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Objective. To analyze the fine specificity of IgG autoantibodies in sera from rheumatoid arthritis (RA) patients for type II collagen (CII) epitopes that are arthritogenic in collagen-induced arthritis (CIA), a relevant murine model of RA.Methods. For enzyme-linked immunosorbent assay (ELISA) analysis of conformation-dependent autoantibody binding, recombinant chimeric collagens that harbor the respective CII epitopes as an insertion within the frame of a constant type X collagen triple helix were constructed. In addition, synthetic peptides mimicking the native collagen structures were applied for the first time in the ELISA assessment of humoral CII autoimmunity.Results. The pathogenicity of IgG responses to certain CII determinants in CIA was demonstrated by arthritis development in BALB/c mice upon the combined transfer of 2 mouse monoclonal antibodies specific for precisely mapped conformational CII epitopes (amino acid residues 359-369 [C1 III ] and 551-564[J1]), whereas antibodies to another epitope (F4) were not arthritogenic. To test whether human autoimmune responses are similarly directed to these conserved CII determinants, serum IgG was analyzed. The prevalence of sera with increased IgG binding to the C1 III epitope was significantly higher in RA compared with sera from healthy donors or from patients with other rheumatic conditions, e.g., osteoarthritis (OA), systemic lupus erythematosus (SLE), or relapsing polychondritis (RP), whereas levels of antibodies specific for the nonarthritogenic F4 epitope were associated with OA rather than RA.Conclusion. Autoimmunity to CII, although detectable in different rheumatic conditions, differs in fine specificity between distinct disease entities. In RA, in contrast to degenerative joint disease, RP, and SLE, autoantibody responses are directed to an evolutionary conserved CII structure that is also targeted by pathogenic autoimmune responses in murine models of arthritis.

Annexins constitute an evolutionary conserved multigene protein superfamily characterized by their ability to interact with biological membranes in a calcium dependent manner. They are expressed by all living organisms with the exception of certain unicellular organisms. The vertebrate annexin core is composed of four (eight in annexin A6) homologous domains of around 70 amino acids, with the overall shape of a slightly bent ring surrounding a central hydrophilic pore. Calcium- and phospholipid-binding sites are located on the convex side while the N-terminus links domains I and IV on the concave side. The N-terminus region shows great variability in length and amino acid sequence and it greatly influences protein stability and specific functions of annexins. These proteins interact mainly with acidic phospholipids, such as phosphatidylserine, but differences are found regarding their affinity for lipids and calcium requirements for the interaction. Annexins are involved in a wide range of intra- and extracellular biological processes in vitro, most of them directly related with the conserved ability to bind to phospholipid bilayers: membrane trafficking, membrane-cytoskeleton anchorage, ion channel activity and regulation, as well as antiinflammatory and anticoagulant activities. However, the in vivo physiological functions of annexins are just beginning to be established.

Strategies to enhance the immunogenicity of tumors are urgently needed. Although vaccination with irradiated dying lymphoma cells recruits a tumor-specific immune response, its efficiency as immunogen is poor. Annexin V (AxV) binds with high affinity to phosphatidylserine on the surface of apoptotic and necrotic cells and thereby impairs their uptake by macrophages. Here, we report that AxV preferentially targets irradiated lymphoma cells to CD8+ dendritic cells for in vivo clearance, elicits the release of proinflammatory cytokines and dramatically enhances the protection elicited against the tumor. The response was endowed with both memory, because protected animals rejected living lymphoma cells after 72 d, and specificity, because vaccinated animals failed to reject unrelated neoplasms. Finally, AxV–coupled irradiated cells induced the regression of growing tumors. These data indicate that endogenous adjuvants that bind to dying tumor cells can be exploited to target tumors for immune rejection.

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4F2hc (CD98hc, FRP-1, and SLC3A2) is a multifunctional type II membrane glycoprotein involved in amino acid transport (1), cell fusion (2), and ␤1 integrin-dependent adhesion (3). 4F2hc and the homologous rBAT are the heavy subunits of the heteromeric amino acid transporters (HATs), 4 which are linked by a disulfide bridge to the catalytic light subunit (Fig. 1A). One of six light subunits (LAT1, LAT2, y ϩ LAT1, y ϩ LAT2, asc-1, and xCT) heterodimerizes with 4F2hc, thereby rendering a range of transport activities. 4F2hc-associated light subunits are involved in human pathology (yϩLAT1 mutations cause lysinuric protein intolerance, and xCT is the receptor of Kaposi sarcoma-associated herpesvirus (4 -6)). The known role of the heavy subunits is to bring the holotransporter to the plasma membrane. Moreover, 4F2hc is involved in cellular transformation because it is highly expressed in tumor cells; its expression correlates with tumor development, progression, and metastatic potential; and its overexpression leads to cell transformation (7-10). 4F2hc is a mediator of ␤1 integrin signaling (11). Recently, a metabolic activation-related CD147-4F2 complex has been identified on the cell surface that may play a critical role in energy metabolism, probably by coordinating the transport of lactate (via MCT1 and MCT4) and amino acids (via LAT1) (12). Integrin interaction and the CD147-4F2 complex may explain the role of 4F2hc in cellular transformation.The role of the big ectodomain of the heavy subunits of HATs remains largely unknown. The 4F2hc ectodomain (4F2hc-ED) is required for plasma membrane localization of the light subunits LAT2 and y ϩ LAT2 (13). 4F2hc-ED might also modulate ␤1 integrin function and tumorigenicity (10), although interactions with ␤1 integrins involve the transmembrane and the *

The aim of this study was to examine the fascia transversalis (FT) from patients with direct and indirect hernia in an attempt to identify possible differences between each type of hernia. FT samples were obtained from 36 patients presenting inguinal hernia (23 indirect hernia and 13 direct hernia) who underwent surgery. We have analysed the ultrastructure of the fascia surrounding the hernial lesions, the proline and lysine hydroxylation in the tissue, the type I-type III collagen ratio and the presence of metalloproteinases. We have not detected ultrastructural differences in the collagen fibrils from FT in direct and indirect hernias. However, the interfibrillar matrix was more abundant in direct hernias, showing abundant electron-dense particles. No differences in proline hydroxylation were observed between each type of hernia. A small decrease in lysine hydroxylation was detected in patients with direct hernia. Enzyme-linked immunosorbent assays (ELISAs) showed no statistically significant differences in the type I-type III collagen absorbance ratios. Immunohistochemistry revealed no differences in the expression of matrix metalloproteinase-1. FT from patients presenting direct hernia showed a very strong staining vs. metalloproteinase-2 when compared with that observed in indirect hernia.

The implication of the tetraspanin CD9 in cancer has received much recent attention and an inverse correlation between CD9 expression and the metastatic potential and cancer survival rate has been established for different tumor types. In contrast to the well-established role of CD9 in metastasis, very little is known about the involvement of this tetraspanin in the process of development of primary tumors. In the present study, we present evidence on the implication of CD9 in colon carcinoma tumorigenesis. We report here that ectopic expression of CD9 in colon carcinoma cells results in enhanced integrin-dependent adhesion and inhibition of cell growth. Consistently with these effects, treatment of these cells with anti-CD9-specific antibodies resulted in (i) increased b1 integrin-mediated cell adhesion through a mechanism involving clustering of integrin molecules rather than altered affinity; (ii) induction of morphological changes characterized by the acquisition of an elongated cell phenotype; (iii) inhibition of cell proliferation with no significant effect on cell survival; (iv) increased expression of membrane TNF-a, and finally (v) inhibition of the in vivo tumorigenic capacity in nude mice. In addition, through the use of selective blockers of TNF-a, we have demonstrated that this cytokine partly mediates the antiproliferative effects of CD9. These results clearly establish for the first time a role for CD9 in the tumorigenic process. ' 2007 Wiley-Liss, Inc.Key words: CD9; TNF-a; proliferation; tumorigenicity; tetraspanin The tetraspanin CD9 is a widely distributed surface molecule implicated in diverse functions, including cell signaling, growth, adhesion and motility, metastasis and sperm-egg fusion. Like other members of the tetraspanin protein family, CD9 participates in the organization of cell surface protein microdomains, termed ''the tetraspanin web,'' through association with other transmembrane proteins including members of the integrin family of adhesion receptors. [1][2][3] The implication of CD9 in cancer has received much attention. An inverse correlation between its expression in primary tumors and the metastatic potential and patient survival rate has been established for melanomas and colon, lung and breast carcinomas. 1,4-8 The involvement of this tetraspanin in tumor progression has been inferred from the effects of CD9 antibodies or CD9 overexpression on tumor cell motility and migration. In this regard, it has been shown that overexpression of this tetraspanin in melanoma and breast, lung, pancreas and colon carcinoma cells suppresses the motility and metastatic potential of these cells. 5,7,9,10 mAbs directed to the CD9 molecule have also been shown to inhibit the migration of different types of carcinoma tumor cells and the transendothelial migration of melanoma cells. 11-13 Therefore, the inverse correlation observed between CD9 expression and the metastatic potential could be explained, at least in part, by the effects mediated by CD9 on cell adhesion and migration through the ...