Delayed superantigenic stimulation restores deletion and anergy of adoptively transferred cells.

(A) Deletion: SCID mice reconstituted with BALB/c cells were observed (control, n = 5) or were injected with SEB immediately (day 0 SEB, n = 25), 2 (day 2 SEB, n = 2), or 9 (day 9 SEB, n = 5) days after adoptive transfer. Ten days after SEB stimulation (or 10 days after transfer, control), the percentages of peripheral lymph node CD4⁺Vβ8⁺ T cells were determined by flow cytometry. Delayed SEB challenge restores the deletion of SEB responsive cells. The percentages of peripheral lymph node CD4⁺Vβ8⁺ T cells in BALB/c mice before (BALB, n = 4) and 10 days after (BALB + SEB, n = 19) injection of SEB are shown for comparison. The percentages plotted reflect absolute cell numbers (not shown), with means ± SE from n animals shown. Asterisk indicates statistically significant difference (P < .02) between control and adoptively transferred mice. (B) Anergy: The SEB-dependent proliferative capacity of transferred CD4⁺Vβ8⁺ T cells was determined after delayed SEB challenge. Reconstituted SCID mice were initially challenged with SEB 9 days after adoptive transfer and were then rechallenged 10 days later, and the total numbers of spleen and peripheral lymph node CD4⁺Vβ8⁺ T cells were determined by flow cytometry and manual counting 48 hours later. The total number of CD4⁺Vβ8⁺ T cells was determined in a similar manner in mice that had been reconstituted for 21 days, but had received only a single injection of SEB 12 days before, and the ratio of these numbers was used to calculate a proliferation index representing the ability of SEB-stimulated T cells to proliferate in response to a second challenge with SEB (SEB rechallenge, n = 5). The proliferation index of CD4⁺Vβ8⁺ T cells in response to a primary stimulation with SEB after adoptive transfer was determined in a similar manner (1° SEB challenge, n = 3). Delayed SEB challenge restores SEB-dependent anergy (P < .02). The means ± SE from n animals are reported.