IL-4 IS ESSENTIAL FOR THE SYSTEMIC TRANSFER OF DELAYED-HYPERSENSITIVITY BY T-CELL LINES - ROLE OF GAMMA DELTA CELLS/

Hapten (trinitrophenyl)-specific T cell lines were obtained by repeate d stimulation of lymph node cells from immune mice with Ag in vitro. T hese T cell lines show phenotypic properties and a pattern of cytokine production typical of Th1 cells and consisted of more than 90% V beta 8.2(+) T lymphocytes and 6 to 9% gamma/delta(+) T lymphocytes. The li nes mediate a local passive transfer of DTH when injected al the site of Ag challenge but fail to mediate a systemic passive transfer of DTH when injected i.v. However, a successful systemic passive transfer of DTH was observed when IL-4 was given to recipient mice together with the T cell lines or when the T cell lines were incubated in vitro with IL-4. IL-4 enables systemic, specific passive transfer of DTH at a do se of 10 pg/ml in vitro and at a dose of 10 pg/mouse in vivo; it is ef fective when injected 4 h before cell transfer but not when given 1 to 5 days earlier. Cytofluorimetric analysis shows that the gamma/delta( +) cells and not the V beta 8.2(+) cells of the line express IL-4R and a good systemic transfer of DTH is observed when gamma/delta(+) cells are incubated in vitro with IL-4 and then injected together with V be ta 8.2(+) cells into recipient mice. In contrast, injection of V beta 8.2(+) cells treated with IL-4 together with gamma/delta(+) cells fail s to transfer DTH. Overall, the present results show that IL-4 is an i mportant mediator in the DTH reaction and that gamma/delta(+) cells ar e one of the targets of its action.