Table II.

IFN-α/β Act Directly on T Cells

Additions to culture		Percentage indicated of cells surviving in mixed cultures
		Wild-type				IFNR-α/β–deficient
		CD4		CD8		CD4		CD8
None		43.6 ± 1.8		33.5 ± 0.4		45.9 ± 2.4		21.5 ± 0.9
IFN-α/β		49.7 ± 0.6		54.4 ± 0.8		43.9 ± 0.4		22.4 ± 0.6

IFN-α/βR–deficient mice and mice of their closely related wild-type strain, 129/SvEv, were injected intravenously with 150 μg SEB. 2 d later T cells were isolated from the lymph nodes of the mice. The cells from the IFN-α/βR–deficient mice were staIned with CFSE as described in Materials and Methods. Mixtures containing equal numbers of cells from each type of mouse were cultured for 28 h in the absence or presence of 3,333 U/ml IFN-α/β and then stained with PE–labeled anti-CD4 or anti-CD8 and biotinylated anti-Vβ8 followed by CySA. Results shown are the mean ± SE of data from three identical cultures.