Tolerance to p53 by A2.1-restricted cytotoxic T lymphocytes

Elevated levels of the p53 protein occur in approximately 50% of human malignancies, which makes it an excellent target for a broad-spectrum T cell immunotherapy of cancer. A major barrier to the design of p53-specific immunotherapeutics and vaccines, however, is the possibility that T cells may be tolerant of antigens derived from wild-type p53 due to its low level of expression in normal thymus and lymphohemopoetic cells. The combination of p53 deficient (p53-/-) and p53+/+ HLA-A2.1/Kb transgenic mice was used as a model to explore the possibility that A2.1-restricted cytotoxic T lymphocytes (CTL) are functionally tolerant of self peptides derived from the wild-type p53 tumor suppressor protein. A2.1-restricted CTL specific for a naturally processed p53 self-epitope spanning residues 187-197 were completely aborted in p53+/+ as opposed to p53-/- transgenic mice. In contrast, CTL specific for a second self-epitope spanning residues 261-269 of the murine p53 sequence were detected in both p53-/- and p53+/+ A2.1/Kb transgenic mice. However, the avidity of the CTL effectors obtained from p53+/+ mice was 10-fold lower than that obtained from p53-/- mice, again suggesting elimination of CTL with high avidity for the A2.1-peptide complex. The circumvention of functional tolerance of high avidity CTL may therefore be a necessary prerequisite for optimizing immunotherapy against A2.1-restricted wild-type p53 epitopes in humans.

Hepatic dysfunction following busulfan and cyclophosphamide myeloablation: a retrospective, multicenter analysis

Veno-occlusive disease continues to be a significant cause of morbidity and early mortality following bone marrow transplantation. This study retrospectively analyzes the incidence and risk factors for severe VOD in 350 patients treated with 4 days of busulfan (total 16 mg/kg) and 2 days of cyclophosphamide (120 mg/kg) at four marrow transplant centers. Using the criteria defined by McDonald et al (Hepatology 1984; 4: 116-122), 93/350 (27%) developed VOD (11% mild, 5% moderate and 11% severe). Multivariate analysis revealed the following risk factors to be significantly associated with severe VOD: pretransplant transaminase and alkaline phosphatase elevation, ciprofloxacin antibiotic prophylaxis, use of estrogen/progestins or vancomycin during the peritransplant period and methotrexate for GVHD prophylaxis. Mild to moderate grades of VOD were not associated with significantly increased mortality but mortality was higher in patients with severe VOD (31%, P = 0.0013). These data suggest that risk factors for VOD may depend on the preparative regimen used and suggest that use of these risk factors may identify a subgroup of patients that can be targetted for studies of prevention of VOD.

Targeting p53 as a general tumor antigen

A major barrier to the design of immunotherapeutics and vaccines for cancer is the idiosyncratic nature of many tumor antigens and the possibility that T cells may be tolerant of broadly distributed antigens. We have devised an experimental strategy that exploits species differences in protein sequences to circumvent tolerance of high-affinity T cells. HLA transgenic mice were used to obtain cytotoxic T lymphocytes specific for peptides from the human p53 tumor-suppressor molecule presented in association with HLA-A2.1. Although such p53-specific cytotoxic T cells did not recognize nontransformed human cells, they were able to lyse a wide variety of human tumor cells lines, thus confirming the existence of broadly distributed determinants that may serve as targets for immunotherapy.

Inhibition of leukemic cell growth by the protein kinase C activator bryostatin 1 correlates with the dephosphorylation of cyclin-dependent kinase 2

Bryostatin 1 is a natural antineoplastic agent that activates protein kinase C. Treatment of U937 human leukemic cells with bryostatin 1 caused a 60% reduction in cell growth, whereas another protein kinase C activator, phorbol myristate acetate (PMA), completely inhibited U937 cell growth. Both bryostatin 1 and PMA induced inhibition of cyclin-dependent kinase 2 (cdk2) activity. The first phase of cdk2 inhibition correlated with the transient induction of p21, a known inhibitor of cdk2. In contrast, the second phase of cdk2 inhibition correlated with the dephosphorylation of cdk2 on threonine-160, which must be phosphorylated for cdk2 activity. The level of growth inhibition induced by these two compounds correlated with the degree of cdk2 dephosphorylation as follows: bryostatin 1, 60%; PMA, 100%.

The human glioma pathogenesis-related protein is structurally related to plant pathogenesis-related proteins and its gene is expressed specifically in brain tumors

We report the cloning of a cDNA encoding GliPR (glioma pathogenesis-related protein), a protein that is structurally similar to plant pathogenesis-related proteins. The GLIPR gene is highly expressed in the human brain tumor, glioblastoma multiforme/astrocytoma, but neither in normal fetal or adult brain tissue, nor in other nervous system tumors. GliPR shares up to 50% amino acid (aa) homology with plant pathogenesis-related proteins, group 1, over a region that comprises almost two thirds of the protein. We speculate that there may be functional similarities between the human and plant proteins as well.

Genetic and molecular analysis of hyperplastic discs, a gene whose product is required for regulation of cell proliferation in Drosophila melanogaster imaginal discs and germ cells

The hyperplastic discs (hyd) gene (formerly called l(3)c43) is located at 85E1-10 on the third chromosome of Drosophila melanogaster. It was originally identified by a temperature-sensitive mutation that causes imaginal disc overgrowth in mutant larvae raised at a restrictive temperature. Twenty new alleles of hyperplastic discs have been recovered in gamma ray, ethyl methanesulfonate and hybrid dysgenesis screens, and the molecular lesions have been identified for several of the alleles. The null phenotype appears to be lethality at or before the second instar. Adults that can be obtained in crosses of temperature-sensitive alleles maintained at permissive temperatures are sterile with one exception and have defects in germ tissue morphology. The hyperplastic discs locus has been cloned by chromosome walking from the alpha-tubulin-2 gene and encodes a 9.5-kb messenger RNA, containing a 2897-amino-acid open reading frame. Sequence analysis of HYD reveals strong similarity to a portion of the C-terminus of poly(A) binding protein and to the RAT 100-kDa PROTEIN, whose function is unknown. Developmental Northern and Western analyses show coincident accumulation of the 9.5-kb transcript and the 280-kDa protein at all stages of development, with high levels at the embryonic and pupal stages. The 280-kDa HYD protein accumulates at decreased levels in mutant alleles and at restrictive temperatures in ts alleles. Examination of relative levels of HYD protein in mutant animals support the idea that less severe mutations are those that result in disc overgrowth, while more severe mutations result in variable disc growth phenotypes.

Conformational differences in major histocompatibility complex-peptide complexes can result in alloreactivity

Mutations within the class I major histocompatibility complex (MHC) molecule that affect a peptide binding can result in strong allogeneic responses. It is believed this reflects, in part, binding of a different set of endogenous peptides by each MHC molecule. We have examined the representation of allopeptides recognized by Kb-specific cytotoxic T lymphocytes (CTL) clones among targets that express either the Kb or the Kbm8 mutant. These class I molecules mutationally differ by several residues at the base of the peptide binding groove resulting in lack of recognition of bm8 targets by most Kb-specific CTL, and in strong mutual alloreactivity. Since these differences involve pockets in the base of the peptide binding groove that are presumed to contribute to the affinity of peptide binding, and there is evidence for differences in peptide binding by the mutant and wild type molecule, it was considered most likely that alloreactivity was due to binding of different sets of peptides by each of these molecules. Surprisingly, the allopeptides recognized by Kb-specific clones from a variety of responders, including bm8, are often found associated with both the wild type and mutant class I molecules. Although for some allopeptides the amount of peptide normally found associated with bm8 is less than that associated with Kb, reactivity could not be restored by increasing the amount of the relevant peptide. Thus, the basis for much of the alloreactivity observed in this particular mutant and wild type combination is not the presence or absence of the relevant allopeptide but rather the different conformation adapted by the peptide-MHC complex. These results allow us to conclude that strong alloreactive responses can result from T cell recognition of conformational differences between the stimulation and responder MHC molecules.

Ribozyme-mediated cleavage of the bcr/abl transcript expressed in chronic myeloid leukemia

The bcr/abl transcript is specifically expressed in the hematopoietic cells of patients with chronic myeloid leukemia (CML). The Haseloff and Gerlach model was used to design a ribozyme targeted to this transcript. When tested against a synthetic substrate covering the translocation sequence, the ribozyme exhibited site specificity and an absolute requirement for divalent metal ions. Cleavage of the normal bcr was also noted but at a reduced efficiency compared to that exhibited for the bcr/abl substrate. Importantly, cleavage of the full-length bcr/abl mRNA was achieved at physiologic temperature, demonstrating effective ribozyme-mediated cleavage.

What do inventories of students' learning processes really measure? A theoretical review and clarification

Research into student learning has been based on two main theoretical sources: information processing (IP), and contextually based work on students' approaches to learning (SAL). The cross-fertilisation has been valuable, but it has led to ambiguities and misunderstandings, evident in the recent literature, about constructs, methodology, and of particular concern here, the development and interpretation of inventories of learning/study processes. The basic issue revolves around a conception of student learning as taking place within-the-student, as IP models appear to assume, or within-the-teaching/learning-context, as the SAL tradition emphasises. It is suggested that student learning is best construed within a teaching/learning context that functions as an 'open system', a model that brings some clarity to the use and interpretation of study process inventories, and that locates their value in yielding functionally useful data to researchers, teachers, and staff developers.

Management of abusive behaviour in a hemodialysis unit

Occasionally in hemodialysis units there are situations where registered nurses are unable to assist an individual whose behaviour is abusive or escalating in that direction, and the person cannot re-establish self-control and appropriate behaviour. Such abusive behaviour may arouse concern for the physical and psychological safety or security of the nurse and that of other patients and visitors. Interdisciplinary conferences were held to develop a policy document and guidelines to aid caregivers should abusive situations occur. These were the result of collaboration between physicians, nurses, social workers, a dietician and the clinical nurse specialist from psychiatry. The policy statement and guidelines include nursing actions, physician interventions and recommendations for follow-up conferences.

Lung dose rate and interstitial pneumonitis in total body irradiation for bone marrow transplantation

The effect of dose rate to the lungs and development of interstitial pneumonitis (IP) was evaluated in 114 bone marrow transplant patients receiving fractionated total body irradiation (TBI) (1200 rads TD in 6 fractions twice daily over 3 days) as part of their pre-conditioning regimen. The tumour dose (TD) was calculated as the mean lung dose as previously described (1). A 6MV linear accelerator at a mid-line dose rate of 7.5 rads/minute was used between March 1981 and June 1985 and a Co-60 source at 5 rads/minute thereafter. This resulted in a range of dose rates to the lung of between 6.9 and 8.9 rads/minute and 2.9 and 6.5 rads/minute respectively. In the majority of patients the aetiology of IP was investigated by lung biopsy with histology and culture. There was no statistically significant difference in the incidence of IP over the two sets of dose rates. Our study suggest that the incidence of IP using fractionated TBI is not influenced by dose rates below 8.9 rads per minute.

Cytokine activity after allogeneic bone marrow transplantation. IV. Production of mRNA for IL-3 and GM-CSF by mitogen-stimulated circulating mononuclear cells

The ability of circulating mononuclear cells from recipients of HLA identical sibling marrow transplants to generate messenger (m) RNA for the haemopoietic growth factors interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) upon mitogen stimulation was investigated. The amount of IL-3 mRNA per ml of blood and IL-3 mRNA per 10(7) mononuclear cells as well as the amount of GM-CSF mRNA per ml of blood was significantly lower in transplant recipients than in normal volunteers. Lower values for mRNA expression for both IL-3 and GM-CSF were associated with the use of immunosuppressive therapy post transplant. No correlation was found between the expression of message for either cytokine, or the presence or absence of acute graft-versus-host disease at the time of testing. While there was no correlation between the quantity of GM-CSF message produced and time elapsed post transplant, IL-3 message expression increased slightly with increasing time post transplant. These defects of haemopoietic regulators constitute another parameter of impaired cellular immunity occurring after allogeneic marrow transplantation.

A human Id-like helix-loop-helix protein expressed during early development

The interaction of helix-loop-helix (HLH) proteins is known to regulate the differentiation of several different tissues, including mammalian muscle and the insect peripheral nervous system. In myoblasts, the products of myogenic HLH genes such as MyoD and ubiquitous HLH proteins such as E12 are present at constant levels throughout development. An E12 monomer and a MyoD monomer form a DNA binding heterodimer that activates muscle-specific genes. These two proteins are unable to dimerize in proliferating myoblasts because a negative regulator HLH protein, Id, is present. We now report the sequence and structure of a human HLH gene related to Id, which has been designated Id-2. Two prominent Id-2 RNA molecules of 2.5 and 1.3 kilobases were found in a number of different human normal and neoplastic tissues. We believe the larger RNA is a precursor of the 1.3-kilobase mRNA that encodes an Id-2 protein of 134 amino acids. The HLH region of the Id-2 protein is 90% homologous to that of myogenic Id, but the homology is much less extensive outside the HLH region. The Id-2 gene is highly expressed during early fetal development in several tissues, including those of the central nervous system, but is not expressed in the corresponding mature tissues. Id-2 expression is modulated in association with retinoic acid-induced ganglionic differentiation of the neuroblastoma cell line SMS-KCNR. These findings suggest that Id-2 is an inhibitor of tissue-specific gene expression, although its distinctive pattern of expression during development suggests a role different from that of Id.

A prospective randomised trial of cyclosporin and methotrexate versus cyclosporin, methotrexate and prednisolone for prevention of graft-versus-host disease after HLA-identical sibling marrow transplantation for haematological malignancy

A prospective randomised trial was performed in patients given HLA-identical sibling bone marrow transplants for haematological malignancy comparing the combination of cyclosporin and methotrexate (CM) (n = 20) with the combination of cyclosporin, methotrexate and prednisolone (CMP) (n = 21) as prophylaxis for graft-versus-host disease (GVHD). There was no significant differences between the two arms for the incidence of acute GVHD grades I-IV, acute GVHD grades II-IV, chronic GVHD, interstitial pneumonitis, relapse, survival and disease-free survival. The actuarial incidence of acute GVHD grades II-IV in the CMP group was 10% and in the CM group 15% (ns). The incidence of leukaemic relapse in good risk patients was 42% in the CMP group and 40% in the CM group (ns), although the majority of these relapses were cytogenetic relapses only in patients with chronic myeloid leukaemia. The incidence of acute GVHD grades II-IV in both arms of the current trial was significantly lower than in our previous trial comparing cyclosporin and methotrexate as single agents. Leukaemic relapse is now the principal cause of treatment failure in this patient population. We conclude that prednisolone should not be included as part of the prophylactic GVHD regime and that further improvement in therapeutic outcome is dependent upon better control of the underlying malignancy.

Prophylactic use of ganciclovir in allogeneic bone marrow transplantation: absence of clinical cytomegalovirus infection

Ganciclovir was given prophylactically to 25 patients receiving allogeneic bone marrow transplants for haematological malignancy. Patients who were seropositive for cytomegalovirus (CMV) pre-transplant were given ganciclovir both pre- and post-transplant. Those who were CMV seronegative, but who received marrow from a CMV seropositive donor, received ganciclovir post-transplant. No nonhaemopoietic toxicity was observed. Toxicity was restricted to late reversible haematological toxicity in four of the 19 evaluable patients (one thrombocytopenia, one pancytopenia, two leucopenia). No CMV interstitial pneumonitis (IP) was observed, nor were any other clinically manifest CMV infections detected. Sixteen patients remain alive at greater than 84 to greater than 518 d post-transplant. In a retrospective comparison of 152 recipients of allogeneic transplants for haematological malignancy not given prophylactic ganciclovir, and in whom either the recipient or the donor or both were CMV seropositive, the incidence of all clinically manifest CMV infections was 23% (P = 0.02) and that of CMV IP 17% (P = 0.05). If only patients in the study group and the control group receiving the same cyclosporin/short methotrexate prophylactic immune suppressive regimen, the same prophylactic acyclovir regimen and the same CMV and leucocyte-filtered blood product transfusion strategy were considered, the incidence of all clinically manifest CMV infections in the control group was 24% (P = 0.01) and that of CMV IP 13% (P = 0.07). Ganciclovir appears to reduce the incidence of CMV infections in allogeneic marrow transplant recipients even in those given immune suppressive regimens associated with adequate control of acute graft-versus-host disease.

The toxicity of busulphan and cyclophosphamide as the preparative regimen for bone marrow transplantation

The toxicity of the conditioning regimen of high dose busulphan (Bu) (16 mg/kg) and cyclophosphamide (Cy) (120 mg/kg) has been compared to cyclophosphamide (Cy) (120 mg/kg) and fractionated total body irradiation (TBI) 12-14 Gy. Since 1985, 67 patients have received conditioning of Bu and Cy for HLA-identical sibling bone marrow transplants. 166 patients have received Cy and TBI since 1981. Veno-occlusive disease of the liver occurred in 19% in the Bu-Cy group and was fatal in 1/12 cases, but only in 1.3% of Cy-TBI group (P less than 0.0005) and was fatal in 1/2. 30% of evaluable patients developed haemorrhagic cystitis in the Bu-Cy group and 14% in the Cy-TBI group (P = 0.008). A multiple logistic regression analysis demonstrated the preparative regimen as the only significant risk factor for the development of veno-occlusive disease or haemorrhagic cystitis. Interstitial pneumonia was diagnosed in 12/56 evaluable patients (21%) in the Bu-Cy group and was fatal in 75%. It occurred in 39/137 evaluable patients (28%) in the Cy-TBI group with a 54% case mortality. Within the Bu-Cy group, the incidence of veno-occlusive disease and haemorrhagic cystitis was similar in chronic myeloid leukaemia (CML) and acute leukaemia (AL) groups, but there was a significant (P = 0.003) incidence of interstitial pneumonia in the CML group 36% as compared to 7% in the AL group. Preparative regimen and age were significant risk factors in the development of interstitial pneumonia in patients with CML. A flexural and acral rash ranging from pigmentation to severe erosion was noted in the Bu-Cy group, but not in the Cy-TBI group. Thus, veno-occlusive disease, haemorrhagic cystitis and cutaneous changes were more common in patients receiving Bu-Cy. Interstitial pneumonia was more common in patients receiving Bu-Cy for CML than for AL.

In vivo administration of granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF, interleukin-1 (IL-1), and IL-4, alone and in combination, after allogeneic murine hematopoietic stem cell transplantation

BALB/c mice (H-2d) given 10 Gy total body irradiation (TBI) followed by 10(7) bone marrow (BM) and 10(6) spleen cells from C57BL/6 (H-2b) donor mice received recombinant cytokines intraperitoneally (IP) twice daily. The effect on neutrophil recovery rate, graft-v-host disease (GVHD), and survival was assessed. Four reagents were used: granulocyte-colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), interleukin-1 (IL-1) and IL-4, both alone and in combination. The most effective combination for increasing the circulating absolute neutrophil account (ANC) above the control value at day 7 posttransplant was the combination of G-CSF and IL-1 (mean ANC 2.4 +/- 1.6 x 10(9)/L as compared with control value of 0.07 +/- 0.05, P less than .02), followed by G-CSF alone (mean ANC 1.1 +/- 0.2, P less than .0001), the combination of GM-CSF plus IL-1 (mean ANC 0.8 +/- 0.3, P less than .002), and the combination of G-CSF plus GM-CSF (mean ANC 0.8 +/- 0.3, p less than .005). At day 10 posttransplant, the most effective combination in raising the ANC was the combination of G-CSF plus GM-CSF (mean ANC 7.5 +/- 2.3 as compared with control value of 3.5 +/- 1.1, P less than .01), followed by G-CSF alone (mean ANC 6.9 +/- 2.1, P less than .02). At the doses used, neither G-CSF nor GM-CSF had a deleterious effect on the incidence or severity of GVHD; indeed, GM-CSF was associated with improved survival. In contrast, IL-1 at doses greater than or equal to 100 ng twice daily caused marked early mortality, and there was a suggestion that IL-4 at doses of 500 ng twice daily resulted in increased late mortality, possibly owing to exacerbation of GVHD. This model appears to be of value for exploring the use of hematopoietic growth factors before they are used clinically in marrow allograft recipients.

A Drosophila gene that is homologous to a mammalian gene associated with tumor metastasis codes for a nucleoside diphosphate kinase

The product of the abnormal wing discs (awd) gene of Drosophila is 78% identical to the product of the nm23 gene of mammals, which is differentially expressed in certain metastatic tumors. We present evidence that the awd gene codes for a nucleoside diphosphate kinase (NDP kinase) and that this Awd/NDP kinase is microtubule associated. Neuroblasts in Drosophila larvae homozygous for a null mutation in the awd gene are arrested in metaphase, indicating that microtubule-associated Awd/NDP kinase plays a critical role in spindle microtubule polymerization.

Widespread pulmonary fibrosis as a major clinical manifestation of chronic graft-versus-host disease

A 20-year-old Chinese male given an HLA-identical sibling bone marrow transplant for severe aplastic anemia, who had previously had chronic graft-versus-host disease (GVHD) of the mouth, developed myasthenia gravis and widespread pulmonary infiltrates with cough and exertional dyspnea at day 820 post-transplant. There was nothing to suggest aspiration pneumonia. Lung histology at day 940 showed some areas of dense pulmonary fibrosis, some areas of normal parenchyma, and some areas of widening of the interstitium and a mild lymphocytic infiltrate. Evidence of infection was not found. Treatment with cyclosporin and prednisone resulted in slow partial resolution of the infiltrates over 5 months. The myasthenia gravis was controlled with pyridostigmine. In view of the association with myasthenia gravis, of the absence of infectious agents and the response to immunosuppression, we conclude that widespread pulmonary fibrosis can be a major clinical manifestation of chronic GVHD. Examination of lung tissue to distinguish this from infective interstitial pneumonitis is essential.