this biological phenomenon. Antisense oligonucleotides were also used to study another problem, the relation of T-cell-derived antigen-specific immunoregulatory factors to the T-cell receptor (TCR). Because the translation start of each TCR gene usually varies from one T cell to another, antisense oligonucleotides corresponding to the TCR V alpha or V beta of different cells were shown to act in a cell-specific manner. Furthermore, this method was used to demonstrate that a soluble antigen-specific regulatory activity produced by one of the T-cell lines depends on expression of the specific TCRa, an observation that has since been confirmed by gene transfer experiments. Expression of the CD3-TCR complex on the cell surface was also blocked by antisense oligonucleotides corresponding to CD3 gamma and CD3 zeta; however, neither these nor TCR V beta antisense oligonucleotides had any effect on production of the soluble regulatory activity.