Activation of CD4+ and CD8+ lymphocyte subsets by streptozotocin in the popliteal lymph node assay. II. Comparison with acute graft-vs-host reaction in H-2 incompatible F1 mouse hybrids.

Changes in lymphocyte subsets during an acute GVH reaction were compared to STZ-induced PLN response in mice. The GVH reaction was induced locally by sc injection of parental C57Bl/6 [B6] spleen cells into (C57Bl/6 x DBA/2) F1 footpad [B6D2F1]. Early cell activation and time-related changes in T- and B-lymphocyte subsets were monitored during the onset of the GVH reaction by flow cytometry and immunophenotyping. Examination of cell size and chromatin decondensing for T- and B-cell subsets showed differences in activation profile during the early phase of the GVH reaction. The present study provides direct evidence for early in vivo activation of both CD4+ and CD8+ T-cells. Our data confirm the central role of T-cell activation in the induction of a GVH reaction and suggest that recirculatory host B-cells can play an important role in early GVH node enlargement. Overall, our comparative analysis supports the concept of polyclonal T-cell activation for both STZ-related and GVH-induced lymphoproliferation. Chemicals-induced lymphoproliferation leading to autoimmune reactions is a challenging issue. A number of drugs and chemicals have been tested in the PLNA assay for lymphoproliferative potential. We previously reported the activation and proliferation of T-cell subsets following STZ injection into murine footpads. The STZ-induced PLN enlargement and proliferation characteristics of T- and B-cell subsets were postulated to be similar to those of an acute allogeneic GVHR. In the present study, a cytometric analysis of T- and B-cell subsets in PLNs was performed during an acute allogeneic GVHR, for comparison purposes. Such a reaction results in a massive node enlargement five to ten times that seen after stimulation with conventional antigens. Acute GVHR is believed to be a direct consequence of the high frequency of alloreactive donor T-cells inducing a massive proliferation of B-cells, almost exclusively of host origin, in GVHR nodes. It is now widely accepted that donor T-cells activated as the result of exposure to foreign MHC antigens in the recipient, secrete various cytokines which assist the host B-cells and bypass the normal B-T cell cooperation. Induction of an acute GVHR, as in the parental B6--->recipient B6D2F1 model, requires the injection of CD4+ and CD8+ donor T-cells into an F1 recipient that differs from the parent at both MHC class I and II loci.(ABSTRACT TRUNCATED AT 400 WORDS)     

Transient inhibition of mixed lymphocyte reactivity by dieldrin in mice

Dieldrin, a non-aromatic organochlorinated pesticide, was shown to be a potent modulator of the immune system. We had earlier demonstrated that mice treated with a single sublethal dose of dieldrin showed an impaired antibody response and reduced viral restriction mediated by macrophages. These dieldrin-induced immunosuppressive effects were shown to be dose dependent, when administered by the oral or intraperitoneal (i.p.) route. This study was undertaken to investigate the effect of dieldrin on the T-cell immune response. Lymphoid cells from mice injected i.p. 7 days earlier with 36 mg/kg body weight (0.6 LD50) dieldrin were assessed for their ability to recognize a foreign antigen and to proliferate in a mixed lymphocyte reaction (MLR) at 4, 7, 14 and 24 days post-treatment. We have demonstrated a strong but transient inhibition of MLR at 7 days after pesticide exposure. This effect was reversible and could not be attributed to a direct cell cytotoxicity, nor to the modulation of the T-cell ratio in lymphoid organs. Since the mitogen response was not impaired at this time point, we suggest that T-cell ability to recognize a foreign antigen can be altered by dieldrin, but not the proliferative potential of the cells.     

Suppressive effect of low molecular weight fibrinogen degradation products on human and rat lymphocytes

Low molecular weight dialysable fibrinogen degradation products (LMW-FDP) at concentration of 25 to 50 μg/ml strongly inhibited spontaneous and phytohaemagglutinin (PHA) stimulated incorporation of ³H-thymidine into cultures of human pheripheral blood lymphocytes and of rat lymph node cells. Dialysable peptides derived during proteolysis of highly purified human factor VIII induced similar effect at concentration of 1000 μg/ml.     

Studies on the influence of thiols on lymphocytes (T-type lymphocytes) function.

Changes of the oxidation/reduction potential of the coupled -SH/SS low molecular sulfhydryl system in rat lymphocytes were determined after incubation of cells with D-penicillamine, cysteine and cysteine hydrazide, in concentration of thiols which did not disturb the response of the cells to phytohemagglutinin (PHA). Considerable increase of the -SH content in lymphocytes was observed after treatment of the cells with cysteine and cysteine hydrazide. Our findings suggest that the biological effect of thiols used in optimal concentrations and conditions might be coupled with the disturbance of the -SH/SS oxidation/reduction system in cells.     

Suppression of avidin processing and presentation by mouse macrophages after sublethal exposure to dieldrin

The molecular events in macrophage antigen processing and presentation were examined to determine the possible site(s) of cell-xenobiotic interaction. Antigenic processing by mouse peritoneal macrophages of a single protein antigen, avidin, was significantly suppressed following sublethal exposure of animals to an organochlorine pesticide, dieldrin. Exposure of C57B1/6 female mice to dieldrin affected the in vitro uptake of [methyl-14C]avidin by peritoneal macrophages and markedly decreased phagocytosis of fluorescein-labelled microspheres and Salmonella typhimurium. Release of the processed avidin, determined by immunochemical quantification of immunogenic avidin and by bioassay of immunogenicity of the released antigen, was also markedly affected. Dieldrin markedly affected presentation of avidin on the macrophage surface, observed by cytoimmunochemical staining of the antigen with fluorescent antibody and flow cytometry. Inhibition of the release of processed avidin was dieldrin dose- and time-dependent, following single sublethal intraperitoneal (ip) exposure to the pesticide. The antigenic properties of processed avidin, determined by biological assay using lymphocyte cultures of normal C57B1/6 mice primed with avidin, were proportional to the antigen concentration in supernatants of macrophage cultures, for both vehicle controls and dieldrin-exposed animals. This observation and analysis of the kinetics of release of processed avidin by macrophages from control and dieldrin-exposed animals suggested that the release of processed avidin, but not the immunogenicity of the antigen itself, was affected by the pesticide exposure. Generally, impairment of avidin processing and presentation appeared to be more dramatic than other pesticide-related injuries to macrophages, such as the uptake of the antigen. In conclusion, antigen processing could be a sensitive target for dieldrin-related injury of macrophage functional activities, which, in consequence, could produce suppression of the humoral immune response.     

Randomised phase II study of amrubicin as single agent or in combination with cisplatin versus cisplatin etoposide as first-line treatment in patients with extensive stage small cell lung cancer - EORTC 08062

Purpose

The EORTC 08062 phase II randomised trial investigated the activity and safety of single agent amrubicin, cisplatin combined with amrubicin, and cisplatin combined with etoposide as first line treatment in extensive disease (ED) small cell lung cancer (SCLC).

Patients and methods

Eligible patients with previously untreated ED-SCLC, WHO performance status (PS) 0–2 and measurable disease were randomised to 3 weekly cycles of either amrubicin alone 45 mg/m² i.v. day(d) 1–3 (A), cisplatin 60 mg/m² i.v. d1 and amrubicin 40 mg/m² i.v. d1–3 (PA), or cisplatin 75 mg/m² i.v. d1 and etoposide 100 mg/m² d1, d2–3 i.v./po (PE). The primary end-point was overall response rate (ORR) as assessed by local investigators (RECIST1.0 criteria). Secondary end-points were treatment toxicity, progression-free survival and overall survival.

Results

The number of randomised/eligible patients who started treatment was 33/28 in A, 33/30 in PA and 33/30 in PE, respectively. Grade (G) ?3 haematological toxicity in A, PA and PE was neutropenia (73%, 73%, 69%); thrombocytopenia (17%, 15%, 9.4%), anaemia (10%, 15%, 3.1%) and febrile neutropenia (13%, 18%, 6%). Early deaths, including treatment related, occurred in 1, 3 and 3 patients in A, PA and PE arms, respectively. Cardiac toxicity did not differ among the 3 arms. Out of 88 eligible patients who started treatment, ORR was 61%, (90% 1-sided confidence intervals [CI] 47–100%), 77% (CI 64–100%) and 63%, (CI 50–100%) for A, PA and PE respectively.

Conclusion

All regimens were active and PA met the criteria for further investigation, despite slightly higher haematological toxicity.     

INCREASED APOPTOSIS,CHANGES IN INTRACELLULAR Ca2+, AND FUNCTIONAL ALTERATIONS IN LYMPHOCYTES AND MACROPHAGES AFTER IN VITRO EXPOSURE TO STATIC MAGNETIC FIELD

Electromagnetic-related alteration of cellular functions is well documented for extremely low-frequency low-energy pulsing electromagnetic fields (ELF-EMF). In this study we examined the in vitro effects of static magnetic fields (SMF) on the cellular immune parameters of the C57Bl/ 6 murine macrophages, spleen lymphocytes, and thymic cells. The cells were exposed in vitro for 24 h at 37 C, 5% CO2, to 250-1500 G SMF. Exposure to the SMF resulted in the decreased phagocytic uptake of fluorescent latex microspheres, which was accompanied by an increased intracellular Ca2+ level in macrophages. Exposure to SMF decreased mitogenic responses in lymphocytes, as determined by incorporation of \[3H]thymidine into the cells. This was associated with the increased Ca2+ influx in concanavalin A-stimulated lymphocytes. Furthermore, exposure to SMF produced markedly increased apoptosis of thymic cells, as determined by flow cytometry. Overall, in vitro exposure of immunocompetent cells to 250-1500 G SMF altered several functional parameters of C57Bl/6 murine macrophages, thymocytes, and spleen lymphocytes.     

Suppression of MHV3 virus-activated macrophages by dieldrin

Dieldrin (36 mg/kg body weight) administered intraperitoneally prolonged recovery from infection with mouse hepatitis virus 3 (MHV3) in the genetically-resistant A/J strain, affected the humoral anti-MHV3 IgG immune response, and inhibited the intrinsic antiviral activity of peritoneal macrophages upon in vitro rechallenge with the virus. Infection of untreated A/J animals and vehicle controls with MHV3 resulted in marked and reproducible activation of peritoneal macrophages, observed in vitro as resistance to MHV3-cytopathic effects 48 hr after rechallenge with the virus, whereas exposure to dieldrin resulted in apparent loss of the intrinsic capacity of cells to restrict replication of MHV3 and to protect them from cytolysis. In addition, in vitro treatment of MHV3 virus-activated macrophages with dieldrin, mitomycin C and X-irradiation, inhibited the intrinsic capacity of cells to restrict MHV3 replication. This mechanism of cellular restriction of the virus by MHV3-activated macrophages from the resistant A/J strain appeared to be one of the sensitive targets for the suppressive action of dieldrin on host resistance, as no major changes in macrophage cellular parameters were observed in in vitro studies of cell viability, adherence to plastic, and superoxide anion generation; the increased cell yield in the peritoneal exudates during MHV3 virus infection was not affected by dieldrin exposure; and the attachment and uptake of [3H]MHV3 by virus-activated macrophages was shown to be unchanged by dieldrin exposure.     

Abrogation of graft-versus-host reaction by dieldrin in mice

Sublethal exposure to the organochlorine pesticide, dieldrin, decreased the T-cell immune response in mice. Indeed, a transient inhibition of the mixed lymphocyte reactivity (MLR) was noted at 7 days after intraperitoneal exposure to 0.6 LD50 dieldrin. The present study was undertaken to further investigate the effects of dieldrin on the T-cell immune response, using the graft-versus-host reaction (GVHR) as a model, in order to assess T-cell subset efficiency. Lymphoid cells of A/J mice injected intraperitoneally 7 days earlier with 36 mg/kg body weight dieldrin were transferred into H-2-incompatible F1 hybrids. With this model, known to induce a marked GVHR, we have observed that dieldrin inhibited the potential of parental cells to induce a GVHR in hybrid mice. This effect could not be attributed to a direct cell cytotoxicity, nor to the modulation of major T-cell subsets as shown by thymic and peripheral T-cell subpopulation analysis. Collaboration processes between these cellular subsets seem to represent a potential site for the dieldrin-induced suppression.