RESUMEN
Cognitive impairment is highly prevalent among individuals with late-life depression (LLD) and tends to persist even after successful treatment. The biological mechanisms underlying cognitive impairment in LLD are complex and likely involve abnormalities in multiple pathways, or 'cascades,' reflected in specific biomarkers. Our aim was to evaluate peripheral (blood-based) evidence for biological pathways associated with cognitive impairment in older adults with LLD. To this end, we used a data-driven comprehensive proteomic analysis (multiplex immunoassay including 242 proteins), along with measures of structural brain abnormalities (gray matter atrophy and white matter hyperintensity volume via magnetic resonance imaging), and brain amyloid-ß (Aß) deposition (PiB-positron emission tomography). We analyzed data from 80 older adults with remitted major depression (36 with mild cognitive impairment (LLD+MCI) and 44 with normal cognitive (LLD+NC)) function. LLD+MCI was associated with differential expression of 24 proteins (P<0.05 and q-value <0.30) related mainly to the regulation of immune-inflammatory activity, intracellular signaling, cell survival and protein and lipid homeostasis. Individuals with LLD+MCI also showed greater white matter hyperintensity burden compared with LLD+NC (P=0.015). We observed no differences in gray matter volume or brain Aß deposition between groups. Machine learning analysis showed that a group of three proteins (Apo AI, IL-12 and stem cell factor) yielded accuracy of 81.3%, sensitivity of 75% and specificity of 86.4% in discriminating participants with MCI from those with NC function (with an averaged cross-validation accuracy of 76.3%, sensitivity of 69.4% and specificity of 81.8% with nested cross-validation considering the model selection bias). Cognitive impairment in LLD seems to be related to greater cerebrovascular disease along with abnormalities in immune-inflammatory control, cell survival, intracellular signaling, protein and lipid homeostasis, and clotting processes. These results suggest that individuals with LLD and cognitive impairment may be more vulnerable to accelerated brain aging and shed light on possible mediators of their elevated risk for progression to dementia.
Asunto(s)
Biomarcadores/sangre , Encéfalo/patología , Trastornos del Conocimiento/etiología , Depresión , Proteínas/metabolismo , Anciano , Anciano de 80 o más Años , Compuestos de Anilina , Benzotiazoles/farmacocinética , Encéfalo/diagnóstico por imagen , Depresión/sangre , Depresión/complicaciones , Depresión/patología , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Aprendizaje Automático , Imagen por Resonancia Magnética , Masculino , Pruebas Neuropsicológicas , Tomografía de Emisión de Positrones , Proteómica/métodos , Escalas de Valoración Psiquiátrica , TiazolesRESUMEN
Considerable evidence has accumulated indicating that cultured human or rodent tumor cells can be successfully transduced with cytokine genes and selected in the appropriate antibiotic-containing culture media. The selected transductants are generally able to secrete the cytokine coded for by the transduced gene, and in many cases, substantial levels (e.g., ng quantities) of the cytokine are produced. Using retroviral vectors, it has been possible to obtain stably transduced tumor cells with a variety of cytokine genes (1-4). These tumor cells have been used for immunotherapy of cancer in numerous animal models of tumor growth or metastasis, and more recently, in vaccination protocols in patients with cancer. One possible criticism that can be leveled at this type of vaccination approach is that cultured, genetically modified, and selected tumor cells might have phenotypic characteristics that are substantially different from those of unmodified tumor cells. Since retroviral vectors are often used for transduction, it is also possible that viral antigens expressed on transduced tumor cells contribute to the immune response generated as a result of vaccination. Also, primary cultures of human tumor cells are often difficult to establish and maintain.
RESUMEN
The B16/BL6 melanoma is a relatively nonimmunogenic tumor expressing low levels of MHC class I molecules. BL6 clones expressing transfected H-2Kb class I molecules were, by contrast, highly immunogenic in immunocompetent mice. Tumor-infiltrating lymphocytes (TILs) generated from the H-2Kb+ BL6 lesions (Thy 1.2+, CD8+, CD4-) efficiently lysed H-2Kb+ melanoma (CL8-1 and 2Kb38) and the H-2Kb+ nonrelated 3-methylcholanthrene (MCA)-105 sarcoma, but not the H-2Kb- parental melanoma BL6-8. This strongly suggests that CL8-1, 2Kb38, and MCA-105 express identical or cross-reactive T cell epitopes recognized by CL8-1 TILs in the context of the H-2Kb class I allele. To identify the T cell epitopes, peptides were acid-eluted from various cells, and fractionated by HPLC. Five HPLC fractions (F1mel-F5mel) of 70 tested contained peptides derived from H-2Kb+ CL8-1 melanoma (but not H-2Kb- melanomas) that were capable of conferring susceptibility to CL8-1 TIL lysis on H-2b-expressing target cells (EL4, C1R.Kb), but not on H-2d-expressing P815 target cells. CL8-1 TILs failed to recognize peptides derived from H-2Kb+ nonmelanoma targets such as EL4 or normal B6 splenocytes. Interestingly, CL8-1 TILs appeared to recognize peptide species contained in two HPLC fractions derived from the MCA-105 sarcoma (F1sar and F5sar). Conversely, TILs derived from MCA-105 lesions recognized MCA-105 and CL8-1 tumor cells, as well as F5mel and F5sar peptides presented by EL4 targets. These data support common murine tumor-associated peptide epitopes presented by H-2Kb and recognized by CD8+ CTLs derived from histologically distinct tumors, melanoma and sarcoma.
Asunto(s)
Células Presentadoras de Antígenos/inmunología , Antígenos de Neoplasias/inmunología , Antígenos H-2/inmunología , Linfocitos Infiltrantes de Tumor/inmunología , Melanoma Experimental/inmunología , Sarcoma Experimental/inmunología , Animales , Antígenos de Neoplasias/química , Antígenos CD8/análisis , Citotoxicidad Inmunológica , Epítopos , Femenino , Ratones , Ratones Endogámicos C57BL , Péptidos/inmunología , Subgrupos de Linfocitos T/inmunologíaRESUMEN
Interleukin-2 (IL-2) is a soluble factor produced by T cells that stimulates growth and activity of lymphocytes and other immune cells. First noted in murine studies, the antitumor efficacy of IL-2 has been shown to induce partial and complete regression of some tumors in human clinical trials over the past decade. Although the initial clinical success of IL-2 was in combination with lymphokine-activated killer cells, IL-2 alone has subsequently been shown to be equally efficacious. Combinations of cytokines and chemotherapies with IL-2 have been generally inconclusive and disappointing with the possible exception of interferon-alpha. Toxicities of IL-2 are common and often dose limiting. Symptomatic therapy has allowed patients to tolerate somewhat higher doses, but has not addressed the underlying mechanisms of these toxicities which may involve mediators such as tumor necrosis factor, interferon-gamma, and nitric oxide. Clinical studies assessing these factors for their involvement in the antitumor effects of IL-2 as well as its toxicities may allow better understanding of IL-2, and perhaps lead to improved cancer therapies.
Asunto(s)
Interleucina-2/uso terapéutico , Neoplasias/terapia , Animales , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Terapia Combinada , Citocinas/uso terapéutico , Humanos , Inmunoterapia Adoptiva , Interleucina-2/efectos adversosRESUMEN
Tumor-infiltrating lymphocytes (TIL) freshly obtained from human malignant melanomas as well as the same TIL grown in the presence of interleukin 2 (IL2) were studied for gene expression of the T-cell receptor (TCR) variable beta regions (V beta). To perform the TCR-V beta analysis, total RNA was isolated from TIL and reverse-transcribed into cDNA, which was then amplified by PCR using 22 different 5' primers specifically recognizing the sequences of 20 V beta gene families and a 3' primer annealing to the constant region of the beta chain. The TCR-alpha constant region (C alpha) gene was co-amplified as a standard for the calculation of the percentage of each TCR-V beta gene expressed. The frequency of individual V beta regions expressed on TIL was computed from the ratio of cpm V beta to cpm C alpha for each V beta region in relation to the total of all 22 ratios. With fresh TIL obtained from 8 different melanomas, oligoclonal distribution of V beta genes expressed on TIL was observed, in comparison with a broader and unrestricted distribution seen with peripheral-blood T cells of 8 normal individuals. The oligoclonal patterns of V beta-gene expression in fresh melanoma TIL were distinct in every tumor. Several of the V beta-genes usually expressed in normal PBL were not expressed in fresh TIL in melanoma TIL cultured in the presence of IL2 and IL4 and in the absence of autologous tumor (AuTu) or antigen-presenting cells for 23 to 65 days, selection of T-cell lines expressing a restricted number of V beta genes occurred. Although in 4/5 TIL cultures this selection involved the V beta 7 gene, no relationship could be established between V beta gene expression in fresh TIL and that in T-cell lines outgrowing in long-term cultures. Selection in culture of CD3+CD8+ T-cell lines with V beta-gene expression restricted to 1 or 2 V beta families did not correlate with the presence or level of AuTu cytotoxicity mediated by these T cells. The results indicate that in TIL cultures random selection of T-cell lines with reactivity not relevant to AuTu may account for poor expression or loss of AuTu cytotoxicity by most TIL cultured long-term in the presence of cytokines and in the absence of specific antigenic stimulation.