No abstract

Peripheral blood lymphocytes (PBL) of 4 patients with malignant effusions were stimulated for 6 days with purified autologous tumour cells, before isolation of the lymphoblasts and cloning by limiting dilution in interleukin-2 (IL-2). Forty-five clones were analyzed for cytotoxicity (CTX) against autologous, allogeneic tumour and erythromyeloid K562 cells of known status with respect to expression of major histocompatibility complex (MHC) antigens, estimated by reaction with the W6/32 (anti HLA, -A, -B, -C monomorphic) and TDR 31.1 (anti HLA-DR) monoclonal antibodies (MAb). All 45 clones were CD3+. Twenty-five (56%) of them were cytotoxic for at least one target; 24 were autoreactive (restricted in 7); 17 were alloreactive; 16 were K562 reactive. Under comparable conditions autoreactivity was partially blocked by W6/32 in 12/20 effector:target combinations; alloreactivity in 8/13 and K562 reactivity in 0/14. Modulation of effector cell surface CD3 antigens by OKT3 monitored by flow cytometry reduced autoreactivity in 9/14 combinations, alloreactivity in 2/6 and K562 reactivity in 0/4. W6/32 blocking and T3 modulation of cytotoxicity were almost invariably concordant against the same target. The data suggest that, to accomplish lysis of autologous and allogeneic tumour targets, certain clones require MHC recognition and a functional CD3 complex, while for others with similar target cell repertoires, there is no such requirement. It is possible that T-cell clones responding to a tumour-associated antigen (TAA) in the context of self MHC antigens can also respond to an allogeneic class-I product in the absence of TAA, and/or that aberrant class-I antigen expression on autologous tumours accounts for the alloreactivity.

Peripheral blood lymphocytes from five patients were stimulated initially in mixed lymphocyte:tumour culture (MLTC) with autologous malignant effusions and cloned by limiting dilution in interleukin-2 prior to phenotyping and assay for different functional capabilities namely proliferative responsiveness to autologous and allogeneic tumours in the primed lymphocyte test (PLT) and cytotoxicity (CTX) toward a range of fresh tumour and cell line targets. For individual clones the two functional activities tended to be mutually exclusive. Clones (or 'cloids' containing more than one PLT precursor) from three of four tumours analysed were responsive to autologous tumour cells in the PLT of which two shared antigens with allogeneic tumours of similar tissue provenance. All phenotyped PLT positive clones were T3+T4+T8-. Cytotoxic clones were generated from all MLTCs. Their target cell repertoire (based on an analysis of greater than 30) was generally broad including cell lines sensitive to natural killer (NK) cells, and less frequently and to a weaker extent, fresh autologous and allogeneic tumours. An ovarian carcinoma was exceptional, insofar as the CTX of 8/9 clones was apparently restricted to the autologous tumour. Phenotypically cytotoxic clones were T3+T4-T8+, less usually T3+T4+T8-, but invariably B73.1- (a monoclonal antibody reactive with the peripheral blood NK subset). Analysis at the clonal level emphasises the diversity of responses to putative human tumour-associated antigens, and the need to identify the critical functionally active molecules in the MLTC.

No abstract