Table 1.

Cytokine-secretion pattern in Mycobacterium tuberculosis 19-kDa reactive CD8⁺ T-cell lines

	T2 alone			T2+ control			T2+ VLTDGNPPEV
Lines (no.)	GM-CSF	IL-4	IFN-γ	GM-CSF	IL-4	IFN-γ	GM-CSF	IL-4	IFN-γ
1	3	0	100	0	0	100	400	41	100
2	7	0	400	6	0	380	400	38	400
3	6	0	100	7	0	100	8	63	130
4	10	0	300	3	0	330	9	0	280
5	3	0	330	2	0	350	3	0	300
6	3	0	400	3	0	400	10	0	800

Cytokine release is expressed as pg/ml/24 hr.CD8⁺ T cells were repetitively stimulated with dendritic cells (DCs) loaded with the immunodominant peptide from the Mycobacterium tuberculosis 19-kDa peptide VLTDGNPPEV and tested for recognition of the nominal target epitope. T2 cells served as the surrogate recipient cell line. Controls were T2 cells alone, or T2 cells pulsed with an irrelevant human leucocyte antigen (HLA)-A2 binding peptide (control) from the melanoma-associated antigen gp100 (KTWGQYWQV). CD8⁺ T-cell lines secreted interferon-γ (IFN-γ) to T2 cells alone, or to those pulsed with the control peptide. CD8⁺ T-cell lines from individuals 1 and 2 secreted significant amounts of interleukin-4 (IL-4) or granulocyte–macrophage colony-stimulating factor (GM-CSF) in response to the target antigen, as compared to T2 cells alone or T2 cells pulsed with an irrelevant control peptide. Note that only CD8⁺ T cells obtained from individual 6 secreted significant levels of interferon-γ (IFN-γ) as compared to the control targets. T cells from individual 3 secreted IL-4 and low amounts of IFN-γ as compared to control targets. Data are representative of three experiments. No cytotoxic response was observed in a 4-hr standard

⁵¹Cr-release assay (data not shown).

Values shown in bold are significant versus controls.