CD69-mediated pathway of lymphocyte activation: anti-CD69 monoclonal antibodies trigger the cytolytic activity of different lymphoid effector cells with the exception of cytolytic T lymphocytes expressing T cell receptor alpha/beta.

Abstract

SummaryThe effect of anti-CD69 monodonal antibodies (mAbs) on the induction of the cytolytic activity in different types of lymphoid effector cells has been investigated. Three anti-CD69 mAbs, including the reference mAb MLR3 and two new mAbs (c227 and 31C4), have been used. All cloned CD3-CD16 + natural killer (NK) cells belonging to different subsets (as defined by the surface expression of GL183 and/or EB6 antigens) were efficiently triggered by anti-CD69 mAbs and lysed P815 mastocytoma ceUs in a redirected killing assay. Triggering of the cytolytic activity could also be induced in CD3-CD16-NK clones, which fail to respond to other stimuli (including anti-CD16, anti-CD2 mAbs, or phytohemagglutinin). A similar triggering effect was detected in T call receptor (TCR) 3,/~ + clones belonging to different subsets. On the other hand, anti-CD69 mAbs could not induce triggering of the cytolytic activity in TCR cr + cytolytic dones. Since all thymocytes are known to express CD69 antigen after cell activation, we analyzed a series of phenotypically different cytolytic thymocyte populations and clones for their responsiveness to anti-CD69 mAb in a redirected killing assay. Again, anti-CD69 mAb triggered TCR 3,/~ + but not TCR ce/~ + thymocytes. Anti-CD69 mAb efficiently triggered the cytolytic activity of "early" thymocytes lines or clones (CD3-4-8-7 +), which lack all other known pathways of cell activation. Thus, it appears that CD69 molecules may initiate a pathway of activation of cytolytic functions common to a number of activated effector lymphocytes with the remarkable exception of TCR ot/B + cytolytic cells.

Adhesion of tumour-infiltrating lymphocytes to endothelium: a phenotypic and functional analysis

“…For instance, CD69 is a C-type lectin (Lopez-Cabera et al, 1993) likely to contribute to adhesion and CD38 has been implicated in binding to endothelium (Xu et al, 1994). Furthermore, both CD69 and CD38 are involved in signal transduction and cell activation (Nakamura et al, 1989;Moretta et al, 1991;Tugores et al, 1992;Xu et al, 1994) and CD30, a member of the TNF receptor family, could modulate TIL effector function by interacting with the CD30 ligand in the tumour (Faustman et al, 1982).…”

Tumor-Induced Apoptosis of Human IL-2-Activated NK Cells: Role of Natural Cytotoxicity Receptors

“…It has been shown that NK cells undergo apoptosis through the engagement of Fas molecule by FasL (16,17). Thus, we analyzed whether FasL/Fas interaction was involved in the NK cell death following the binding with tumor targets.…”

“…The anti-CD16 (NK1, IgG1, VD4, IgG1; KD1, IgG2a) mAb (10) and the anti-CD56 (TA181H12, IgG2a) mAb were obtained, as described (6,14,17,18). The anti-CD3 mAb (Leu4, IgG1), the anti-CD4 mAb (Leu3a, IgG1), the anti-CD8 mAb (Leu2a, IgG1), and the anti-CD56 mAb (Leu19, IgG1) were from BD Biosciences, and the anti-FasL (NOK-1, IgG1) was from BD Pharmingen.…”

“…One hundred microliters of supernatant (SN) were counted in a gamma counter, and percentage of 51 Cr-specific release was calculated, as described previously (16). In the redirected killing assay, the Fc␥R ϩ murine mastocytoma cell line P815 was used as target in the presence of saturating amounts (3 g/ml) of the indicated mAb (16,17) or in medium alone (nil) at the E:T ratio of 1:1. …”

“…Single fluorescence staining was performed, as described elsewhere (16,17). Briefly, aliquots of 10 5 cells were stained with the corresponding mAb, followed by PE-conjugated anti-isotype-specific GAM serum (Southern Biotechnology Associates), or with an unrelated mAb (BD Biosciences), followed by the fluorescent second reagent.…”