Fibronectin on activated T lymphocytes is bound to gangliosides and is present in detergent insoluble microdomains

Increased blood levels of cellular fibronectin in asthma: Relation to the asthma severity, inflammation, and prothrombotic blood alterations

BACKGROUND

Recently, we have reported that asthma is characterized by prothrombotic blood alterations, which were related to the low-grade inflammatory state. Inflammation, however, may also lead to vascular dysfunction. The aim of this study was to evaluate plasma levels of cellular fibronectin (cFN), a marker of vascular injury in asthmatics, and to analyze their impact on described previously prothrombotic blood alterations.

METHODS

In a cross-sectional study, we investigated 164 adult stable asthmatics and 72 matched controls. Plasma cFN was measured using an ELISA. Its relations to inflammation, thrombin generation, fibrinolytic capacity, expressed as clot lysis time (CLT), and platelet markers were evaluated.

RESULTS

Asthma was associated with 50.1% higher plasma cFN levels as compared with controls (p < 0.001, after adjustment for potential confounders). There was a positive association of cFN with asthma severity and inverse with the FEV₁/VC index (β = 0.2 [95%CI:0.13-0.28] and β = -0.15 [95%CI: -0.23 to -0.07], respectively). In asthmatics cFN positively correlated with high-sensitivity C-reactive protein (β = 0.24 [95%CI:0.16-0.32]), fibrinogen (β = 0.13 [95%CI:0.04-0.21]), interleukin-6 (β = 0.23 [95%CI:0.15-0.3]), platelet factor 4 (β = 0.14 [95%CI:0.06-0.21]), plasminogen (β = 0.11 [95%CI:0.04-0.19]) and CLT (β = 0.35 [95%CI:0.28-0.42]). In both groups cFN was related to the endogenous thrombin potential (ETP) (β = 0.51 [95%CI:0.44-0.57], and β = 0.17 [95%CI:0.07-0.27], respectively). Multiple regression models showed that cFN was the most potent independent predictor of both ETP and CLT in asthmatics.

CONCLUSION

Presented study is the first to show increased plasma cellular fibronectin in asthma, which is associated with disease severity, inflammation, and prothrombotic blood alterations. This novel observation suggests a previously unknown modulator of prothrombotic plasma properties in asthmatics.

Integrins in T Cell Physiology

From the thymus to the peripheral lymph nodes, integrin-mediated interactions with neighbor cells and the extracellular matrix tune T cell behavior by organizing cytoskeletal remodeling and modulating receptor signaling. LFA-1 (αLβ2 integrin) and VLA-4 (α4β1 integrin) play a key role throughout the T cell lifecycle from thymocyte differentiation to lymphocyte extravasation and finally play a fundamental role in organizing immune synapse, providing an essential costimulatory signal for the T cell receptor. Apart from tuning T cell signaling, integrins also contribute to homing to specific target organs as exemplified by the importance of α4β7 in maintaining the gut immune system. However, apart from those well-characterized examples, the physiological significance of the other integrin dimers expressed by T cells is far less understood. Thus, integrin-mediated cell-to-cell and cell-to-matrix interactions during the T cell lifespan still represent an open field of research.

Activation and propagation of tumor-infiltrating lymphocytes on clinical-grade designer artificial antigen-presenting cells for adoptive immunotherapy of melanoma

PURPOSE

Adoptive cell therapy with autologous tumor-infiltrating lymphocytes (TIL) is a therapy for metastatic melanoma with response rates of up to 50%. However, the generation of the TIL transfer product is challenging, requiring pooled allogeneic normal donor peripheral blood mononuclear cells (PBMC) used in vitro as "feeders" to support a rapid-expansion protocol. Here, we optimized a platform to propagate TIL to a clinical scale using K562 cells genetically modified to express costimulatory molecules such as CD86, CD137-ligand, and membrane-bound IL-15 to function as artificial antigen-presenting cells (aAPC) as an alternative to using PBMC feeders.

EXPERIMENTAL DESIGN

We used aAPC or γ-irradiated PBMC feeders to propagate TIL and measured rates of expansion. The activation and differentiation state was evaluated by flow cytometry and differential gene expression analyses. Clonal diversity was assessed on the basis of the pattern of T-cell receptor usage. T-cell effector function was measured by evaluation of cytotoxic granule content and killing of target cells.

RESULTS

The aAPC propagated TIL at numbers equivalent to that found with PBMC feeders, whereas increasing the frequency of CD8 T-cell expansion with a comparable effector-memory phenotype. mRNA profiling revealed an upregulation of genes in the Wnt and stem-cell pathways with the aAPC. The aAPC platform did not skew clonal diversity, and CD8 T cells showed comparable antitumor function as those expanded with PBMC feeders.

CONCLUSIONS

TIL can be rapidly expanded with aAPC to clinical scale generating T cells with similar phenotypic and effector profiles as with PBMC feeders. These data support the clinical application of aAPC to manufacture TIL for the treatment of melanoma.

Fibronectin in the palatine tonsil as a susceptibility marker in Egyptian rheumatic families: histological and immunohistochemical studies

Rheumatic fever (RF) and rheumatic heart disease (RHD) are the multisystem autoimmune sequel of group A streptococci (GAS) infection of the upper respiratory passages, mainly tonsillopharyngitis. The major receptor on the surface of human palatine tonsil for GAS is fibronectin (FN; adhesin receptor). Early detection of RF susceptibility is considered as an important aim of this study. Therefore, the present study aimed to use FN immunoreactivity (FN-ir) as a marker for early detection of rheumatic susceptible children with palatine tonsil crypts surface epithelium. A total of 30 palatine tonsillar specimens were obtained from children aged from 3 to 15 years. Histological studies showed moderate vascular changes and more than four apparent epithelial disruptions in the crypt epithelium. FN-ir showed a significant increase in FN in the basal layers of surface epithelium, subepithelial connective tissue and interfollicular areas. Tonsils of children in rheumatic families showed significant increase in FN in subepithelial connective tissue areas with more than one apparent crypt epithelial disruption compared to normal children. We can conclude that FN plays a central role in the RF and differentially distributed in the functional compartments of the palatine tonsil in children with RHD, so FN-ir can be used as a marker for rheumatic susceptibility.

Protein kinase C and NF-κB-dependent CD4 downregulation in macrophages induced by T cell-derived soluble factors: consequences for HIV-1 infection

Upon activation, CD4(+) T cells release cytokines, chemokines, and other soluble factors that influence the kinetics of HIV-1 replication in macrophages (M). In this article, we show that activation of human primary T cells suppresses the early stages of HIV-1 replication in human primary Mφ by downregulating the main cellular receptor for the virus CD4. The secreted factors responsible for this effect have a molecular mass greater than conventional cytokines, are independent of Th1 or Th2 polarization, and are not IFN-γ, IL-16, RANTES, or macrophage inhibitory factor, as revealed by cytokine array analysis and neutralization assays. CD4 downregulation is entirely posttranslational and involves serine phosphorylation of CD4 and its targeting to an intracellular compartment destined for acidification and degradation. CD4 downregulation is dependent on the activities of both protein kinase C and NF-κB as well as the proteasomes. Using high-resolution liquid chromatography-tandem mass spectrometry analysis in conjugation with label-free protein quantitation software, we found that proteins that promote Mφ adherence and spreading, such as attractin, fibronectin, and galectin-3-binding protein, were significantly overrepresented in the activated T cell supernatant fractions. These results reveal the existence of previously unreported anti-HIV-1 proteins, released by activated T cells that downregulate CD4 expression, and are of fundamental importance to understand the kinetics of HIV infection in vivo.

Expression of the oncofetal ED-B–containing fibronectin isoform in hematologic tumors enables ED-B–targeted 131I-L19SIP radioimmunotherapy in Hodgkin lymphoma patients

Current treatment of hematologic malignancies involves rather unspecific chemotherapy, frequently resulting in severe adverse events. Thus, modern clinical research focuses on compounds able to discriminate malignant from normal tissues. Being expressed in newly formed blood vessels of solid cancers but not in normal mature tissues, the extradomain B of fibronectin (ED-B FN) is a promising target for selective cancer therapies. Using immunohistology with a new epitope retrieval technique for paraffin-embedded tissues, ED-B FN expression was found in biopsies from more than 200 Hodgkin and non-Hodgkin lymphoma patients of nearly all entities, and in patients with myeloproliferative diseases. ED-B FN expression was nearly absent in normal lymph nodes (n = 10) and bone marrow biopsies (n = 9). The extent of vascular ED-B FN expression in lymphoma tissues was positively correlated with grade of malignancy. ED-B FN expression was enhanced in lymph nodes with severe lymphadenopathy and in some hyperplastic tonsils. The in vivo accessibility of ED-B FN was confirmed in 3 lymphoma patients, in whom the lymphoma lesions were visualized on scintigraphy with 131I-labeled L19 small immunoprotein (131I-L19SIP). In 2 relapsed Hodgkin lymphoma patients131I-L19SIP radioimmunotherapy induced a sustained partial response, qualifying ED-B FN as a promising target for antibody-based lymphoma therapies.

Crosslinking of CD66B on peripheral blood neutrophils mediates the release of interleukin-8 from intracellular storage

Crosslinking of CD66 antigens on the neutrophil surface induces functional responses such as aggregation of the cells and protein kinase activity. Although CD66b (carcinoembryonic antigen-related cell adhesion molecule-8) has been reported as a candidate receptor for galectin-3, its natural ligand is still unknown and therefore its physiologic function remains to be elucidated. We were able to detect the storage of intracellular interleukin-8 (IL-8) in unstimulated human neutrophils and its secretion in response to the crosslinking of CD66b. In contrast to lipopolysaccharide (LPS), the stimulation via CD66b does not induce a de novo synthesis of cytokines but rather a directed release of the preformed IL-8. This process may represent a very low state of activation for the neutrophil. As it extravasates into the tissue, the neutrophil might interact with the extracellular matrix via CD66b. In response to this interaction, polymorphonuclear neutrophils (PMN) release their preformed IL-8, establishing a chemotactic track for other cells to follow. By contact with pathogenic stimuli such as LPS in the infected tissue, the neutrophil then becomes fully activated and is able to synthesize cytokines de novo to release greater quantities.