Partial inhibition of Theileria parva-infected T-cell proliferation by antisense IL2R alpha-chain RNA expression

Antisense RNA expression was used to assess the role of the interleukin 2 receptor (IL2R) alpha-chain in proliferation of T cells transformed by infection with the intracellular parasite Theileria parva. Two vectors were constructed, in which part of the bovine IL2R alpha-chain cDNA was inserted in either a sense or antisense orientation in the plasmid pHS1-CAT, which is expressed by induction of the human metallothionein IIA (hMT-IIA) with cadmium (Cd2+). A T. parva-infected T-cell line, TpM(803), known to express the IL2 and IL2R genes in a constitutive way, was permanently transfected with one of the two constructs, and the effect of antisense IL2R alpha-chain RNA expression upon proliferation of TpM(803) cells was tested. Antisense-transfected TpM(803) cells grew much more slowly than sense-transfected cells even in the absence of added Cd2+, but the addition of Cd2+ to the culture medium resulted in further inhibition. A strong reduction in IL2R alpha-chain mRNA was observed in antisense but not in sense-transfected cells. These observations confirm a role for the IL2R alpha-chain in proliferation of T. parva-infected TpM(803) cells.