TABLE 3.

Comparison of HTLV-I-infected T-cell clones, HTLV-I-transformed T-cell lines, and peripheral blood mononuclear cells from HTLV-I-infected individuals^a

Characteristic	Uninfected T cells, T-cell clones, or PBMCsb	HTLV-I-infected T-cell clones	HTLV-I-transformed T-cell lines	PBMCs from HTLV-I-infected individuals
IL-2-independent growth	−	±c	+	−
Spontaneous proliferationd	−	+	+	+
Inhibition of spontaneous proliferation by:
Rapamycin	NAe	+	−	+
FK506	NA	−	−	+
CsA	NA	−	−	+
TGF-β	NA	−	−	+
IFN-β	NA	−	±f	+
Anti-IL-2Rα MAbg	NA	−	−	+
Inhibition of CD3/TCR-mediated proliferation by:
Rapamycin	+	+	NA	+
FK506	+	+	NA	+
CsA	+	+	NA	+
TGF-β	+	+	NA	+
IFN-β	+	+	NA	+
Anti-IL-2Rα MAb	+	+	−	+

^aBased on references 119, 124, 127, 270, and 288. 

^bPBMC, peripheral blood mononuclear cells. 

^cHTLV-I-infected T-cell clones require IL-2 for growth but may proliferate for a limited time in the absence of IL-2. 

^dSpontaneous proliferation of T-cell clones is measured by IL-2 independent [³H]thymidine incorporation 7 to 14 days after stimulation. Spontaneous proliferation of peripheral blood mononuclear cells from HTLV-I-infected individuals is measured by [³H]thymidine incorporation after 5 to 7 days in culture in the absence of exogenous growth factors. 

^eNA, not applicable. 

^fThe degree of inhibition of HTLV-I-infected T-cell lines by IFN-β depends on the T-cell line but is less than that of uninfected T-cell lines. 

^gMAb, monoclonal antibody.