CROSS-TALK BETWEEN V-BETA-8(-DELTA(+) T-LYMPHOCYTES IN CONTACT SENSITIVITY() AND GAMMA)

We have previously reported that T lymphocytes proliferating in vitro to the hapten trinitrochlorobenzene (TNCB) exhibit a very restricted V beta gene usage and response to TNCB is limited to T-cell receptors ( TCR) composed of V beta 8.2. in combination with V alpha 3.2, V alpha 8 and V alpha 10. This paper investigates the role played by T lymphoc ytes expressing the V beta 8.3 gene segment in the contact sensitivity (CS) reaction to TNCB in the intact mouse and in its passive transfer into naive recipient mice. Mice injected with monoclonal antibodies t o V beta 8 are unable to develop CS upon immunization with TNCB and 4- day TNCB-immune lymph node cells from mice that had been depleted in v ivo or in vitro of V beta 8(+) T lymphocytes fail to transfer CS, Howe ver, when separated V beta 8(+) and V beta 8(-) cells were used for pa ssive transfer, it was found that V beta 8(+) T lymphocytes failed to transfer CS when given alone to recipient mice and a V beta 8(-) popul ation was absolutely required. Further analysis revealed that within t he V beta 8(-) population. T lymphocytes expressing the gamma delta TC R were fundamental to allow transfer of the CS reaction. These gamma d elta cells were found to be antigen non-specific, genetically unrestri cted and to rearrange the V gamma 3 gene segment. This indicates that transfer of the CS reaction requires cross-talk between V beta 8(+) an d gamma delta(+) T lymphocytes, thus confirming our previous results o btained using TNCB-specific T-cell lines. Time-course experiments show ed that V beta 8(+) lymphocytes taken 4-24 days after immunization wit h TNCB were able to proliferate and produce interleukin-2 (IL-2) in re sponse to the specific antigen in vitro. Similar time-course experimen ts were then undertaken using the passive transfer of the CS reaction system. The results obtained confirm that TNCB-specific V beta 8(+) T lymphocytes are present in the lymph nodes of immunized mice from day 4 to day 24, and reveal that gamma delta(+) T lymphocytes are active f or a very short period of time, i.e. days 4 and 5 after immunization. In fact, TNCB-specific V beta 8(+) cells are able to transfer CS when taken 4-24 days after immunization, providing the accompanying V beta 8(-) or gamma delta(+) T lymphocytes are obtained 4 days after immuniz ation. In contrast, injection of V beta 8(+) T lymphocytes together wi th V beta 8(-) or gamma delta(+) T lymphocytes that had been taken 2 o r 6 days after immunization, failed to transfer significant CS into re cipient mice, Taken together, our results confirm that cross-talk betw een V beta 8(+) and gamma delta(+) T lymphocytes is necessary for full development of the CS reaction and may explain why the CS reaction in the intact mouse lasts up to 21 days after immunization while the abi lity of immune lymph node cells to transfer CS is limited to days 4 an d 5 after immunization.