Basigin (Bsg) is a highly glycosylated transmembrane protein with two immunoglobulin (Ig)-like domains. A number of studies, including gene targeting, have demonstrated that Bsg plays pivotal roles in spermatogenesis, implantation, neural network formation and tumor progression. In the present study, to understand the mechanism of action of Bsg, we determined its expression status on the plasma membrane. Cotransfection of Bsg expression vectors with two different tags clarified that Bsg forms homo-oligomers in a cis-dependent manner on the plasma membrane. If the disulfide bond of the more N-terminally located Ig-like domain was destroyed by mutations, Bsg could not form oligomers. In contrast, the mutations of the C-terminal Ig-like domain or N-glycosylation sites did not affect the association. The association of mouse and human Bsgs, which exhibit high homology in the transmembrane and intracellular domains but low homology in the extracellular domain, was very weak as compared with that within the same species, suggesting the importance of the extracellular domain in the association. If the extracellular domain of the human Ret protein was replaced with the N-terminal Ig-like domain of Bsg, the resulting chimera protein was associated with intact wild-type Bsg, but not if the C-terminal Ig-like domain, instead of the N-terminal one, of Bsg was used. No oligomer formation took place between the intact wild-type Ret and Bsg proteins. In conclusion, these data indicate that the N-terminal Ig-like domain is necessary and sufficient for oligomer formation by Bsg on the plasma membrane.Keywords: basigin; EMMPRIN; immunoglobulin superfamily; neurothelin; oligomer.Cell-surface proteins, such as the Ig superfamily, the cadherin superfamily and the integrin superfamily, play important roles in development by regulating cellular differentiation, adhesion and migration [1,2]. Supramolecular structure formation, such as oligomer formation, between these molecules plays crucial roles in exerting their functions. This has been documented by extensive studies of the Ig superfamily. NCAM participates in neural cell adhesion, which is mainly mediated by homophilic binding in a trans-dependent manner through its third Ig-like domain [3,4]. Homodimer formation of ICAM in a cis-dependent manner enhances its binding to a leukocyte b2-integrin [5]. Binding of fibroblast growth factor (FGF) to its receptor (FGFR) leads to dimer formation of FGFR (eventually a complex formation consisting of two FGF, two FGFR and a heparan sulfate chain), which is mediated mainly through homophilic binding at the second Ig-like domain of FGFR [6]. In addition to protein±protein interaction as mentioned above, protein±sugar interaction is also important. P0, a neural adhesion molecule implicated in myelination, harbors an N-glycosylation site, to which the major homophilic binding site is mapped [7]. NCAM and L1, another neural adhesion molecule, associate each other in a cis-dependent manner to reinforce L1 homophilic trans-interaction: in this case...

Dendritic/tumor fusion cell (FC) vaccine is an effective approach for various types of cancer but has not yet been standardized. Antitumor activity can be modulated by different mechanisms such as dendritic cell (DC) maturation state. This study addressed optimal strategies for FC preparations to enhance Ag-specific CTL activity. We have created three types of FC preparations by alternating fusion cell partners: 1) immature DCs fused with autologous colorectal carcinoma cells (Imm-FCs); 2) Imm-FCs followed by stimulation with penicillin-inactivated Streptococcus pyogenes (OK-432) (Imm-FCs/OK); and 3) OK-432-stimulated DCs directly fused to autologous colorectal carcinoma cells (OK-FCs). Both OK-FCs and Imm-FCs/OK coexpressed the CEA, MUC1, and significantly higher levels of CD86, CD83, and IL-12 than those obtained with Imm-FCs. Short-term culture of fusion cell preparations promoted the fusion efficiency. Interestingly, OK-FCs were more efficient in stimulating CD4+ and CD8+ T cells capable of high levels of IFN-γ production and cytolysis of autologous tumor or semiallogeneic targets. Moreover, OK-FCs are more effective inducer of CTL activation compared with Imm-FCs/OK on a per fusion cell basis. The pentameric assay confirmed that CEA- and MUC1-specific CTL was induced simultaneously by OK-FCs at high frequency. Furthermore, the cryopreserved OK-FCs retained stimulatory capacity for inducing antitumor immunity. These results suggest that OK-432 promotes fusion efficiency and induction of Ag-specific CTL by fusion cells. We conclude that DCs fused after stimulation by OK-432 may have the potential applicability to the field of antitumor immunotherapy and may provide a platform for adoptive immunotherapy in the clinical setting.

Background: Cyclooxygenase 2 (COX-2), the inducible form of prostaglandin G/H synthase, is associated with several human cancers including pancreatic adenocarcinoma. Pancreatic stellate cells (PSCs) play a central role in the intense desmoplasia that surrounds pancreatic adenocarcinoma. The present study examined COX-2 expression in PSCs. PSCs isolated from normal rats, were cultured and exposed to conditioned medium (CM) from the human pancreatic cell line, PANC-1.

These results indicate that E-PEG was safe, tolerable and speedy when compared ordinary pull-method PEG.

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