The use of human lymphoid cell line lymphokine preparations (LCL-LK) as working standards in the bioassay of human leucocyte migration inhibition factor (LIF).

The leucocyte migration inhibition test in agarose as described by Clausen (1971) was modified into a statistically designed assay of LIF activity using human polymorphonuclear leucocytes from single blood donors. Individual assays included a laboratory standard of lymphokine with LIF activity prepared from the culture supernatants of the RPMI 1788 human lymphoblastoid cell line (LCL-LK). Analysis of 157 LIF assays revealed simple criteria by which the acceptability of an individual assay could be judged before subjecting it to statistical analysis. The failure of LIF assays to meet these criteria of acceptability was particularly associated with low areas of control polymorph migration in the absence of lymphokine ('spontaneous migration'). We demonstrate that the statistically designed assay permits the measurement, with precision, of LIF activity in units/ml by reference to a working standard of LCL-LK. We illustrate the use of this assay in the measurement of LIF activity generated by tuberculin-stimulated human peripheral blood lymphocytes.

Involvement of cell surface macromolecules sensitive to alkylating ketones in lysis by human peripheral blood NK cells.

Natural cytotoxicity (mediated by the B73.1+ subset) of human peripheral blood lymphocytes against the K-562 erythroleukaemia cell line is dramatically inhibited in a dose-dependent manner, by the small molecular weight protease inhibitors, tosyl-L-lysyl chloromethyl ketone (TLCK) and tosylamide phenyl-ethyl-chloromethyl-ketone (TPCK), incorporated into the cytotoxicity assay or after brief effector cell (but not target cell) pre-treatment. The alkylating ketones primarily affect post-binding events in the lytic process by interference with cellular functions dependent upon protein synthesis. Although non-toxic under the conditions used, recovery of cytolytic function requires at least 72 h, implicating involvement of protein(s) with a minimum turnover time of 3 days. Protection of effector cell function from TLCK by prior treatment with the lectin Lens culinaris (lentil) agglutinin, which binds human peripheral blood lymphocytes to a three-fold greater extent than concanavalin A, indicated that the initial action of the agent is with cell surface rather than intracytoplasmic components. The data suggest that the alkylating ketones inhibit natural killer function by slowly reversible functional inactivation of cell-surface protease(s), which although not cytotoxic per se, may control the secretion of soluble lytic factors.

Proliferative and cytotoxic responses of human peripheral blood lymphocytes to autologous malignant effusions. An analysis at the clonal level.

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.

Role of MHC class-I antigens and the CD3 complex in the lysis of autologous human tumours by T-cell clones.

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.

Hepatitis B surface antigen and alpha-fetoprotein secreting human primary liver cell cancer in athymic mice.

A human primary liver cancer cell line which retains the property of synthesizing hepatitis B surface antigen has been successfully transplanted into nude (athymic) mice. The morphology of the heterotransplanted tumor is similar to that of a well-differentiated human primary liver cell cancer. It produces hepatitis B surface antigen, but there is no evidence of hepatitis B virion production: Hepatitis B core antigen is not detected in the PLC tissue, and serum is negative for hepatitis B e antigen. The nude mouse exhibits a resistance to the transplantation of the human primary liver cancer cells which can be modified by sublethal total body irradiation, suggesting involvement of an immunologic rejection mechanism. The heterotransplanted primary liver cell cancer also produces alpha-fetoprotein, as did the original tumor in vivo, although this marker was not detected during in vitro cell culture. The serum level of alpha-fetoprotein rises exponentially, enabling quantitative evaluation of tumor growth. The human primary liver cell cancer in nude mice provides an in vivo model for determination of tumor response to chemotherapeutic agents.

Adenine arabinoside therapy in HBsAg-positive chronic liver disease: a controlled study.

A controlled trial has been undertaken to evaluate adenine arabinoside in the treatment of hepatitis B surface antigen-positive chronic liver disease. Thirteen patients (7 hepatitis B virus DNA polymerase and hepatitis B e antigen-positive, 6 DNA polymerase negative and hepatitis B e antibody-positive) were treated with adenine arabinoside. Eleven comparable patients served as controls, and follow-up was for 6 mo. In the 7 hepatitis B e antigen-positive patients, adenine arabinoside produced a fall in DNA polymerase activity during treatment. When this effect was sustained, it was followed by a loss of e antigen (3 patients). Hepatitis B surface antigen concentrations and aspartate transaminase levels fell significantly at 6 mo (p less than 0.05) in the treated group compared with controls. In the hepatitis B e antibody-positive patients, adenine arabinoside treatment produced no significant change in hepatitis B surface antigen concentrations or aspartate transaminase levels at 6 mo as compared with controls. Adenine arabinoside would appear to reduce either transiently or permanently, hepatitis B virus replication, and it may therefore be useful in reducing the infectivity of some carriers of this virus. In the dose used, adenine arabinoside was ineffective in clearing hepatitis B surface antigen from the serum and eradicating hepatitis B virus from the liver, but combination with other antiviral or immunostimulant agents may enhance its therapeutic effectiveness.