Rapid Isolation of Rare Isotype-Switched Hybridoma Variants: Application to the Generation of IgG2a and IgG2b MAb to CD63, a Late Endosome and Exosome Marker.

CD63, a member of the tetraspanin superfamily, is used as a marker of late endosomes and lysosome-related organelles, as well as a marker of exosomes. Here, we selected rare isotype variants of TS63 by sorting hybridoma cells on the basis of their high expression of surface immunoglobulins of the IgG2a and IgG2b subclass. Pure populations of cells secreting IgG2a and IgG2b variants of TS63 (referred to as TS63a and TS63b) were obtained using two rounds of cell sorting and one limited dilution cloning step.

New insights into the tetraspanin Tspan5 using novel monoclonal antibodies.

Tspan5 is a member of a subgroup of tetraspanins referred to as TspanC8. These tetraspanins directly interact with the metalloprotease ADAM10, regulate its exit from the endoplasmic reticulum and subsequent trafficking, and differentially regulate its ability to cleave various substrates and activate Notch signaling. The study of Tspan5 has been limited by the lack of good antibodies.

Multi-factorial modulation of colorectal carcinoma cells motility - partial coordination by the tetraspanin Co-029/tspan8.

Colorectal carcinoma cells Isreco1 display an ability to migrate controlled by a complex set of signals issued from the membrane. By comparing cells infected by mycoplasmas and mycoplasmas free cells, we have established that basal 2D migration is dependent on a double signal mediated by the collagen receptors integrins alpha1/2 and the Toll-Like receptor TLR2. The signal issued from mycoplasmas can be replaced by a TLR2 ligand and the functional effect is neutralized by silencing of MyD88.

Effect of an anti-human Co-029/tspan8 mouse monoclonal antibody on tumor growth in a nude mouse model.

New therapeutic agents are needed in digestive tract tumors. Co-029/tspan8 is a tetraspanin frequently expressed on human colorectal tumors, In this work, we report the effects of the monoclonal antibody Ts29.2, targeting Co-029/tspan8, on colorectal tumor cells in vitro and after implantation in nude mice.

Metabolic syndrome in French HIV-infected patients: prevalence and predictive factors after 3 years of antiretroviral therapy.

Treatment of HIV infection with highly active antiretroviral therapy can induce metabolic complications and increase the risk of developing the metabolic syndrome (MS). The purpose of this study was to report the prevalence and the risk factors for MS in HIV-infected patients who started highly active antiretroviral therapy (HAART) after 2000. SYMET is a prospective, multicentric, cohort study evaluating the prevalence of MS in 269 patients who had received continuous HAART for 1 to 4 years up to September 2007.

A multicenter prospective observational study of the conformity of temozolomide prescriptions in France.

Context: Temozolomide (TMZ) is approved for the treatment of high-grade gliomas such as glioblastoma (GBM) multiforme and refractory anaplastic astrocytoma, but it is also used in indications not mentioned in the summary of product characteristics (SPC). The main objective of this study was to evaluate the conformity of TMZ prescriptions to the French SPC and prescription guidebook.

Methods: We conducted a prospective observational study of all consecutive patients treated with TMZ in 21 French hospitals between September 2006 and February 2007, accounting for 39% of total TMZ consumption in France.

Tetraspanins regulate ADAM10-mediated cleavage of TNF-alpha and epidermal growth factor.

Several cytokines and growth factors are released by proteolytic cleavage of a membrane-anchored precursor, through the action of ADAM (a disintegrin and metalloprotease) metalloproteases. The activity of these proteases is regulated through largely unknown mechanisms. In this study we show that Ab engagement of several tetraspanins (CD9, CD81, CD82) increases epidermal growth factor and/or TNF-alpha secretion through a mechanism dependent on ADAM10.

Cholesterol contributes to the organization of tetraspanin-enriched microdomains and to CD81-dependent infection by malaria sporozoites.

Tetraspanins constitute a family of widely expressed integral membrane proteins that associate extensively with one another and with other membrane proteins to form specific membrane microdomains distinct from conventional lipid rafts. So far, because of the lack of appropriate tools, the functionality of these microdomains has remained largely unknown. Here, using a new monoclonal antibody that only binds to the tetraspanin CD81 associated with other tetraspanins, we show that membrane cholesterol contributes to the organization of tetraspanin microdomains on the surface of live cells.

Profiling of the tetraspanin web of human colon cancer cells.

Tetraspanins are integral membrane proteins involved in a variety of physiological and pathological processes. In cancer, clinical and experimental studies have reported a link between tetraspanin expression levels and metastasis. Tetraspanins play a role as organizers of multimolecular complexes in the plasma membrane.

A physical and functional link between cholesterol and tetraspanins.

By interacting with each others, the tetraspanins are thought to assemble a network of molecular interactions, the tetraspanin web. These tetraspanin/tetraspanin interactions involve in part the palmitoylation of the proteins. We show that tetraspanins interact with cholesterol as indicated by the precipitation of tetraspanin/tetraspanin complexes by digitonin, a cholesterol-precipitating reagent, and the labeling of the tetraspanins CD9, CD81 and CD82 with a photoactivatable cholesterol in vivo.

[Clinical trials and outpatient dispensation: the pharmaceutical counseling place].

Drug dispensations in clinical trials essentially concern outpatients (90%), and several mistakes and bad uses have been noted. The aim of this work is to set up a pharmaceutical counselling for outpatients in clinical trials. The bibliographic research on this subject did not learn us about similar experiences, but several references helped us to select the support of information: personal meeting between patient and pharmacist to introduce a written leaflet.

EWI-2 is a new component of the tetraspanin web in hepatocytes and lymphoid cells.

Several tetraspanins bind directly to a few molecular partners to form primary complexes, which might assemble through tetraspanin-tetraspanin interactions to form a network of molecular interactions, the tetraspanin web. We have produced a monoclonal antibody directed to a 63 kDa molecule (determined under non-reducing conditions) associated with CD9. This molecule was first identified by MS as a molecule with four Ig domains, EWI-2.

Multiple levels of interactions within the tetraspanin web.

The tetraspanin web refers to a network of molecular interactions involving tetraspanins and other molecules. Inside the tetraspanin web, small primary complexes containing only one tetraspanin and one specific partner molecule such as CD151/alpha3beta1 integrin and CD9/CD9P-1 (FPRP) can be observed under particular conditions. Here we demonstrate that when cells are lysed with Brij97, the tetraspanins CD151 and CD9 allow and/or stabilize the interaction of their partner molecules with other tetraspanins and that their two partners associate under conditions maintaining tetraspanin/tetraspanin interactions.

Differential stability of tetraspanin/tetraspanin interactions: role of palmitoylation.

The tetraspanins associate with various surface molecules and with each other to build a network of molecular interactions, the tetraspanin web. The interaction of tetraspanins with each other seems to be central for the assembly of the tetraspanin web. All tetraspanins studied, CD9, CD37, CD53, CD63, CD81, CD82 and CD151, were found to incorporate [3H]palmitate.