Natural killer-like function of activated T lymphocytes: Differential blocking effects of monoclonal antibodies specific for a 90-kDa clonotypic structure

Phorbol ester induces a differential effect on the effector function of human allospecific cytotoxic T lymphocyte and natural killer clones.

“…These data strongly suggest that PMA was able to inhibit the allospecific cytotoxicity and the T3+ NK-mediated cytotoxicity (data not shown), by modulating the T3-Ti complex expression at the cell membrane. Furthermore, the results indicate that most of the NK-activated cells in the bulk cultures were T3-and therefore were neither blocked by PMA or anti-T3 antibodies, suggesting that (i) the NK T-cell clones using the T3-Ti structures, as reported by Hercend et al (21), might represent a minority of NK-activated cells selected by the in vitro procedure used to expand them and (it) the cell surface Taken together, these data favor PMA's interference in cell-mediated cytotoxicity via the structures involved in specific antigen recognition-mainly, the T3-Ti complexwithout affecting the lytic mechanism per se. It should be pointed out that the loss of function induced by PMA was transitory and could be restored 5 days after PMA treatment.…”

Generation of monoclonal antibodies to a human natural killer clone. Characterization of two natural killer-associated antigens, NKH1A and NKH2, expressed on subsets of large granular lymphocytes.

“…JTlI was a clone derived from the same donor. It was found to express the NKTa clonotypic determinant as well as JT9 and JT10 (6). The lytic specificity of JT As shown in Table II, NKH1A was present on all clones that had been selected on the basis of one unique criteria, e.g., the capacity of killing K562 cells without apparent preimmunization.…”

“…The reactivity of anti-NKHlA and anti-NKH2 was tested using a series of nine cloned NK cell lines (Table II). JT1, JT3, JT9, and JT10 have been previously described in detail (5,6). JTlI was a clone derived from the same donor.…”

“…Cells in this group express T3 antigen in addition to T8 and TlI antigens and thus appear to have a complete mature T cell phenotype. Moreover, clones in this group have also been shown to express clonotypic receptor like structures, linked to T3 antigen in an analogous fashion to antigen-specific T cells (6). The second group of NK clones express different combinations of T lymphocyte-associated surface antigens including T1, T8, Tl 1, and/or T12, but lack the mature T cell differentiation antigen, T3.…”

Human T lymphocyte subsets. Functional heterogeneity and surface recognition structures.

“…It would be likely, therefore, that at the clonal level, effector cells with high affinity T3-Ti receptors for specific antigen exist that would be less dependent on T4 or T8 to interact with stimulator or target cells. Not surprisingly, such clones have been described, even occasionally in apparent contradiction to the usual T4/class II and T8/class I association (57,60,76 Complementary studies by other groups directed towards identifying T cell antigen receptor molecules have utilized the subtractive hybridization technique, by which they have respectively described the isolation of human and mouse cDNA clones which were T cell specific, and in the case of the murine clones, that identified genes that could be shown to be rearranged in these T cells but not in other cell types (78)(79)(80). The human T cell DNA clone encodes a predicted 35,000-mol wt polypeptide with strong homology to human Ig lambda light chain in both N-and C-terminal regions, and particularly in the area of the cysteine residues (78).…”