D.C. Dumonde

Application of an immortalized human endothelial cell line to the leucocyte : endothelial adherence assay

This report shows that an immortalized endothelial cell line (EA.hy 926) is able to substitute for secondary cultures of human umbilical vein endothelial cells (HUVEC) in the leucocyte:endothelial adherence assay. Enriched preparations of blood polymorphonuclear leucocytes, monocytes and resting and activated lymphocytes exhibited similar adherence characteristics to HUVEC and the EA.hy 926 cells. Cytokines such as tumour necrosis factor (TNF) act on endothelial cells to increase their adhesiveness for leucocytes and in this study there was no difference between TNF-treated HUVEC and EA.hy 926 cells in supporting the enhanced binding of leucocytes. The adherence promoting effect of TNF-treated EA.hy 926 cells appears to be dependent upon their endothelial properties since TNF treatment of A549 cells, the permanent human cell line used to generate the hybrid EA.hy 926 cells did not augment lymphocyte attachment. Monoclonal antibodies against CD11a and CD18 inhibited the binding of lymphocytes to untreated and TNF-treated HUVEC and EA.hy 926 cells and ICAM-1 expression was increased on both monolayers following treatment with TNF. The availability of a hybrid endothelial cell line whose adhesive properties are similar to those of recently isolated endothelial cells should benefit the study of factors that govern leucocyte-endothelial cell interactions and be advantageous to the longitudinal investigation of leucocyte adherence under static conditions.

Selective binding of peripheral blood lymphocytes to the walls of cerebral vessels in frozen sections of human brain

In order to identify the factors that control the binding of blood leucocytes to cerebral blood vessels we have modified and applied the frozen section assay of Stamper and Woodruff to the study of human brain. Cryostat sections of brain tissue obtained at post mortem were overlaid with blood lymphocytes and experimental conditions were defined which permitted optimum binding of the cells to transected blood vessel walls. The maximal binding of lymphocytes to cerebral vessels occurred when 6 x 10(6) lymphocytes were overlaid onto brain sections for 30 min at 7 degrees C with gentle agitation. Only a small proportion (0.01%) of the added lymphocytes bound to exposed cerebral vessels. However, lymphocytes were far more adherent than monocytes and polymorphonuclear cells (7-fold and 11-fold respectively: p < 0.001) and activation of lymphocytes with IL-2 enhanced their binding to blood vessel walls (mean 130% increase; p < 0.03). Further analysis revealed that CD4-positive T lymphocytes were the predominant cell population binding to the blood vessels. Antibody blocking studies showed that lymphocyte binding to cerebral blood vessels was inhibited by pretreating the lymphocytes with anti-CD11a, anti-CD18 or anti-CD49d (p < or = 0.02) and immunohistochemical studies revealed the presence of the counter-receptors ICAM-1 (CD54) and VCAM-1 (CD106) for these adhesion molecules in addition to the presence of E-selectin (CD62E) and P-selectin (CD62P) on the cerebral blood vessels. The establishment of a technique in situ which measures selective binding of CD4-positive peripheral lymphocytes to sections of cerebral blood vessels will assist in the molecular characterization of factors that control the interaction of leucocytes with the blood-brain barrier in health and disease.

Adoptive immunotherapy administered via the hepatic artery and intralesional interleukin-2 in hepatocellular carcinoma

We assessed the feasibility of using lymphokine-activated killer cells (adoptive immunotherapy) with infusions of interleukin-2 when given regionally in three patients with unresectable primary hepatocellular carcinoma (PHC). In 2 patients, 2 cycles, which included a bolus of LAK (10(7) to 10(8) cells followed by a 4-hourly infusion of IL-2 were administered via selective arterial catheterization of the hepatic artery. One further patient received 3 cycles of IL-2 alone by direct intralesional and perilesional injections. Minimal toxicity was observed and side effects such as fever were comparable to those observed with systemic infusions of IL-2 alone. Serial alpha-fetoprotein (AFP) levels initially fell but subsequently rose within 2 to 4 weeks of therapy. AFP levels had not reached pre-treatment values at 4 months in 2 patients, 1 of whom was alive and well at 15 months follow-up.

The Response of Tumor-Bearing Patients to the Injection of Lymphoid Cell Line Lymphokine

We began this work in 1976 at a time when lymphokines were becoming accepted as mediators of cellular immune responses and when consideration was being given to the immunodepression associated with progressive cancer and with its treatment. At that time, work on leukocyte interferon, dialyzable leukocyte transfer factor, and thymic extracts had established a precedent for the therapeutic investigation of biological materials in patients with otherwise irreversible neoplastic disease; and it seemed that lymphokines could also have therapeutic potential in human cancer (Hamblin et al., 1978). We were examining lymphokines generated by the cultured B-lymphoblastoid cell line RPMI 1788 as potential standards in the leukocyte migration test (see Hamblin et al., 1982); and when Papermaster et al. (1976) reported on the safe intralesional (i.l.) injection of RPMI 1788 lymphokine into human cutaneous metastases, we decided to use this source of lymphokine for the present study. With ethical permission and informed consent, we set out to extend knowledge of the histopathological responses to the i.d. and i.l. injection of RPMI 1788 lymphokine (“LCL-LK”) in patients with advanced cancer and to investigate the clinical, hematological, biochemical, and immunological responses to single and repeated i.v. injections of LCL-LK.