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1.
Clin Oncol (R Coll Radiol) ; 35(4): 269-277, 2023 04.
Article in English | MEDLINE | ID: mdl-36710153

ABSTRACT

AIMS: As the US population continues to age, oncological strategies and outcomes for soft tissue sarcomas (STSs) should continue to be examined for varying age groups. The aim of this study was analyse and compare treatment strategies and oncological outcomes for octogenarian patients with STSs. MATERIALS AND METHODS: Data from the Surveillance, Epidemiology and End Results (SEER) national database were used. Varying treatment modalities were studied when utilised for specific tumour staging with respect to the eighth edition of the American Joint Committee on Cancer. RESULTS: In total, 24 666 patients were included for analysis, where 3341 (14%) were 80 years old or older. The octogenarian group was diagnosed with more advanced disease (stages II-IV), relative to their younger counterparts (85% versus 75%, P < 0.001). However, a smaller proportion of the older patients underwent surgical resection (74% versus 86%, P < 0.001). Likewise, the octogenarians received less chemotherapy (4% versus 21%, P < 0.001) and radiotherapy (29% versus 42%, P = 0.010). Surgical resection and chemotherapy significantly improved overall survival for those older patients with stage II STS, whereas surgical resection and radiotherapy improved mortality in this cohort with both stage III and IV STS. Overall survival at 1 and 5 years of follow-up was lower within the octogenarian group compared with the younger group (1 year: 68% versus 88%, P < 0.001 and 5 years: 7% versus 58%, P < 0.001). CONCLUSIONS: Octogenarian patients, in most cases, are diagnosed with stage III or metastatic disease. Surgical resection of the primary tumour was beneficial in both age cohorts, with radiotherapy correlating to better overall survival when used in those patients with higher stage STS. Chemotherapy was associated with better mortality in the younger cohort with respect to tumour stage. The octogenarian overall survival at 1 and 5 years was lower than for younger patients.


Subject(s)
Sarcoma , Soft Tissue Neoplasms , Aged, 80 and over , Humans , Retrospective Studies , Octogenarians , Sarcoma/epidemiology , Sarcoma/therapy , Neoplasm Staging
2.
Colloids Surf B Biointerfaces ; 202: 111710, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33765626

ABSTRACT

The development of versatile carriers to deliver chemotherapeutic agents to specific targets with establishing drug release kinetics and minimum undesirable side effects is becoming a promising relevant tool in the medical field. Magnetic hybrid nanostructured lipid carriers (NLC) were prepared by incorporation of 1,8-cineole (CN, a monoterpene with antiproliferative properties) and maghemite nanoparticles (MNPs) into a hybrid matrix composed of myristyl myristate coated with chitosan. Hybrid NLC characterized by DLS and TEM confirmed the presence of positively charged spherical nanoparticles of around 250 nm diameter and +10.2 mV of Z-potential. CN encapsulation into the lipid core was greater than 75 % and effectively released in 24 h. Modification of the crystalline structure of nanoparticles after incorporation of CN and MNPs was observed by XRD, DSC, and TGA analyses. Superparamagnetic NLC behavior was verified by recording the magnetization using a vibrating scanning magnetometer. NLC resulted in more cytotoxic than free CN in HepG2 and A549 cell lines. Particularly, viability inhibition of HepG2 and A549 cells was increased from 35 % to 55 % and from 38 % to 61 %, respectively, when 8 mM CN was incorporated into the lipid NPs at 24 h. Green fluorescent-labeled NLC with DIOC18 showed an enhanced cellular uptake with chitosan-coated NLC. Besides, no cytotoxicity of the formulations in normal WI-38 cells was observed, suggesting that the developed hybrid NLC system is a safe and good potential candidate for the selective delivery and potentiation of anticancer drugs.


Subject(s)
Antineoplastic Agents , Nanoparticles , Nanostructures , Antineoplastic Agents/pharmacology , Drug Carriers , Eucalyptol , Lipids , Magnetic Phenomena , Particle Size
3.
Heliyon ; 5(1): e01170, 2019 Jan.
Article in English | MEDLINE | ID: mdl-30775570

ABSTRACT

We present a numerical study of the magnetic properties of ZnFe2O4 using Monte-Carlo simulations performed considering a Heisenberg model with antiferromagnetic couplings determined by Density Functional Theory. Our calculations predict that the magnetic susceptibility has a cusp-like peak centered at 13 K, and follows a Curie-Weiss behavior above this temperature with a high and negative Curie-Weiss temperature ( Θ C W = - 170 K). These results agree with the experimental data once extrinsic contributions that give rise to the deviation from a Curie-Weiss law are discounted. Additionally, we discuss the spin configuration of ZnFe2O4 below its ordering temperature, where the system presents a high degeneracy.

4.
Ann Oncol ; 28(4): 855-861, 2017 04 01.
Article in English | MEDLINE | ID: mdl-28119295

ABSTRACT

Background: Margetuximab is an anti-HER2 antibody that binds with elevated affinity to both the lower and higher affinity forms of CD16A, an Fc-receptor important for antibody dependent cell-mediated cytotoxicity (ADCC) against tumor cells. A Phase 1 study was initiated to evaluate the toxicity profile, maximum tolerated dose (MTD), pharmacokinetics, and antitumor activity of margetuximab in patients with HER2-overexpressing carcinomas. Patients and methods: Patients with HER2-positive breast or gastric cancer, or other carcinomas that overexpress HER2, for whom no standard therapy was available, were treated with margetuximab by intravenous infusion at doses of 0.1-6.0 mg/kg for 3 of every 4 weeks (Regimen A) or once every 3 weeks (10-18 mg/kg) (Regimen B). Results: Sixty-six patients received margetuximab (34 patients for Regimen A and 32 patients for Regimen B). The MTD was not reached for either regimen. Treatment was well-tolerated, with mostly Grade 1 and 2 toxicities consisting of constitutional symptoms such as pyrexia, nausea, anemia, diarrhea, and fatigue. Among 60 response-evaluable patients, confirmed partial responses and stable disease were observed in 7 (12%) and 30 (50%) patients, respectively; 26 (70%) of these patients had received prior HER2-targeted therapy. Tumor reductions were observed in over half (18/23, 78%) of response-evaluable patients with breast cancer including durable (>30 weeks) responders. Ex vivo analyses of patient peripheral blood mononuclear cell samples confirmed the ability of margetuximab to support enhanced ADCC compared with trastuzumab. Conclusions: Margetuximab was well-tolerated and has promising single-agent activity. Further development efforts of margetuximab as single agent and in combination with other therapeutic agents are ongoing. Trial Registration ID: NCT01148849.


Subject(s)
Antibodies, Monoclonal/administration & dosage , Antineoplastic Agents/administration & dosage , Neoplasms/drug therapy , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal/pharmacokinetics , Antibodies, Monoclonal/therapeutic use , Antibody-Dependent Cell Cytotoxicity/drug effects , Antineoplastic Agents/adverse effects , Antineoplastic Agents/pharmacokinetics , Disease-Free Survival , Dose-Response Relationship, Drug , Female , Humans , Male , Maximum Tolerated Dose , Middle Aged , Receptor, ErbB-2/biosynthesis
5.
Nanotechnology ; 24(17): 175601, 2013 May 03.
Article in English | MEDLINE | ID: mdl-23548801

ABSTRACT

A new approach to thermal decomposition of organic iron precursors is reported, which results in a simpler and more economical method to produce well crystallized γ-Fe2O3 nanoparticles (NPs) with average sizes within the 3-17 nm range. The NPs were characterized by TEM, SAED, XRD, DLS-QELS, Mössbauer spectroscopy at different temperatures, FT-IR and magnetic measurements. The obtained γ-Fe2O3 NPs are coated with oleic acid and, in a lower quantity, with oleylamine (about 1.5 nm in thickness). It was shown that changing operative variables allows us to tune the average particle diameters and obtain a very narrow or monodisperse distribution of sizes. The γ-Fe2O3 NPs behave superparamagnetically at room temperature and their magnetization saturation is reduced by about 34% in comparison with bulk maghemite. The results indicate that the distance between two neighbour NPs, generated by the coating, of about 3 nm is insufficient to inhibit interparticle magnetic interactions when the average diameter is 8.8 nm. The good quality of the NPs, obtained through the present low-cost and easy-handling process, open a new perspective for future technological applications.


Subject(s)
Magnetite Nanoparticles/chemistry , Nanotechnology/methods , Magnetite Nanoparticles/ultrastructure , Nanotechnology/economics , Particle Size , Spectroscopy, Fourier Transform Infrared , Spectroscopy, Mossbauer , Temperature
6.
J Nanosci Nanotechnol ; 9(4): 2510-7, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19437995

ABSTRACT

The influence of mechanical milling and subsequent sintering of a 2:1 molar mixture of SrCO3 and alpha-Fe2O3 on the formation of SrFeO(3-delta) pervoskite-related nanocrystalline particles is investigated. The structural evolution during the formation process is systematically investigated using X-ray diffraction, thermal analysis, X-ray photoelectron spectroscopy and Mössbauer spectroscopy. Pre-milling the mixture in air for 120 h leads to the incorporation of Sr2+ in the alpha-Fe2O3 crystal structure thus facilitating the formation of a 2:1 nanocrystalline mixture of SrFeO3 and SrFeO2.875 by sintering the pre-milled mixture in air at 800 degrees C (12 h). This temperature is approximately 300 degrees C lower than those at which SrFeO(3-delta) phases are synthesized by the conventional ceramic techniques. Pre-milling the precursors was found to result in a smaller oxygen deficiency (delta) relative to conventional ceramic synthesis of SrFeO(3-delta). Rietveld refinement of the X-ray diffraction shows the interatomic distances in the resulting SrFeO2.875 nanocrystalline phase to be slightly different from those of the conventionally prepared bulk leading, in turn, to a crystal structure with tilted polyhedral cationic sites. This structural distortion is related to both small-size and surface effects in the nanoparticles that have no counterparts in the corresponding bulk material. The surface structure of the attained SrFeO(3-delta) nanocrystalline particles shows a significant partial reduction of Fe4+ to Fe3+ due to ambient conditions and the presence of an appreciable amount of SrCO3 as well.

7.
J Synchrotron Radiat ; 16(Pt 1): 63-8, 2009 Jan.
Article in English | MEDLINE | ID: mdl-19096176

ABSTRACT

In situ Zn K-edge XANES experiments were performed to investigate the thermal evolution of the non-equilibrium state in nano-sized ZnFe2O4. The initially disordered ferrite was annealed under oxygen atmosphere and kept at temperatures of 673, 773 and 873 K. Modifications of the XANES features allowed the direct detection of the Zn local surrounding changes from Oh to Td symmetry. Quantitative analyses of these results were performed by using the principal-component analysis approach. The ferrite inversion does not change until the activation barrier is overcome at Ta = 585 K. Above Ta, the Zn ions continuously change their environment to their normal equilibrium state. Isothermal treatments confirm that the Zn transference follows a first-order kinetic process. In addition, the thermal treatment produces a partial recrystallization that increases the average grain size from 13 to 50 nm and reduces the microstrain. The room-temperature magnetic state changes from ferrimagnetic to paramagnetic, while the blocking temperature increases after the treatment.

8.
J Nanosci Nanotechnol ; 7(2): 610-7, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17450803

ABSTRACT

We report on the temperature dependencies of the Mössbauer spectra and the AC magnetic susceptibility measured in Cu-rich, FeMnCu samples prepared by mechanically alloying, using, on the one side, Cu and prealloyed FeMn powders and, on the other, pure element Cu, Mn, and Fe powders. From the correlation of the Mössbauer and susceptibility data we conclude about the basic characteristics of the phase distributions present in the different studied samples. Those distributions are a consequence of both the nanostructure induced upon milling and of the different signs of the Mn/Cu (negative) and Fe/Cu (positive) enthalpies of mixing. The proposed phase distributions are significantly different in the samples prepared from different precursors and this fact is analyzed in terms of the disproportion of the precursor FeMn alloy and in those of the favoured Mn/Cu interdiffusion and the hindered Fe/Cu one.


Subject(s)
Alloys/chemistry , Copper/chemistry , Iron/chemistry , Magnetics , Manganese/chemistry , Nanostructures/chemistry , Crystallization , Hot Temperature , Models, Chemical , Phase Transition , Powders , Spectroscopy, Mossbauer , Thermodynamics
9.
J Clin Psychol ; 57(12): 1535-42, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11745594

ABSTRACT

The present study compared personality and psychopathology profiles of veterans' wives against married women in the MMPI-2 restandardization sample. Differences in levels of distress and pathology were analyzed using the validity, clinical, and content scales of the MMPI-2. As expected, veterans' wives, when compared to restandardization wives, reported higher levels of psychopathology and distress, with symptoms such as depression, social maladjustment, and other negative, internal symptomatic behaviors. Findings are discussed in terms of the need for additional research examining this "at-risk" population.


Subject(s)
Personality Disorders/etiology , Spouses/psychology , Stress, Psychological , Veterans , Adult , Depression , Female , Humans , Middle Aged , Personality Disorders/diagnosis , Personality Inventory , Risk Factors , Social Behavior Disorders
10.
Oncology ; 61 Suppl 2: 37-42, 2001.
Article in English | MEDLINE | ID: mdl-11694786

ABSTRACT

The pivotal phase II and III Herceptin trials proved the efficacy and safety of second- or third-line single-agent Herceptin and first-line Herceptin in combination with chemotherapy, respectively. In the current trial, 114 patients were randomized to one of two dose groups of first-line Herceptin monotherapy: standard dose of 4 mg/ kg initial dose followed by 2 mg/kg intravenous (i.v.) weekly; or high dose of 8 mg/kg initial dose followed by 4 mg/kg i.v. weekly. The regimen was generally well tolerated. A similar incidence of adverse events was demonstrated in the two dose groups with the possible exception of acute infusion-related events such as fever and chills as well as rash and dyspnea, which appear to be more prevalent in the higher dose group. The overall response rate was 26% and response rates were similar between the two dose groups (24% for the standard Herceptin dose group and 28% for the high Herceptin dose group). Subgroup analysis determined a higher response rate in IHC 3+ patients (35%) and FISH-positive patients (41%). When women with stable disease for > or =6 months were included with responders, the clinical benefit rate in IHC 3+ patients was 47%. Median survival was 24.4 months, which is comparable with the survival rate seen in the pivotal phase III combination trial (25 months). Therefore, single-agent Herceptin is an important new option for the first-line treatment of HER2-positive metastatic breast cancer patients.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Antineoplastic Agents/therapeutic use , Breast Neoplasms/drug therapy , Antibodies, Monoclonal/administration & dosage , Antibodies, Monoclonal/adverse effects , Antibodies, Monoclonal, Humanized , Antineoplastic Agents/administration & dosage , Antineoplastic Agents/adverse effects , Biomarkers, Tumor/analysis , Breast Neoplasms/chemistry , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Clinical Trials, Phase II as Topic , Clinical Trials, Phase III as Topic , Combined Modality Therapy , Disease Progression , Disease-Free Survival , Female , Fever/chemically induced , Heart Diseases/chemically induced , Humans , Neoplasm Metastasis , Neoplasm Proteins/analysis , Pain/virology , Palliative Care , Randomized Controlled Trials as Topic , Receptor, ErbB-2/analysis , Receptors, Estrogen/analysis , Safety , Salvage Therapy , Survival Analysis , Trastuzumab , Treatment Outcome
11.
Eur J Cancer ; 37 Suppl 1: 25-29, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11342197

ABSTRACT

Following confirmation of the appropriate dosage, safety and potential efficacy of Herceptin(R) (trastuzumab) in small-scale phase I and II trials involving patients with refractory disease, a large trial was conducted in 222 patients with breast cancer who had relapsed after one or two chemotherapy regimens for their metastatic disease. The results showed a positive and durable overall response rate (15% according to a response evaluation committee (REC) assessment) using trastuzumab monotherapy (initial dose 4 mg/kg intravenously (i.v.) followed by 2 mg/kg i.v. weekly). In another recently completed phase II trial, 113 patients were randomised to two dose levels (initial dose of 4 mg/kg i.v. dose followed by 2 mg/kg i.v. weekly, or initial dose of 8 mg/kg followed by 4 mg/kg i.v. weekly) of single-agent trastuzumab as first-line therapy for metastatic disease. The preliminary overall response rate was 23% based on investigator assessment, and tolerability was excellent as in previous trials; efficacy was similar in both dose groups, but the side-effects tended to be more frequent in the higher dose group. The preferred dosage is therefore the same as that currently recommended, i.e. an initial dose of 4 mg/kg i.v. followed by 2 mg/kg weekly i.v. until disease progression.

12.
Leukemia ; 15(1): 128-33, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11243380

ABSTRACT

Human leukocyte antigens (HLA) class I molecules restrict the interaction between cytotoxic T cells and target cells. Abnormalities in HLA class I antigen expression and/or function may provide tumor cells with a mechanism for escaping immune surveillance and resisting T cell-based immunotherapies. The potential for applying T cell-based immunotherapy in the treatment of acute myeloid leukemia (AML) has stimulated interest in analyzing HLA class I antigen expression on leukemic blasts in this disease. Little information is available in the literature. We have analyzed HLA class I antigen expression on bone marrow samples from 25 newly diagnosed AML patients by indirect immunofluorescence staining with monoclonal antibodies. Five of these patients were also studied at relapse. Leukemic blasts were resolved from normal lymphocytes by staining with antiCD45 antibody; CD45 expression is dim on leukemia cells, but bright on lymphocytes. HLA class I antigen expression was higher on leukemic blasts than on autologous lymphocytes in all but one case. Moreover, there was no significant change in HLA class I antigen expression at relapse. These results suggest that abnormalities in HLA class I antigens are infrequent in AML and should not represent a major obstacle to the application of T cell-based immunotherapies in this disease.


Subject(s)
Histocompatibility Antigens Class I/immunology , Leukemia, Myeloid/immunology , Acute Disease , Adult , Aged , Aged, 80 and over , Female , Histocompatibility Antigens Class I/biosynthesis , Humans , Leukemia, Myeloid/pathology , Male , Middle Aged , Recurrence
13.
Eur J Cancer ; 37 Suppl 1: S25-9, 2001 Jan.
Article in English | MEDLINE | ID: mdl-11167088

ABSTRACT

Following confirmation of the appropriate dosage, safety and potential efficacy of Herceptin(trastuzumab) in small-scale phase I and II trials involving patients with refractory disease, a large trial was conducted in 222 patients with breast cancer who had relapsed after one or two chemotherapy regimens for their metastatic disease. The results showed a positive and durable overall response rate (15% according to a response evaluation committee (REC) assessment) using trastuzumab monotherapy (initial dose 4 mg/kg intravenously (i.v.) followed by 2 mg/kg i.v. weekly). In another recently completed phase II trial, 113 patients were randomised to two dose levels (initial dose of 4 mg/kg i.v. dose followed by 2 mg/kg i.v. weekly, or initial dose of 8 mg/kg followed by 4 mg/kg i.v. weekly) of single-agent trastuzumab as first-line therapy for metastatic disease. The preliminary overall response rate was 23% based on investigator assessment, and tolerability was excellent as in previous trials; efficacy was similar in both dose groups, but the side-effects tended to be more frequent in the higher dose group. The preferred dosage is therefore the same as that currently recommended, i.e. an initial dose of 4 mg/kg i.v. followed by 2 mg/kg weekly i.v. until disease progression.


Subject(s)
Antibodies, Monoclonal/therapeutic use , Antineoplastic Agents/therapeutic use , Breast Neoplasms/drug therapy , Adult , Aged , Aged, 80 and over , Antibodies, Monoclonal, Humanized , Female , Humans , Middle Aged , Multicenter Studies as Topic , Randomized Controlled Trials as Topic , Trastuzumab , Treatment Outcome
15.
Methods Cell Biol ; 64: 289-312, 2001.
Article in English | MEDLINE | ID: mdl-11070845

ABSTRACT

Each laboratory has to establish its own experience base and standard operating procedures. The intent of this discussion has been to illustrate the procedures that will lead to good flow cytometry data acquisition and analysis and to illustrate problematic areas. The most important rule of all is to recognize when there is a problem and find the correct solution. It is hoped the information provided herein will be of help in the recognition process.


Subject(s)
Flow Cytometry/instrumentation , Flow Cytometry/methods , Fluorescent Dyes , Image Processing, Computer-Assisted/methods , Leukocytes, Mononuclear/cytology , Antibodies/immunology , Antibodies/metabolism , Humans
16.
Curr Protoc Cytom ; Chapter 4: Unit 4.1, 2001 May.
Article in English | MEDLINE | ID: mdl-18770707

ABSTRACT

Flow cytometry using fluorochrome-conjugated antibodies has emerged as a major approach to automated cellular identification. One of the most important issues in immunophenotyping is using the correct amount of antibody. This unit presents techniques for ascertaining the optimal titer for individual, dual, and multiple antibodies used for simultaneous phenotyping, stressing the importance of quality control in making batches of antibody for routine use.


Subject(s)
Flow Cytometry/instrumentation , Flow Cytometry/methods , Antibodies, Monoclonal/chemistry , Antigens/chemistry , Biotinylation , Epitopes/chemistry , Fluorescent Dyes/chemistry , Humans , Immunoglobulin G/chemistry , Immunoglobulin M/chemistry , Immunophenotyping/methods , Phenotype , Reproducibility of Results
17.
Curr Protoc Cytom ; Chapter 6: Unit 6.2, 2001 May.
Article in English | MEDLINE | ID: mdl-18770715

ABSTRACT

This unit presents basic techniques for immunophenotyping by flow cytometry, direct using a conjugated monoclonal antibody and indirect using an unconjugated primary antibody followed by a conjugated secondary antibody. Combinations of these methods are described for two-, three-, and four-color staining. Analysis of data acquired from cells stained by these procedures is detailed. A procedure is given for the detection of the location of nonviable cells so that they can be gated out of the analysis.


Subject(s)
Antibodies, Monoclonal/analysis , Flow Cytometry/methods , Immunophenotyping/methods , Animals , Antibodies/chemistry , Cell Separation/methods , Fluorescent Dyes/pharmacology , Humans
18.
Cytometry ; 38(4): 161-75, 1999 Aug 15.
Article in English | MEDLINE | ID: mdl-10440854

ABSTRACT

Four-color immunophenotyping can now be routinely performed using either a single laser or dual laser flow cytometer. When a single laser instrument is used, the fluorochromes evaluated are usually FITC, PE, PE-TR and PE-CY5 (or PerCP). For two-laser excitation APC is generally used in place of PE-TR. Since each tandem dye construct contains PE, three of the four detectors are affected and compensation can be problematic. In this report we show that each tandem conjugated antibody, whether different batches from the same supplier or conjugates from different suppliers all require unique compensation. This inconsistency results in erroneous data, negates the use of single labeled particles as a method for providing adequate compensation and requires dual and triple labeled cells of known pattern to verify compensation. It is also shown that improper compensation can reduce or eliminate completely the detection of fluorescence emission from PECY5 conjugated antibodies. These problems are caused by a variation in energy transfer between PE and either TR or CY5 because the chemistry involved in preparation and conjugation to antibodies is not sufficiently controlled to produce reagents with uniform compensation requirements. The variation in tandem dye compensation can be addressed by either using the same tandem conjugated antibody, by using the same second step tandem reagent to an appropriate first step antibody or by using software compensation. The latter provides an easy solution because a unique compensation matrix can be produced for each antibody tandem conjugate.


Subject(s)
Flow Cytometry/standards , Immunophenotyping/methods , Antibodies/metabolism , Calibration , Coloring Agents/metabolism , Fluorescein-5-isothiocyanate/metabolism , Humans , Lasers
19.
J Immunol ; 157(11): 4771-80, 1996 Dec 01.
Article in English | MEDLINE | ID: mdl-8943378

ABSTRACT

Engagement of CD28 induces a major costimulatory pathway required by many CD4+ T cells in addition to activation via the TCR. In the absence of signals provided by CD28, ligation of the TCR alone can induce anergy or apoptosis in CD28+ cells. However, we report here characterization of a distinct subset of CD4+ T cells that are CD28-. Three autoreactive CD4+ human T cell clones that could be activated to produce IL-2 and proliferate by anti-CD3 alone were found to lack expression of CD28. CD28- clones that were activated with anti-CD3 alone were not anergic to restimulation via CD3. The presence of CD28-CD4+ T cells was verified in peripheral blood, and their frequency ranged from 0% to >22% of CD4+ T cells in different individuals. The percentage of CD28-CD4+ T cells in the peripheral blood of 57 individuals was significantly correlated with specific class II MHC alleles. Persons with HLA-DRB1*0401 and DR1 alleles had significantly higher numbers of CD28- T cells, while individuals with HLA-DR2(15) had significantly fewer CD28-CD4+ T cells than the mean. Like the CD28- clones, CD28-CD4+ T cells isolated from peripheral blood proliferated upon CD3 cross-linking in the absence of costimulation. The finding that CD28-CD4+ T cells resist induction of anergy following engagement of the TCR in the absence of conventional costimulation demonstrates one mechanism by which autoreactive T cells can escape processes that censor self-reactivity. The MHC associations observed suggest a relationship with autoimmunity and loss of self-tolerance.


Subject(s)
CD28 Antigens/metabolism , CD4-Positive T-Lymphocytes/classification , CD4-Positive T-Lymphocytes/immunology , HLA-DR Antigens/genetics , Macrophage-1 Antigen/metabolism , Alleles , Antibodies , CD3 Complex , CD4 Antigens/metabolism , Clone Cells , Humans , In Vitro Techniques , Interleukin-2/biosynthesis , Lymphocyte Activation
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