CoCanCPG. Coordination of Cancer Clinical Practice in Europe

All European countries are facing common challenges for delivering appropriate, evidence-based care to patients with cancer. Despite tangible improvements in diagnosis and treatment, marked differences in cancer survival exist throughout Europe. The reliable translation of new research evidence into consistent patient-oriented strategies is a key endeavour to overcome inequalities in healthcare. Clinical-practice guidelines are important tools for improving quality of care by informing professionals and patients about the most appropriate clinical practice. Guideline programmes in different countries use similar strategies to achieve similar goals. This results in unnecessary duplication of effort and inefficient use of resources. While different initiatives at the international level have attempted to improve the quality of guidelines, less investment has been made to overcome existing fragmentation and duplication of effort in cancer guideline development and research. To provide added value to existing initiatives and foster equitable access to evidence-based cancer care in Europe, CoCanCPG will establish cooperation between cancer guideline programmes. CoCanCPG is an ERA-Net coordinated by the French National Cancer Institute with 17 partners from 11 countries. The CoCanCPG partners will achieve their goal through an ambitious, step-wise approach with a long-term perspective, involving: 1. implementing a common framework for sharing knowledge and skills; 2. developing shared activities for guideline development; 3. assembling a critical mass for pertinent research into guideline methods; 4. implementing an appropriate framework for cooperation. Successful development of joint activities involves learning how to adopt common quality standards and how to share responsibilities, while taking into account the cultural and organisational diversity of the participating organisations. Languages barriers and different organisational settings add a level of complexity to setting up transnational collaboration. Through its activities, CoCanCPG will make an important contribution towards better access to evidence-based cancer practices and thus contribute to reducing inequalities and improving care for patients with cancer across Europe.

When can temporally focused excitation be axially shifted by dispersion?

Temporal focusing (TF) allows for axially confined wide-field multi-photon excitation at the temporal focal plane. For temporally focused Gaussian beams, it was shown both theoretically and experimentally that the temporal focus plane can be shifted by applying a quadratic spectral phase to the incident beam. However, the case for more complex wave-fronts is quite different. Here we study the temporal focus plane shift (TFS) for a broader class of excitation profiles, with particular emphasis on the case of temporally focused computer generated holography (CGH) which allows for generation of arbitrary, yet speckled, 2D patterns. We present an analytical, numerical and experimental study of this phenomenon. The TFS is found to depend mainly on the autocorrelation of the CGH pattern in the direction of the beam dispersion after the grating in the TF setup. This provides a pathway for 3D control of multi-photon excitation patterns.

IRON CHELATORS: CORRELATION BETWEEN EFFECTS ON PLASMODIUM SPP. AND IMMUNE FUNCTIONS

Iron chelating agents, which permeate through erythrocytic and parasite membranes, are effective against Plasmodium falciparum in vitro. However, the protective effect in humans is transient. We examined the antiplasmodial capacity of several iron chelators in vitro and in vivo. The chelators 3/3hb/2m and 3/2hb/b (together, MoB) were more effective against P. falciparum in vitro than desferrioxamine (DFO) and Salicylaldehyde isonicotinoyl hydrazone (SIH) (together, DoS). Despite similar pharmacokinetics of all iron chelators, mice infected with Plasmodium vinckei and treated with MoB succumbed to malaria, whereas DoS-treated mice survived. However, even in the surviving mice, peak parasitemias were above 30%. These results indicate that the direct effects of the drugs on the parasites were not responsible alone for the complete recovery of the mice. We suggest that the recovery is related to differential effects of the drugs on various immune functions. We concentrated on the effect of the iron chelators on B cell and T cell proliferation and on allogeneic stimulation (MLR), interleukin-10 (IL-10), gamma-interferon (gamma-IFN), tumor necrosis factor-alpha (TNF-alpha), and radical production. All the iron chelators examined inhibited the in vitro proliferation of B cells and T cells, and MLR. This may explain why iron chelators are only slightly efficient in treating human malaria. However, the inhibitory effects of MoB on B cell and T cell proliferation and on MLR were more pronounced than those of DoS. In addition, the release of free radicals by effector cells was inhibited to a greater extent by MoB than by DoS. These results may explain why MoB, which was more efficient in vitro, was not effective in vivo. The DoS effects on the in vitro secretion of cytokines correlate with their in vivo effect; there was a decrease of IL-10 and a parallel increase in gamma-IFN and TNF-alpha production by human mononuclear cells. MoB, which could not rescue the animals from malaria, did not affect IL-10 and TNF-alpha, but reduced gamma-IFN levels. Identical results were obtained when using monocytes instead of mononuclear cells (except for gamma-IFN, which is not produced by monocytes). Our results indicate that an iron chelator, or any antiparasitic drug that kills the parasites in vitro, should also be selected for further evaluation on the basis of its reaction with immune components; it should not interfere with crucial protective immunological processes, but it may still alleviate parasitemia by positive immune modulation.

Sustained exposure to bacterial antigen induces interferon-γ-dependent T cell receptor ζ down-regulation and impaired T cell function

T cell antigen receptor zeta chain down-regulation and impaired in vitro T cell function have been described in cancer and autoimmune and infectious diseases. However, the immunological basis for this phenomenon is unknown. Sustained exposure to antigen and chronic systemic inflammation, factors shared by the various pathologies, might account for this phenomenon. We developed an in vivo experimental system that mimics these conditions and show that sustained exposure of mice to bacterial antigens was sufficient to induce T cell antigen receptor zeta chain down-regulation and impair T cell function, provided an interferon-gamma-dependent T helper type 1 immune response developed. This indicates zeta chain down-regulation could be a physiological response that attenuates an exacerbated immune response. However, it can act as a 'double-edged sword', impairing immune responses to chronic diseases.

Correlation between enhancement of graft-versus-leukemia effects following allogeneic bone marrow transplantation by rIL-2 and increased frequency of cytotoxic T-lymphocyte precursors in murine myeloid leukemia

A model of mouse acute myeloid leukemia (mAML) was used to study the effector mechanism mediating the graft-versus-leukemia (GVL) effects in recipients of allogeneic bone marrow cells (BMC). mAML-bearing SJL/J (H-2s) mice were lethally irradiated and then transplanted with a mixture of BMC and spleen cells (SC) derived from normal syngeneic or allogeneic mice. To augment the GVL effect, recipients were injected intraperitoneally with recombinant human interleukin-2 (rIL-2) (1.2 x 10(5) IU) for 3 consecutive days, starting one day post BMC + SC transplantation. Spleen cells from treated recipients were adoptively transferred to untreated secondary SJL/J mice to test for the existence of residual tumor cells. All the secondary recipients of SC from mAML-bearing SJL/J mice rescued with syngeneic (SJL/J) or allogeneic (B10.S) BMC+SC (H-2s) differing at minor antigens of the histocompatibility complex (MiHC) developed leukemia and died. In sharp contrast, none of the secondary recipients of SC obtained from identical mAML-bearing mice rescued with B10.S BMC + SC but activated in vivo with IL-2 developed leukemia. Adoptive recipients of SC obtained from mAML-bearing recipients of major histocompatibility complex (MHC)-disparate (C57BL/6, H-2b) cells remained free of leukemia regardless of the use of rIL-2. In parallel with the in vivo findings, a 4-day in vitro exposure of splenocytes to 6 x 10(3) IU/ml rIL-2 resulted in a 5- to 20-fold increase in the frequency of alloreactive cytotoxic T-lymphocyte (CTL) precursors (CTLp) across MiHC and MHC barriers and a 2- to 6-fold increase in their cytotoxic activity. Our data suggest that augmentation of GVL effects by rIL-2 may be due to CTL activation by rIL-2, not excluding the potential beneficial role of rIL-2-activated allogeneic natural killer cells and MHC non-restricted killer cells. Cumulatively, our results suggest potentially beneficial effects of rIL-2, when used jointly with bone marrow transplantation or allogeneic cell therapy, on eradication of leukemia.

Induction of preferential cytotoxicity against allogeneic mouse lymphoma cells: in vitro and in vivo studies

The aim of this study was to activate, in mixed leukocyte/tumor cell cultures (MLTC), cytotoxic lymphocytes exhibiting preferential activity in vitro and in vivo towards allogeneic mouse lymphoma cells. Whereas the lymphoma target cells were readily lysed by the MLTC-derived lymphocytes, the cytotoxicity against the corresponding allogeneic concanavalin-A(ConA)-induced lymphoblasts was more than tenfold lower. Both activities were mediated by CD3+, TCR+, CD8+, CD4- cytotoxic T cells (CTL). ConA-induced lymphoblasts were readily lysed by anti-Thy1.2 antibodies and complement, by CTL derived from mixed leukocyte cultures (MLC) and by the MLTC-derived CTL in the presence of ConA, indicating that the lymphoblasts are not merely less lysable than the lymphoma cells but that the latter are specifically recognized by the CTL. Lymphoblasts poorly competed with 51Cr-labeled lymphoma cells in a "cold"-target competition assay, suggesting that the MLTC-derived CTL largely recognize epitopes expressed only by the lymphoma cells. Furthermore, analysis of the cytotoxic activity of more than 500 MLTC-derived CTL oligoclones and over 30 clones revealed that one-third of them were cytotoxic only against the allogeneic lymphoma cells, one-third were reactive against both the lymphoma and the allogeneic lymphoblast target cells and the remainder were not cytotoxic at all. Upon injection into sublethally irradiated, lymphoma-bearing allogeneic mice, the MLTC-derived CTL cured 56% of the recipients and caused graft versus host disease (GVHD) is only 22%, whereas CTL activated in MLC against allogeneic splenocytes were therapeutically ineffective and caused lethal GVHD in 89% of the recipients. Although the therapeutic efficacy of the in vitro-generated antitumor CTL was demonstrated against experimental lymphoma lines, this strategy might prove effective in tumor immunotherapy in conjunction with other modalities.

Heat inactivation of fetal calf serum is not required for in vitro measurement of lymphocyte functions

This study was undertaken to test whether fetal calf serum (FCS) must be heat inactivated before use in tissue culture. We tested various immune functions of lymphocytes growing in medium containing non-treated and heat-inactivated FCS. The data clearly show that heat inactivation of the serum is not mandatory. In some cases, the addition of untreated FCS resulted in elevated response levels, while maintaining immune function specificity.

Mouse lymphoblasts lose their immunogenicity and susceptibility to specific cytotoxic T lymphocyte lysis during maintenance in culture

This study was undertaken to search for possible mechanisms by which T-cell lines become non-immunogenic and refractory to cellular-mediated lysis during culture. We demonstrate that mouse lymphoblasts (LB) lost their susceptibility to specific cytotoxic T lymphocyte (CTL)-mediated lysis following culture for more than 5 days in the presence interleukin-2 (IL-2), IL-7 but not IL-4. In contrast, the cultured lymphoblasts (CLB) were efficiently lysed by specific antibody and C' and by CTL in the presence of concanavalin A. In addition, CLB did not inhibit cytotoxicity against LB in a cold target competition assay, indicating that CLB and LB differ in the expression of certain surface molecules. Indeed, a significantly lower expression of H-2D class I antigen, the Fas antigen and the adhesion molecules intracelluar adhesion molecule-1 (ICAM-1) and very late activation antigen-4 (VLA-4) was observed on the CLB surface. Consequently, CLB could not form conjugates with specific CTL, a prerequisite for CTL-mediated lysis. In addition, there was a marked decrease in CLB immunogenicity: the cultured cells were unable to stimulate allogeneic spleen cells in mixed lymphocyte culture nor could they induce a cytotoxic response following their injection into allogeneic mice. The reduced immunogenicity enabled the prolonged survival of active CLB in an allogeneic host. We suggest that the extended survival in an allogeneic tumour-bearing host of cultured, hence weakly immunogenic, anti-tumour CTL, will enable them the in vivo implementation of their anti-tumour activity.

Visual characterization of recombination at FRT-gusA loci in transgenic tobacco mediated by constitutive expression of the native FLP recombinase

FLP/FRT-mediated site-specific recombination was studied with a recombination-reporter gene system which allows visualization of β-glucuronidase (GUS) expression after site-specific excisional activation of a silent gusA gene. This system was used for characterization of the functional activity of the Saccharomyces cerevisiae native FLP recombinase driven by the cauliflower mosaic virus (CaMV) 35s promoter [linked to the tobacco mosaic virus (TMV) omega translational leader] in mediating site-specific recombination of chromosomal FRT sites in tobacco FLP x FRT-reporter hybrids. Six hybrids were generated from crosses of lines containing either a stably integrated recombination-reporter or a FLP-expression construct. The activated gusA phenotype was specific to hybrid progenies and was not observed in either parental plants or their selfed progenies. Recombination efficiency in whole seedlings was estimated by the percent of radioactivity on a Southern blot which was incorporated into the recombined DNA product. Estimated efficiency mean values for the six crosses ranged from 5.2 to 52.0%. Histochemical analysis in hybrid plants visualized GUS activity with variable chimeric patterns and intensities. Recombination efficiency and GUS expression varied both among and within crosses, while higher recombination efficiency coincided with larger and more intense patterns of GUS activity. These data suggest that recombination is induced randomly during somatic developmental stages and that the pattern and intensity generated in a given plant are affected by factors imposing varibility not only between but also within crosses. Additionally, while recombination in a population of FLP/FRT hybrids may occur in all plants, recombination efficiency may still be low in any given plant. The activity of the native, as compared to a modified, FLP (Kilby et al. 1995) in the activation of transgenic traits in tobacco is discussed.

Prediction by a modified mixed leukocyte reaction assay of graft-versus-host disease and graft rejection after allogeneic bone marrow transplantation

In this report we describe a modified, sensitive MLR test that appears to detect fine antigenic disparities between HLA-identical siblings confirmed as such by serology and the standard MLR test. In a group of 40 consecutive allogeneic bone marrow transplants, reactivity detected by the modified MLR test correlated with the development of rejection of matched marrow grafts and onset of acute graft vs. host disease (aGVHD). Thus, 13/15 positively reacting patient/donor pairs developed one of these complications (P < 0.001), while only 2/25 developed aGVHD in the negatively reacting group. This test may be useful for selecting the most compatible donor when several potential donors are available.

Cytokine-induced resistance to microbial infections in normal, immunosuppressed and bone marrow transplanted mice

We studied the efficacy of in vivo and in vitro treatments with IL-1, IL-2, IL-3, and GM-CSF in the protection against bacterial (Salmonella typhimurium), fungal (Candida albicans) and viral (influenza virus A/PR8) infections, of normal, sublethally irradiated and lethally irradiated, bone marrow (BM) reconstituted mice. In parallel, the cytokines were tested for their ability to potentiate hematopoietic activity in vitro and in vivo. We demonstrate that, under the experimental conditions employed, IL-1 had the best protective activity against the three micro-organisms in both normal and immunocompromised mice when administered in vivo. Administration of IL-2 led to increased resistance in normal but not in immunodeficient mice, whereas GM-CSF had no beneficial effects. In contrast, preincubation of BM cells in these cytokines, singly or combined, prior to transplantation to lethally irradiated mice, did not confer protection against subsequent infection, although it increased the number of BM derived CFU-GM in culture (except in the case of IL-2). Administration of IL-1 or GM-CSF to BM transplanted mice facilitated WBC recovery, whereas IL-2 delayed it. Collectively, the data suggest that IL-1, alone or combined with other cytokines, may be beneficial in the prevention or treatment of microbial infections in immunocompromised and BM transplanted patients. It can also be concluded that enhanced hematopoietic recovery may not always coincide with the development of resistance to micro-organisms.

Chemo-immunotherapy of murine solid tumors: enhanced therapeutic effects by interleukin-2 combined with interferon alpha and the role of specific T cells

The aim of the present study has been to assess the therapeutic efficacy of various cytokines, singly or in combination, with and without chemotherapy (cyclophosphamide, Cy), in mice carrying advanced, weakly immunogenic tumors (MCA-105 sarcoma, M109 carcinoma). Treatment of animals with i.p. growths or experimental pulmonary metastases began 8-18 days after i.p. or i.v. tumor cell inoculation respectively. None of the cytokines tested [interleukin-2 (IL-2), interferon alpha (IFN alpha), tumor necrosis factor alpha (TNF alpha) and macrophage-colony-stimulating factor (M-CSF)] nor Cy had by itself a significant curative effect. A synergistic therapeutic effect was obtained with IL-2 or IFN alpha (but not with TNF alpha or M-CSF) in combination with Cy. The most efficacious regimen (65%-90% cure of mice carrying i.p. tumors) was the combination of Cy+IL-2+IFN alpha. Preliminary experiments suggested that sequential administration of these cytokines might be more beneficial than concurrent administration. Following successful immunotherapy, long-term (3-6 months) survivors showed a tumor-specific resistance to a second tumor challenge and their spleen contained an increased number of specific antitumor cytotoxic T lymphocyte precursors (5- to 20-fold, compared to control mice). In vitro and in vivo cell-depletion experiments using monoclonal antibodies revealed that T cells (primarily CD8), but not NK cells, are crucial for the therapeutic effects. This study indicates that a potent specific antitumor T cell immunity can be elicited against advanced weakly immunogenic tumors by combining chemotherapy (Cy) with IL-2 and IFN alpha.

A short human and mouse MLR assay utilizing lymphokine (IL-2, IL-3) secretion as an early activation event

The mixed leukocyte reaction is the only functional in vitro assay currently employed for confirmation of MHC matching between bone marrow recipients and their prospective donors and for MHC class II (HLA-Dw) typing. This assay is, however, time-consuming (6 days for human MLR), whereas for clinical purposes results are often required much earlier. In an attempt to shorten the MLR incubation period, we tested IL-2 (in human MLR) and IL-2/IL-3 (in mouse MLR) production as an indication of early stages of T cell activation. We here describe a shorter assay in which IL-2 and IL-3 secretion during MLR was assessed by adding the respective lymphokine-dependent cell lines either to the MLR supernatants or directly to the original MLR cultures, using the colorimetric (3-[4,5 Dimethylthiazol-2-yl]-2.5-diphenyltetrazolium bromide) (MTT) technique or the 3H-thymidine incorporation assay. In both human and mouse MLR systems, lymphokine production peaked at 24-48 hr after culture initiation, allowing tests to be completed within 48 to 72 hr. Weak MLR responses, as detected by lymphokine production, could be considerably amplified by irradiating (250-1000 cGy) the responder cells and by adding heparin (1-10 U/ml) to the cultures. The results obtained by this novel procedure correlated with those obtained by the standard 6-day human MLR assay in over 250 combinations tested thus far, and therefore it may replace the standard MLR procedure.

Cytotoxic T lymphocytes reactive against a syngeneic murine tumor and their specific suppressor T cells are both elicited by in vitro allosensitization

Sensitization of C57BL/6 (B6, H-2b) splenocytes against normal BALB/c (H-2d) leukocytes (B6 a/BALB) in bulk MLC induced CTL reactive against the syngeneic (H-2b) nonimmunogenic lymphoma PIR-2, in addition to the CTL directed against the corresponding (H-2d) allotargets. However, MLC-derived lymphocytes did not directly exhibit anti-PIR-2 cytotoxicity in spite of the high anti-PIR-2 CTL frequency (up to 1/20) among them, as demonstrated by the limiting dilution culture (LDC) technique. The present study was undertaken to resolve this contradiction. We found that anti-PIR-2 cytotoxicity could be detected only when B6 a/BALB MLC-derived responding cells were plated in LDC at low numbers (less than 200) of cells/well. In contrast, increasing the number of the plated cells to 500-5,000 resulted in a gradual decrease in the percentage of wells cytotoxically reactive against PIR-2, whereas the percentage of wells exhibiting cytotoxicity against the allotargets remained unchanged (100%). This decrease of anti-PIR-2 cytotoxicity in LDC and the lack of anti-PIR-2 reactivity among MLC-derived lymphocytes were shown by mixing experiments to result from the activity of radioresistant Thy-1+, Lyt-2+, L3T4- suppressor cells, blocking the anti-PIR-2 cytotoxicity at the effector phase. The suppression was specific as indicated by the following observations: (a) freshly obtained B6 splenocytes, cultured unsensitized B6 splenocytes, mitogen-induced B6 lymphoblasts, B6 LAK cells, or B6 a/B6 MLC-derived lymphocytes were not suppressive; (b) anti-PIR-2 cytotoxicity elicited in B6 a/BALB LDC was suppressed only by lymphocytes derived from B6 a/BALB MLC and not from B6 a/C3H (H-2k) MLC; and (c) B6 a/BALB MLC-induced suppressor cells could be adsorbed on monolayers of BALB/c but not of C3H lymphoblasts. Since both syngeneic tumor and allogeneic target cells were lysed by the same clonal cell population but only the antisyngeneic activity was suppressed, we suggest that a single CTL can exhibit two cytotoxic activities that are differentially affected by the described suppressor cells. This mode of suppression may play a role in controlling autoimmune reactivity.

Allosensitization in IL-2-containing limiting dilution cultures generates cytotoxic T lymphocytes (CTL) rather than LAK cells reactive with a syngeneic nonimmunogenic murine tumor

We have previously demonstrated that high frequency (1/20) of potent cytotoxic cells reactive with the nonimmunogenic lymphoma PIR-2 of C57BL/6 (B6, H-2b) origin, can be obtained by allosensitization of syngeneic B6 splenocytes against BALB/c (H-2d) splenocytes in limiting dilution cultures (LDC). Since a high concentration (250 U/ml) of exogenous interleukin 2 (IL-2), sufficient for the elicitation of lymphokine-activated killer (LAK) cells, was used in the LDC, and because the LDC-derived cytotoxic cells were active against a wide spectrum of target cells, we investigated whether the anti PIR-2 effector cells are LAK cells or cytotoxic T lymphocytes (CTL). We found that depletion from the B6 responder cell population of Lyt2+ (CTL precursors), but not of asialo GM1+ (LAK cell precursors), prior to LDC, results in the ablation of anti PIR-2 activity. When B6 splenocytes were plated in LDC with IL-2, in the absence of allogeneic stimulating cells, the resulting anti PIR-2 activity was greater than 10- to 500-fold lower than that obtained in LDC in the presence of allogeneic stimulating cells and IL-2. These and other observations suggest that the cytotoxic response against syngeneic tumors elicited by alloantigens in LDC is mediated by CTL rather than LAK cells, and that allogeneic sensitization in LDC can provide a means for the generation of CTL against syngeneic, nonimmunogenic tumors.

Chemo-immunotherapy of murine tumors using interleukin-2 (IL-2) and cyclophosphamide. IL-2 can facilitate or inhibit tumor growth depending on the sequence of treatment and the tumor type

The antitumor effect of interleukin-2 (IL-2), alone and in combination with cyclophosphamide was assessed in mice with established sarcoma (MCA 105, H-2b), carcinoma (M109, H-2d) and T lymphoma (PIR-2, H-2b). Whereas administration of IL-2 alone (5 x 10(4)-10 x 10(4) U, i.p. twice daily, for 4-8 consecutive days) prolonged the survival of mice with the solid neoplasms, it enhanced tumor growth and decreased survival of mice with the lymphoma. In the PIR-2 lymphoma, no IL-2 receptor (TAC) could be detected, nor could we demonstrate IL-2 tumor growth stimulation in vitro. A synergistic therapeutic effect was achieved in mice with the solid tumors, but not in mice with the lymphoma, only when IL-2 was given 1-4 days after cyclophosphamide (100-200 mg/kg). Conversely, administration of IL-2 1-4 days prior to cyclophosphamide resulted, in all three tumor systems, in enhanced tumor growth and in decreased survival as compared with mice receiving cyclophosphamide alone. Similarly, treatment with IL-2 both before and after cyclophosphamide was less efficacious than a single course of IL-2 given afterwards. It is concluded that for maximal therapeutic efficacy, IL-2 should be administered following chemotherapy, and that certain tumors may respond adversely to IL-2 treatment.

In vitro and in vivo cytokine-induced facilitation of immunohematopoietic reconstitution in mice undergoing bone marrow transplantation

The aim of this study was to test whether colony stimulating factors (CSF) and other cytokines facilitate the recovery of a variety of immunohematopoietic functions in lethally irradiated mice undergoing bone marrow transplantation (BMT). Two experimental systems were employed: (a) lethally irradiated mice transplanted with syngeneic or T cell-depleted semi-allogeneic bone marrow (BM) cells (0.1-10 x 10(6)), subsequently treated by multiple doses of cytokines; and (b) lethally irradiated mice transplanted with BM cells that had previously been cultivated with cytokines. The cytokines used were: pure natural mouse interleukin-3 (IL-3); recombinant mouse granulocyte-macrophage CSF (rGM-CSF); recombinant human interleukin-2 (rIL-2); and crude cytokine preparations obtained from the culture supernatants of murine leukemia WEHI-3b cells (containing mainly IL-3), and of phorbol myristate acetate (PMA)-stimulated EL4 leukemia cells and concanavalin A-stimulated rat splenocytes (each containing a multitude of cytokines). For BM cultures (1-9 days), the cytokines were used at a dosage of 1-100 U/ml; for in vivo treatment, 2 x 10(2)-5 x 10(4) units were administered intraperitoneally and subcutaneously at different schedules for varying periods (1-3 weeks). The following parameters were tested 1-10 weeks post-BMT: white blood cell count, colony formation in agar and in the spleen of lethally irradiated mice, proliferative responses to mitogens and alloantigens, allocytotoxicity and antibody production (serum agglutinins and plaque-forming cells) against sheep red blood cells. Under appropriate conditions, cytokine treatment either in vitro or in vivo significantly enhanced (2- to 50-fold compared with controls) most functions tested at 2-8 weeks post-BMT, and shortened the time interval required for full immunohematopoietic recovery by 2-5 weeks. In recipients of semi-allogeneic, T lymphocyte-depleted BM no evidence of graft-versus-host disease was found. It is suggested that judicious application in vitro and/or in vivo of certain pure cytokines (e.g. GM-CSF, IL-3) or cytokine 'cocktails' might be beneficial in enhancing hematopoiesis and in the treatment of immunodeficiency associated with BMT.

Typing of HLA class II and class I antigens using PHA-activated, IL-2-propagated T lymphocytes

We describe here a simple procedure, by which HLA class II antigens can be accurately and reliably identified in those patients where there is minimal or absent expression of HLA-DR,DQw antigens on B cells, or when the total number of leukocytes recovered from the patients do not permit reliable typing. Ficoll-Hypaque-separated peripheral blood mononuclear leukocytes, fresh or cryopreserved, were activated by PHA and then propagated in IL-2-containing medium until enough cells for typing were obtained (usually 7-14 days). At this stage, the cultured cells were shown to be primarily T cells (greater than 90% CD3+). Since the activated T cells propagate in the presence of IL-2, even a small number (10(4] of fresh or cryopreserved patients' cells suffice for this protocol. To date we have been able to successfully HLA-DR,DQw type 34/34 bone marrow transplantation candidates and 12/12 long-term dialysis patients, who were untypable using fresh cells. HLA-DR,DQw antigens on activated T cells from normal individuals were identical to those found on their uncultured B cells. In addition, class I antigens that were undetectable on the uncultured cells of one patient could be identified on activated T cells. The HLA antigens identified on the patients' activated T cells were confirmed by phenotypic analysis of cells from family members.

Suppressor T cells in allogeneic bone marrow chimeras

Immunosuppression is believed to play a role in the maintenance of stable bone marrow (BM) chimeras. This study investigates the nature and specificity of the suppression that lymphocytes from allogeneic BM chimeras exert upon the alloreactivity of donor and recipient lymphocytes. Lethally irradiated CBA/J (H-2k) mice were infused with 10(7) unseparated (WBM) or T cell-depleted BM (TDBM) cells of B10.BR mice (H-2k, disparate at minor histocompatibility antigens). Mixtures consisting of spleen cells (SC) from BM chimeras and SC from either normal donor, recipient, or third party (C3H, H-2k) mice, were sensitized with irradiated BALB/c (H-2d) leukocytes, then assayed for proliferative and anti-H-2d cytotoxic activity and compared with those of appropriate control cultures. The alloreactivity of all three types of normal SC was non-specifically suppressed by SC from both WBM and TDBM chimeras taken 2 weeks post-BM transplantation (BMT). In contrast, at 4 weeks post-BMT, SC from both chimeras suppressed the alloreactivity of recipient-type cells whereas only SC from WBM, but not from TDBM chimeras, suppressed normal donor-type response, and neither could suppress the response of normal third party cells. The suppression of donor-type alloreactivity diminished with time, while that exerted on recipient-type lasted for at least 10 weeks post-BMT. The suppression of donor alloreactivity was mediated by radioresistant Thy1.2+, Lyt1+2+ cells while that exerted upon recipient's alloreactivity was mediated by radiosensitive Thy1.2+, Lyt1+2- cells. Both types of suppressor cells were of donor origin. The potential biological role of the suppressive activity in the engraftment of allogeneic BM is discussed.

Bone marrow transplantation with T-cell-depleted grafts. II. Reconstitution of immunohemopoietic functions in lethally irradiated mice transplanted with unseparated or T-cell-depleted bone marrow grafts disparate at minor histocompatibility antigens

Graft-versus-host disease (GVHD), a serious complication of allogeneic bone marrow transplantation (BMT), can be prevented by in vitro depletion of T cells from the bone marrow (BM) prior to transplantation. The purpose of this study was to assess the role of BMT cells in the reconstitution of various immune functions following BMT across minor histocompatibility barriers. Lethally irradiated CBA/J (H-2k) mice were grafted with either 10(7) unseparated or T-cell-depleted BM cells from B10.BR (H-2k, minor-histoincompatible) mice. Blood counts, BM colonies in agar, and various immune functions of spleen cells from the recipient mice were tested 2-12 weeks post-BMT and compared with those of normal donors. The following observations were made: (A) Peripheral blood lymphocyte counts decreased to 30% of normal 2 weeks post-BMT with almost normal recovery at 8 weeks. (B) The percentage of Thy1.2+ splenocytes reached normal levels at 8 weeks post-BMT. (C) The number of BM colonies (GM-CFU) was reduced to 10% at 2 weeks and fully recovered at 12 weeks. (D) Proliferative response to the B-cell mitogen LPS was fully reconstituted after 4 weeks; however, anti-SRBC PFC (following Mishell-Dutton cultures) was restored 50% at 8-12 weeks. (E) Reconstitution of T cell functions including proliferative responses to concanavalin A, phytohemagglutinin, and allogeneic leukocytes, and allocytotoxicity, did not exceed 50% even 12 weeks post-BMT. Overall, depletion of T cells from donor BM allografts incompatible at minor histocompatibility loci, did not seem to significantly alter the rate of immunohematopoietic reconstitution in the lethally irradiated BM recipients.

Alloantigen persistence in induction and maintenance of transplantation tolerance

Infusion of parental bone marrow cells into F1 hybrids conditioned by total lymphoid irradiation (TLI) results in chimeras with a high percentage of donor-type cells, and without clinical signs of graft-vs.-host reaction. In these chimeras, a state of tolerance has been shown to be associated with paucity of cytotoxic T lymphocyte percursors (pCTL) reactive with host-type alloantigens. To determine whether the presence of tolerizing alloantigens is essential for maintenance of unresponsiveness, lymphohematopoietic cells obtained from such tolerant chimeras were transferred into supralethally irradiated recipients of two different genotypes: in one case the adoptive recipients were syngeneic with host-type cells, and in the other they were syngeneic with donor-type cells of the original chimeras, thus providing the chimeric cells with a tolerogen-free environment. After "parking" for 4 d in syngeneic donor-type mice, the transferred cells displayed a marked increase in the frequency of pCTL directed against tolerizing alloantigens, whereas a low pCTL frequency directed against the same H-2 target cells was maintained in allogeneic tolerizing-type adoptive recipients. Multiple injections of adoptive donor-type mice with tolerizing-type cells of the original chimera reestablished a low level of cytotoxic precursors. Cytotoxic activity against unrelated alloantigens was independent of the presence of tolerogen-presenting cells in the adoptively transferred mice. Our experimental model suggests that persistence of cells bearing tolerizing alloantigens is an essential requirement for maintenance of previously established tolerance.

Bone marrow transplantation with T-cell-depleted grafts. I. Reconstitution of immunohemopoietic functions in lethally irradiated mice transplanted with unseparated or T-cell-depleted syngeneic bone marrow grafts

The potential role of donor's mature T lymphocytes on the recovery of various immunological functions and hematopoiesis was investigated in lethally irradiated BALB/c mice by studying reconstitution with normal, as compared with T-cell-depleted, syngeneic marrow grafts. Recovery of total, as well as mononuclear, peripheral white blood cell counts, platelets, hemoglobin levels, proportion of Thy 1.2+ cells, responses to concanavalin A, phytohemagglutinin and lipopolysaccharide, mixed lymphocyte response, cell-mediated lympholysis response, anti-SRBC agglutinins and natural killer activity were basically similar in recipients of unmanipulated (as compared with T cell depleted) syngeneic marrow grafts. The data suggest that in a syngeneic murine bone marrow transplantation setting, mature donor T lymphocytes do not seem to play a major role in immunohemopoiesis. Normal T cell number and T-cell-dependent immune function can be readily regenerated out of the stem cell reservoir of adult donors following transplantation into lethally ablated recipients.

Functional clonal deletion versus active suppression in transplantation tolerance induced by total-lymphoid irradiation

Transplantation tolerance and stable chimerism were established in adult mice conditioned with a short course of total-lymphoid irradiation (TLI) followed by infusion of 30 X 10(6) allogeneic bone marrow cells. Spleen cells of tolerant mice could not exert a proliferative or cytotoxic response against host-type cells in vitro and were unable to induce graft-versus-host reaction in secondary host-type recipients. The degree of suppression assessed by coculturing tolerant splenocytes in vitro in the one-way mixed lymphocyte reaction was quite variable--and, in some cases, was not at all demonstrable, although tolerance was clearly maintained. Suppression, when apparent, could not be ascribed to T lymphocytes. Suppressor cells were found to bind soybean agglutinin and could be separated from the nonsuppressive cells by means of this lectin. Dissociation of the suppressive population (SBA+ cells) from that which is normally alloreactive (SBA- cells) resulted in a suppressor cell-depleted fraction that was still unable to respond to host-type cells but regained reactivity to unrelated cells. Limiting dilution analysis of chimeric splenocytes revealed markedly reduced frequencies of cytotoxic T lymphocyte precursors (CTL-P) directed against host-type cells, as compared with normal splenocytes reacting against the same target cells. This difference was accentuated when these cells were sensitized to host-type target cells prior to plating in limiting dilution cultures. In 1:1 mixing experiments of normal and chimeric splenocytes, there was no evidence of any in vitro suppressive activity to account for hyporeactivity of chimeric cells against host-type cells. Thus, maintenance of TLI-induced tolerance seemed not to be mediated primarily through an active suppressor cell mechanism.

In vitro elicitation of cytotoxic response against a nonimmunogenic murine tumor by allosensitization

The murine lymphoma (thymoma) PIR-2 of C57BL/6 origin, primarily induced in our laboratory by fractionated X-ray irradiation, has been shown to be nonimmunogenic by its failure to immunize syngeneic mice in vivo or to evoke a cytotoxic response in primary mixed lymphocyte-tumor cell cultures (MLTC) in vitro. We were able, however, to demonstrate the existence of anti-PIR-2 cytotoxic cells among allogeneic-primed C57BL/6 responding lymphocytes using the technique of limiting dilution cultures (LDC). The frequency of anti-PIR-2 cytotoxic cells among C57BL/6 lymphocytes sensitized against BALB/c splenocytes in mixed leukocyte culture (MLC) was 1/20 to 1/40, and the cytotoxic activity of positive LDC wells against PIR-2 reached 60% as determined by a 4-h 51Cr-release assay. The frequency of anti-PIR-2 cytotoxic cells could be increased two- to 10-fold (up to 1/4) by removing nylon-wool-adherent cells from the primed cell population and/or by enriching the primed lymphoblast population on a Percoll density gradient. Anti-PIR-2 cytotoxic cells were found to be Thy1+; Lyt1-2+ cells. Clones isolated from the LDC wells manifested strong cytotoxic activity toward PIR-2 cells and the stimulating BALB/c splenocytes but not against other H-2b tumor lines or C57BL/6 splenocytes. We suggest that the procedure of allostimulation in MLC-LDC is an effective in vitro means of generating highly reactive cytotoxic cells against poorly immunogenic neoplasms.

Studies on the immune response to fixed antigens. IV. Recall of immunologic memory with fixed antigens

The chemically modified antigens, trinitrophenylated sheep red blood cells (SRBC) and glutaraldehyde-SRBC, elicited specific secondary responses in mice but were unable to induce primary responses. They also induced specific immunologic memory. The secondary immune response was directed to the specific determinants of SRBC but not to new antigenic determinants created by the chemical modification process. The interpretation of these findings is discussed in relationship to the ability of fixed antigens to be processed by macrophages.

Studies on the Immune Response to Fixed Antigens

Heavy trinitrophenylated sheep red cells (TNP 128SRC) and glutaraldehyde-treated SRC (G-SRC) could not induce cellular cytotoxicity against 51Cr-SRC. In contrast, the native antigen SRC could stimulate a cytolytic response against the radiolabeled homologous target cell. However, fixed SRC could stimulate a priming function that accelerated and augmented the secondary cytotoxic response to SRC. Such fixed antigens could stimulate a delayed-type hypersensitivity (DTHS) response also. Thus, the immunologic memory to the chemically modified antigen, as well as the DTHS response, are completely dissociated from the primary cytotoxic responses.

The primary and the secondary cytotoxic responses that were developed in the spleens of the injected mice were mediated by antibody-dependent cellular cytotoxicity (ADCC), since the active supernatant that was released from the spleen cells could lyse the target cells in the presence of normal splenocytes. The active supernatant was identified as antibody. We suggest that B effector cells cytolyzed the antibody-coated target cells. Normal cells from nude mice could mediate the cytolytic process as efficiently as spleen cells from other strains of mouse. The results are discussed in terms of selective stimulation of T cell subpopulations.

Studies on the immune response to fixed antigens. III. Induction of helper function for antibody-dependent cellular cytotoxicity responses

Heavy trinitrophenylated sheep red cells (TNP128SRC) and glutaraldehyde-treated SRC (G-SRC) could not induce cellular cytotoxicity against 51Cr-SRC. In contrast, the native antigen SRC could stimulate a cytolytic response against the radiolabeled homologous target cell. However, fixed SRC could stimulate a priming function that accelerated and augmented the secondary cytotoxic response to SRC. Such fixed antigens could stimulate a delayed-type hypersensitivity (DTHS) response also. Thus, the immunologic memory to the chemically modified antigen, as well as the DTHS response, are completely dissociated from the primary cytotoxic responses. The primary and the secondary cytotoxic responses that were developed in the spleens of the injected mice were mediated by antibody-dependent cellular cytotoxicity (ADCC), since the active supernatant that was released from the spleen cells could lyse the target cells in the presence of normal splenocytes. The active supernatant was identified as antibody. We suggest that B effector cells cytolyzed the antibody-coated target cells. Normal cells from nude mice could mediate the cytolytic process as efficiently as spleen cells from other strains of mouse. The results are discussed in terms of selective stimulation of T cell subpopulations.

Cellular assay for measuring anti-erythrocyte antibody responses

Splenocytes from mice immunized with sheep red cells (SRC) or donkey red cells (DRC) were able to lyse radiolabeled SRC or DRC respectively. The cytotoxic effect was mediated by the active supernatant which was released from the immune splenocytes and which was characterized as antibody. This cellular cytotoxic response was found to be a very reliable, efficient, rapid and objective assay for measuring anti-erythrocyte antibody responses.

The hyperglycemic effect of 1-deoxy-D-manno-heptulose. Inhibition of hexokinase, glucokinase, and insulin release in vitro

Injection of 1-deoxy-D-manno-heptulose (1-DMH, 400 mg, subcutaneously) into rats is associated with a hyperglycemia which reaches a peak after 2 h and is about half that caused by the same dose of D-manno-heptulose (MH). Insulin release from pieces of rabbit pancreas suspended in 15 mM glucose and 20 mM 1-DMH was about 20% of the release in the absence of 1-DMH. Under the same conditions MH caused a complete block of insulin release. Yeast hexokinase was inhibited to the extent of 58% and 68% by 1-DMH and MH (14.3 mM), respectively. 1-DMH is also inferior to MH as an inhibitor of crude rat liver hexokinase and glucokinase. The primary hydroxyl group on carbon-1 of MH is not required for the heptulose to exert its inhibitory effect on hexokinase.