The molecular mechanism of costimulatory signal for T cell activation

The initiation of T cell responses against antigens requires two distinct signals. The first, the essential signal is the engagement of T cell receptor to antigen peptide in the context of MHC molecules on antigen presenting cells (APC). The presence of the second signal (costimulatory signal) determines whether responding T cells to be fully responsive or to be anergic (antigen specific nonresponsiveness). There are numbers of such costimulatory receptor/ligand pairs including B7/CD28: CTLA4, VCAM-1/VLA4, ICAM-1/LFA-1, HSA/unknown, and LFA-3/CD2. Among those ligand receptor pairs, B7/CD28 pathway is chosen and the molecular mechanism how T cell responses are regulated by B7/CD28 is discussed.     

Differential expression of costimulatory molecules in chronic inflammatory periodontal disease tissue

OBJECTIVES: To present the technique of the extended subcranial approach to the anterior skull base and to review the results in 55 patients who underwent the procedure. STUDY DESIGN: Retrospective review of the records of 55 patients who underwent the extended subcranial approach to the anterior skull base between 1994 and 1998 for the treatment of various neoplasms originating in the nasal cavity, nasopharynx, paranasal sinuses, orbit, or meninges, as well as for the repair of complex craniofacial trauma and/or cerebrospinal fluid (CSF) leak. Preoperative patient evaluation and the surgical technique are also reviewed. METHODS: Patient records were retrospectively reviewed and tabulated for age, sex, and indications for procedure, with special focus on early outcome and complications. RESULTS: Twenty-six patients underwent oncologic resections, 22 patients had reduction of complex fronto-naso-orbital and skull base fractures, and seven patients had repair of CSF leak. Significant complications in the oncologic group consisted of one hematoma requiring needle aspiration and two cases of temporary nontension pneumocephalus. In the fracture group, one patient died because of extensive intracerebral damage and multiorgan failure, and one patient had nontension pneumocephalus coupled with CSF leakage and one patient had temporary nontension pneumocephalus. The most common late complication in all three groups was anosmia. CONCLUSIONS: Based on their review, the authors conclude that the extended subcranial approach to the anterior skull base is a safe, versatile, and effective procedure for the surgical treatment of various pathological conditions involving the anterior skull base.     

The function of costimulatory molecules and the development of IL-4-producing T cells

In the observation of various opportunistic pathogens in HIV-positive persons, co-infection by Cryptococcus neoformans together with Mycobacterium avium intracellulare was found if there was a CD4 lymphocyte count as low as 3-20/microliters. In 1540 HIV-positive patients under treatment at a Berlin hospital (Auguste-Viktoria-Krankenhaus) during 1985-1994, all AIDS-relevant diseases were examined in a multivariate analysis as variables of influence on the manifestation of a systemic Mycobacterium avium complex (MAC) infection. The analysis involved data on 36 cases of cryptococcosis and 202 cases with a typical clinical course in whom MAC had been detected at sterile body sites. As significant and independent factors of influence, the following were identified: C. neoformans infection, wasting syndrome, lower age, low CD4 lymphocyte count and preceding Pneumocystis carinii pneumonia (PcP) prophylaxis. Cryptococcosis ranged first with an ods ratio of 2.75. The concomitant manifestation of cryptococcosis and systemic MAC infection in six patients is shown. Because both opportunists, C. neoformans and avian mycobacteria, may have their common habitat in droppings of defined species of pet birds, a common source of infection deserves further clinical and epidemiological attention.     

Mechanisms of multiple myeloma cell growth

The mechanism of human multiple myeloma cell growth was studied utilizing eleven myeloma cell lines established in vitro or in vivo (Scid mouse). Four bone marrow derived cell lines grew dependently on IL-6 or bone marrow stromal cells. Seven extramedullary lesion derived cell lines grew spontaneously and additively proliferated in response to IL-6. All cell lines expressed the IL-6 receptor (IL-6R) and IL-6RmRNA, but none expressed IL-6mRNA. No IL-6 activity was detected in the myeloma cell culture supernatant. Both the anti-IL-6 antibody and anti-IL-6R antibody neutralized IL-6-induced proliferation, but did not inhibit spontaneous proliferation of extramedullary lesion derived cell lines. While establishing cell lines, it was found that the proliferating fraction was primarily included in a fraction which was non-adherent to stromal cells and composed of undifferentiated plasmablasts. Undifferentiated plasmablasts proliferated in response to IL-6, in contrast to the adherent, mature form of myeloma cells which did not proliferate in response to IL-6. Innoculation of myeloma cells into Scid mice induced subcutaneous tumor formation. These tumors were composed of undifferentiated plasmablasts, which also proliferated in response to IL-6. These results imply that the growth of bone marrow derived myeloma cell lines are dependent on the IL-6 paracrine mechanism and that the growth of extramedullary lesion derived cell lines primarily autonomous and additively dependent on the IL-6 paracrine mechanism.     

Expression of adhesion molecules and costimulatory molecules in inflammatory myopathies

To clarify the local immune responses in inflammatory myopathies, we examine recent studies on expression of adhesion and costimulatory molecules. Adhesion molecules participate in MNC influx from blood vessels into muscle tissues and interactions of inflamed muscle cells with surrounded MNC. These antigens may work as costimulatory molecules in antigen presenting process by muscle cells, as well as in augmentation of inflammation by infiltrating MNCs.     

Increased expression of costimulatory molecules on peripheral blood monocytes in patients with Crohn's disease

BACKGROUND: Activation of T lymphocytes and monocytes/macrophages has been implicated in the pathogenesis of Crohn's disease (CD). Costimulatory molecules play important roles in optimal T-cell activation. METHODS: With flow cytometric analysis we have investigated the expression of the costimulatory molecules B7-1 (CD80), B7-2 (CD86), and CD18 and the intercellular adhesion molecule-1 (ICAM-1) on peripheral blood monocytes and the expression of the activation markers HLA-DR and IL-2R (CD25) on peripheral blood T lymphocytes from 31 CD patients, 17 ulcerative colitis (UC) patients, and 10 healthy controls. RESULTS: In CD patients the percentage of activated T cells (CD3+ HLA-DR+ and CD3+ IL-2R+) was significantly increased compared with those of controls and UC patients (P < 0.05). Most monocytes from all three groups expressed B7-2, CD18, and ICAM-1 molecules (all > 79%), but only a few positive cells expressed B7-1 molecules (< 5%). No significant differences were detected in the percentage positivity of all costimulatory molecules tested among CD, UC, and controls. The mean fluorescence intensity (MFI) of B7-1 in all three groups was very weak and not significantly different. However, in CD patients there was a significantly increased MFI of B7-2, CD18, and ICAM-1 molecules compared with UC and controls (P < 0.05). On the other hand, both the percentage positivity and MFI of HLA-DR molecules on monocytes of UC patients were significantly lower than those of CD patients and controls (P < 0.05). CONCLUSIONS: Expression of the costimulatory molecules B7-2, CD18, and ICAM-1 on peripheral blood monocytes of CD patients is increased. In CD patients activation of peripheral T lymphocytes may correlate with increased expression of these costimulatory molecules on peripheral blood monocytes.     

Allogeneic stem cell transplantation for multiple myeloma

Ethanol is added to unleaded gasoline as an oxygenate to decrease carbon monoxide automobile emissions. This introduces inhalation as a new possible route of environmental exposure to humans. Knowledge of the pharmacokinetics of inhaled ethanol is critical for adequately assessing the dosimetry of this chemical in humans. The purpose of this study was to characterize the pharmacokinetics of inhaled ethanol in male and female B6C3F1 mice and F344 rats and to develop a physiologically based pharmacokinetic (PBPK) model for inhaled ethanol in mice, rats, and humans. During exposure to 600 ppm for 6 hr, steady-state blood ethanol concentrations (BEC) were reached within 30 min in rats and within 5 min in mice. Maximum BEC ranged from 71 microM in rats to 105 microM in mice. Exposure to 200 ppm ethanol for 30 min resulted in peak BEC of approximately 25 microM in mice and approximately 15 microM in rats. Peak BEC of about 10 microM were measured following exposure to 50 ppm in female rats and male and female mice, while blood ethanol was undetectable in male rats. No sex-dependent differences in peak BEC at any exposure level were observed. Species-dependent differences were found following exposure to 200 and 600 ppm. A blood flow limited PBPK model for ethanol inhalation was developed in mice, rats, and humans which accounted for a fractional absorption of ethanol. Compartments for the model included the pulmonary blood and air, brain, liver, fat, and rapidly perfused and slowly perfused tissues. The PBPK model accurately simulated BEC in rats and mice at all exposure levels, as well as BEC reported in human males in previously published studies. Simulated peak BEC in human males following exposure to 50 and 600 ppm ranged from 7 to 23 microM and 86 and 293 microM, respectively. These results illustrate that inhalation of ethanol at or above the concentrations expected to occur upon refueling results in minimal BEC and are unlikely to result in toxicity.     

Homing behaviour of the malignant cell clone in multiple myeloma

Multiple myeloma (MM) represents a B cell malignancy characterised by the presence of a monoclonal population of end-stage B cells in the bone marrow. Although fully matured bone marrow plasma cells are the predominant cell type in MM, there is much evidence that also more immature B cells are included in the malignant cell clone which are considered to be the myeloma precursor cells. The fact that these cells are detectable in the blood circulation and that their number increases with disease progression, makes it very likely that they represent the component of the tumour clone that mediates disease dissemination. This implies that these cells must have the potential to extravasate and home to the bone marrow environment. Like the migration mechanisms used by normal leukocytes and/or metastatic tumour cells of non-haematopoietic origin, it can be assumed that this bone marrow homing process is mediated by adhesive interactions and chemotactic signals provided by the microenvironment of the tumour. Once in the bone marrow compartment, myeloma cells will receive the appropriate signals to grow and survive. This aspect of tumour-homing is found to be the result of a functional interplay between the myeloma cells and the surrounding microenvironment, involving the action of several cytokines and adhesion molecules. In the end phase of the disease, myeloma cells can lose their stroma-dependency resulting in extramedullary tumour growth. We review normal B cell homing and discuss molecular mechanisms that determine the homing behaviour of the malignant cell clone in MM.     

Characterization of p16(INK4A) expression in multiple myeloma and plasma cell leukemia

Loss of p16(INK4A) (p16) expression is frequently associated with the development of epithelial and lymphoid malignancies. However, the frequency and significance of p16 abnormalities in multiple myeloma (MM) and the more aggressive phase of plasma cell leukemia (PCL) have not been well defined. Accordingly, the goal of this study was to define the expression and function of p16 in fresh samples of MM and PCL. We found that p16 protein was highly expressed in primary MM cells, although it was undetectable in fresh samples of PCL. Additionally, p16 protein was also absent in four of four MM-derived cell lines. To determine the mechanism for p16 underexpression in PCL and MM-derived cell lines, we performed PCR analysis to evaluate both gene deletion and the presence of methylation. Interestingly, the p16 gene was present and methylated in all patient PCL cells and MM cell lines, whereas it was unmethylated in patient MM cells and normal B cells. Furthermore, treatment with the demethylating agent 5-deoxyazacytidine or p16 retrofection restored p16 protein expression and induced G1 growth arrest in patient PCL cells and MM cell lines. These results suggest that inactivation of the p16 gene by methylation may be associated with decreased growth control and the development of PCL in a subset of patients with MM.     

Long-term T cell memory requires the surface expression of self-peptide/major histocompatibility complex molecules

How memory T cells are maintained in vivo is poorly understood. To address this problem, a male-specific peptide (H-Y) was identified and used to activate female anti-H-Y T cells in vitro. Anti-H-Y T cells survived in vivo for at least 70 days in the absence of antigen. This persistence was not because of the intrinsic ability of memory T cells to survive in vivo. Instead, the survival and function of adoptively transferred memory cells was found to require transporter of antigen protein 1-dependent expression of self-peptide/major histocompatibility complex class I molecules in recipient animals. Therefore, it appears that the level of T cell receptor engagement provided by transporter of antigen protein 1-dependent, self-peptide/major histocompatibility complexes is sufficient to maintain the long-term survival and functional phenotype of memory cells in the absence of persistent antigen. These data suggest that positive selection plays a role not only in T cell development but also in the maintenance of T cell memory.     

Nitrosoureas in multiple myeloma

A number of cooperative-group and single-institution studies have shown that BCNU used in combination with prednisone alone or with melphalan,cyclophosphamide, and prednisone is useful for remission induction in patients with previously untreated multiple myeloma. In this setting, results with BCNU (and probably CCNU) are as good as (but not superior to)the results obtained to the frequency of remission induction, duration of remission, and survival. BCNU plus prednisone also appears to be equal to melphalan plus prednisone for remission-maintenance therapy, although it is still unclear whether maintenance therapy is superior to discontinuation of therapy during remission. At the present time, the major use of the nitrosoureas in multiple myeloma appears to be for patients who enter remission with conventional alkylating-agent therapy and later relapse. BCNU and CCNU are occasionally effective when used as single agents or in combination with other alkylating agents for relapsing patients. Results of a pilot study at the University of Arizona with low doses of BCNU and adriamycin for patients relapsing on alkylating-agent therapy have been encouraging, with a 54% (seven of 13 patients) incidence of CRs and PRs. The use of this combination in conjunction with vincristine and prednisone for relapsing patients is under investigation by the Southwest Oncology Group.     

Dynamic expression changes in vivo of adhesion and costimulatory molecules determine load and pattern of lymphoma liver metastasis

Although intradermal primary tumor growth and spontaneous liver metastasis of ESbL-lacZ lymphoma in syngeneic DBA/2 mice are progressive and malignant, they are characterized by a transient plateau period with a constant tumor diameter and a low number of metastasized cells in the liver. This period, which was shown to be immune dependent, was followed by a second expansion phase characterized by a preferential localization of tumor cells in the periportal areas of liver lobules (mosaic phenotype). To elucidate possible mechanisms leading to the plateau period as well as for the mosaic-like metastasis pattern, we investigated, using flow cytometry analysis, alterations in costimulatory and adhesion molecule expression in liver sinusoidal cells as well as in tumor cells isolated directly ex vivo throughout the kinetics of metastasis. In tumor and sinusoidal cells, we found up-regulation in the expression of MHC class II and B7 molecules during the plateau period. These molecules, which facilitate cell-mediated immune responses, were again down-regulated during the final exponential tumor growth and metastasis. In the final expansion phase, in which the mosaic phenotype of liver metastasis is seen, we detected a significant increase of leukocyte function-associated antigen-1/intercellular adhesion molecule-1 expression in both tumor and sinusoidal cells, suggesting tumor cell-sinusoidal cell interactions. vascular cell adhesion molecule-1/very late activated antigen-4 did not show any modification during the whole metastatic process. In vivo application of monoclonal antibodies directed to leukocyte function-associated antigen-1 and intercellular adhesion molecule-1 appeared to block the spread of metastasis, while no effect was seen with monoclonal antibodies directed to vascular cell adhesion molecule-1 and very late activated antigen-4. This study reveals in situ expression changes of cell surface molecules in tumor and host cells during metastasis. The changes seen during the plateau phase and during the second expansion phase differ, suggesting associations with mechanisms of immune control and tumor immune evasion, respectively.     

Effects of liposome-encapsulated hemoglobin on phorbol ester-induced superoxide production and expression of costimulatory molecules by monocytes in vitro

The effects of Neo Red Cell (NRC), a liposome-encapsulated hemoglobin (LEH), on the phorbol ester-induced superoxide production and the expression of costimulatory molecules by human peripheral monocytes were investigated. The treatment of human mononuclear cells with NRC caused the potentiation of superoxide production in response to PMA. The longer incubation (20 h) resulted in a decrease in the PMA-induced superoxide production, which was in parallel to a decrease in the viability of the monocytes. A flow cytometric analysis showed that a slight expression of CD80 (B7-1) on monocytes was induced by NRC treatment, whereas the constitutive expressions of CD86 (B7-2) and CD54 (ICAM-1) were unchanged. The activation of monocytes with interferon-gamma (IFN-gamma) induced the expressions of CD80, CD86, and CD54 under all conditions tested, but NRC treatment tended to decrease the IFN-gamma-induced expression of CD54 on monocytes. These results suggest that the administration of LEH may modify the functions of human monocytes.     

CRF stimulates expression of multiple fos and jun related genes in the AtT-20 corticotroph cell

Pretreatment of DBA/2 mice (n = 14-15 per group) with an 18-mer antisense probe to the NMDA-receptor submit NR1 (2 x 1 micrograms, or 2 x 83 pmol, NR1 antisense probe intracerebroventricularly, -29 and -7 h before testing for seizure response) resulted in almost complete suppression of sound-induced clonic seizures. A saline-treated group gave a 100% seizures response, while the group treated with NR1 antisense probe gave a 7% seizure response to the sound stimulus. The group treated with NR1 nonsense-probe showed no anticonvulsant protection (93% seizure response). The anticonvulsant protection observed following NR1 antisense administration was of relatively short duration, with seizure response gradually returning to control levels 12 to 24 h following the termination of antisense administration. When NR1 receptor levels were assessed by receptor autoradiography ([3H]-MK 801 and -CGP 39653 binding) in the same groups of mice, significant (20%) reductions in NR1 levels were observed in the retrosplenial cortex and the overall cortex. The seizure-induced expression of c-fos and NGFI-A in thalamus, hypothalamus, inferior colliculus and medical geniculate seen in vehicle- and NR1 nonsense-treated mice was completely blocked by NR1 antisense pretreatment.     

Imaging of multiple myeloma

Multiple myeloma (MM) is characterized by a proliferation of plasma cells responsible for osteolytic lesions. Imaging studies are performed in MM to establish diagnosis and prognosis, and may also be used to judge the efficacy of treatment and to detect complications. TO ESTABLISH THE DIAGNOSIS: Conventional radiography demonstrates, at the time of diagnosis, characteristic features in 80% of cases. These lytic lesions involve more often the sites of red marrow. More rarely the only abnormal finding is diffuse osteopenia. Tomodensitometry and, above all, magnetic resonance imaging (MRI), which is a reference method for bone marrow disorders, can be useful for diagnosis in some difficult cases. But the lesions observed, hyposignals on spin echo T1 sequences and hyposignals on T2-weighted gradient echo, are not specific and usually do not allow to distinguish MM from osteolytic metastasis or other bone marrow disorders. TO DETERMINE EXTENT OF DISEASE AND TO EVALUATE PROGNOSIS: According to Durie and Salmon, the extension of home lesions at diagnosis is strongly correlated with the myelomatous measured cellular mass and with survival of patients. But this relation is denied by some authors who have noted that the shortest survival was seen in patients with normal X-rays. TO JUDGE THE EFFICACY OF TREATMENT: Improvement of the radiological abnormalities is observed in nearly 30% of patients responding to a conventional chemotherapy and appears to be an adverse pronostic sign. A good correlation between MRI and the biological response to treatment has also been reported. TO RECOGNIZE COMPLICATIONS OF DISEASE: Conventional radiography is also very important in diagnosis of complications like fractures or vertebral compression. Lastly, MRI is the investigation of first choice in the evaluation of patients with suspected spinal cord compression.     

Immunochemical studies in multiple myeloma

Many hospitals are converting to electronic records and allied health professionals are required to modify their traditional documentation practices to accommodate this new technology. This paper discusses a study conducted to determine the computer anxiety and attitudes of physical, occupational, and speech therapists in a large urban teaching hospital before and after the implementation of a computerized documentation system. Fifty-three therapists surveyed with a preinstallation questionnaire reported mild computer anxiety and generally good attitudes about the planned computer system. A greater amount of previous computer use and better self-related computer skills were consistent with less computer anxiety. Seven of the original sample became the first to use the computer system. After their six month trial period, surveys revealed a reduction in computer anxieties. Manual time logs completed before and after the system implementation revealed a significant decrease in total documentation time when using computers.     

Glomerular lesions in multiple myeloma

An autopsy case of multiple myeloma (IgG, lambda type), clinically characterized by decreased glomerular filtration rate, is reported with particular emphasis on changes in the glomeruli of kidneys. Histologically, the glomeruli revealed slight increase in mesangial matrix and focal thickening of tuft capillary wall. Electron-microscopically, deposits were observed in a subendothelial location in the glomerular capillary walls, and inclusions were noted in the cytoplasm of the visceral epithelial cells. Histoimmunofluorescent study of the kidney demonstrated intense focal and slight diffuse positivity against labelled antisera of anti-IgG and anti-lambda type of light chain on the capillary wall of the glomerular tufts. Other immunoglobulins were not demonstrable in capillary walls. These findings represent the intraglomerular deposition of paraprotein of multiple myeloma without amyloidosis.