Cloning of a Second Dendritic Cell-associated C-type Lectin (Dectin-2) and Its Alternatively Spliced Isoforms

Abstract

Using a subtractive cDNA cloning strategy, we isolated previously five novel genes that were expressed abundantly by the murine dendritic cell (DC) line XS52, but not by the J774 macrophage line. One of these genes encoded a unique, DC-associated C-type lectin, termed “dectin-1.” Here we report the characterization of a second novel gene that was also expressed in a DC-specific manner. Clone 1B12 encoded a type II membrane-integrated polypeptide of 209 amino acids containing a single carbohydrate recognition domain motif in the COOH terminus. The expression pattern of this molecule, termed “dectin-2,” was almost indistinguishable from that for dectin-1; that is, both were expressed abundantly at mRNA and protein levels by the XS52 DC line, but not by non-DC lines, and both were detected in spleen and thymus, as well as in skin resident DC (i.e. Langerhans cells). Interestingly, reverse transcriptase-polymerase chain reaction and immunoblotting revealed multiple bands of dectin-2 transcripts and proteins suggesting molecular heterogeneity. In fact, we isolated additional cDNA clones encoding two distinct, truncated dectin-2 isoforms. Genomic analyses indicated that a full-length dectin-2 (α isoform) is encoded by 6 exons, whereas truncated isoforms (β and γ) are produced by alternative splicing. We propose that dectin-2 and its isoforms, together with dectin-1, represent a unique subfamily of DC-associated C-type lectins. Using a subtractive cDNA cloning strategy, we isolated previously five novel genes that were expressed abundantly by the murine dendritic cell (DC) line XS52, but not by the J774 macrophage line. One of these genes encoded a unique, DC-associated C-type lectin, termed “dectin-1.” Here we report the characterization of a second novel gene that was also expressed in a DC-specific manner. Clone 1B12 encoded a type II membrane-integrated polypeptide of 209 amino acids containing a single carbohydrate recognition domain motif in the COOH terminus. The expression pattern of this molecule, termed “dectin-2,” was almost indistinguishable from that for dectin-1; that is, both were expressed abundantly at mRNA and protein levels by the XS52 DC line, but not by non-DC lines, and both were detected in spleen and thymus, as well as in skin resident DC (i.e. Langerhans cells). Interestingly, reverse transcriptase-polymerase chain reaction and immunoblotting revealed multiple bands of dectin-2 transcripts and proteins suggesting molecular heterogeneity. In fact, we isolated additional cDNA clones encoding two distinct, truncated dectin-2 isoforms. Genomic analyses indicated that a full-length dectin-2 (α isoform) is encoded by 6 exons, whereas truncated isoforms (β and γ) are produced by alternative splicing. We propose that dectin-2 and its isoforms, together with dectin-1, represent a unique subfamily of DC-associated C-type lectins. dendritic cells amino acid(s) carbohydrate recognition domain macrophage mannose receptor hepatic lectins macrophage galactose/N-acetylgalactosamine-specific lectin DC immunoreceptor monoclonal antibody reverse transcriptase polymerase chain reaction nucleotide(s) murine Dendritic cells (DC)1 are far more potent than other antigen-presenting cells (e.g.macrophages and B cells) in their capacity to activate immunologically naive T cells, and DC are, indeed, responsible for initiating T cell-mediated immune responses to a variety of antigens (1.Banchereau J. Steinman R.M. Nature. 1998; 392: 245-252Crossref PubMed Scopus (12080) Google Scholar, 2.Hart D.N.J. Blood. 1997; 90: 3245-3287Crossref PubMed Google Scholar). Members of the DC family are distributed to virtually all the organs (except the brain), where they serve as tissue resident antigen-presenting cells, playing critical roles in presenting environmental, microbial, and tumor-associated antigens to the immune system. Several years ago, we developed stable DC lines from the mouse epidermis (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar). These lines, termed as the XS series, maintain many important features of skin resident DC, i.e. Langerhans cells, and they have provided a useful tool for the application of modern technologies for studying DC biology (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar, 4.Takashima A. Edelbaum D. Kitajima T. Shadduck R.K. Gilmore G.L. Xu S. Taylor R.S. Bergstresser P.R. Ariizumi K. J. Immunol. 1995; 154: 5128-5135PubMed Google Scholar, 5.Xu S. Ariizumi K. Edelbaum D. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 1018-1024Crossref PubMed Scopus (66) Google Scholar, 6.Kitajima T. Ariizumi K. Mohamadzadeh M. Edelbaum D. Bergstresser P.R. Takashima A. J. Immunol. 1995; 155: 3794-3800PubMed Google Scholar, 7.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 155: 5190-5197PubMed Google Scholar, 8.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Clin. Invest. 1996; 98: 142-147Crossref PubMed Scopus (86) Google Scholar, 9.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Immunol. 1996; 157: 3312-3316PubMed Google Scholar, 10.Yokota K. Ariizumi K. Kitajima T. Bergstresser P.R. Street N.E. Takashima A. J. Immunol. 1996; 157: 1529-1537PubMed Google Scholar, 11.Ariizumi K. Kitajima T. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 2137-2141Crossref PubMed Scopus (48) Google Scholar, 12.Mohamadzadeh M. Poltorak A.N. Bergstresser P.R. Beutler B. Takashima A. J. Immunol. 1996; 156: 3102-3106PubMed Google Scholar, 13.Mohamadzadeh M. Ariizumi K. Sugamura K. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1996; 26: 156-160Crossref PubMed Scopus (27) Google Scholar). Most recently, we employed the subtractive cDNA cloning strategy to identify genes that were expressed preferentially by DC. 2K. Ariizumi, G. L. Shen, S. Shikano, S. Xu, R. Ritter III, T. Kumamoto, D. Edelbaum, A. Morita, P. R. Bergstresser, and A. Takashima, submitted for publication. 2K. Ariizumi, G. L. Shen, S. Shikano, S. Xu, R. Ritter III, T. Kumamoto, D. Edelbaum, A. Morita, P. R. Bergstresser, and A. Takashima, submitted for publication. Briefly, we constructed a DC-specific cDNA library by subtracting cDNAs prepared from the XS52 DC line with excess amounts of mRNAs isolated from the J774 macrophage line. Following three rounds of screening of this library, we identified five novel genes that were expressed selectively by XS52 DC, but not by J774 macrophages. One of these genes encoded a type II membrane-associated polypeptide of 244 amino acids (aa) containing a single carbohydrate recognition domain (CRD) motif at the COOH-terminal end. This polypeptide was, therefore, designated as DC-associated C-type (Ca2+-dependent) lectin-1 or dectin-1. Dectin-1 mRNA was expressed in skin resident DC (from which the XS52 line was derived) as well as in spleen and thymus, the tissues known to contain relatively large numbers of DC.2 Although the physiological function of dectin-1 remains unknown at present, the identification of a novel, DC-associated lectin is of particular interest, because one of the characteristic features of DC is the expression of many C-type lectins (1.Banchereau J. Steinman R.M. Nature. 1998; 392: 245-252Crossref PubMed Scopus (12080) Google Scholar, 2.Hart D.N.J. Blood. 1997; 90: 3245-3287Crossref PubMed Google Scholar). For example, DC express DEC-205, a type I membrane-integrated glycoprotein that contains 10 distinct CRD motifs in the extracellular region (14.Jiang W. Swiggard W.J. Heufler C. Peng M. Mirza A. Steinman R.M. Nussenzweig M.C. Nature. 1995; 375: 151-155Crossref PubMed Scopus (793) Google Scholar). DC also express a macrophage mannose receptor (MMR), which is a type I membrane-associated glycoprotein with 8 CRD motifs (15.Sallusto F. Cella M. Danieli C. Lanzavecchia A. J. Exp. Med. 1995; 182: 389-400Crossref PubMed Scopus (2159) Google Scholar). With respect to function, currently available data suggest that both DEC-205 and MMR mediate the uptake of glycosylated antigens by DC (1.Banchereau J. Steinman R.M. Nature. 1998; 392: 245-252Crossref PubMed Scopus (12080) Google Scholar, 2.Hart D.N.J. Blood. 1997; 90: 3245-3287Crossref PubMed Google Scholar, 15.Sallusto F. Cella M. Danieli C. Lanzavecchia A. J. Exp. Med. 1995; 182: 389-400Crossref PubMed Scopus (2159) Google Scholar, 16.Taylor M.E. Bezouska K. Drickamer K. J. Biol. Chem. 1992; 267: 1719-1726Abstract Full Text PDF PubMed Google Scholar). Unlike DEC-205 and MMR, which contain multiple CRD motifs in the NH2-terminal ends, the second group of C-type lectins consists of the polypeptides that contain a single CRD in their COOH termini. Members of this group include: (a) hepatic lectins (HL) (or asialoglycoprotein receptors), (b) macrophage galactose/N-acetylgalactosamine-specific lectin (MGL), (c) CD23 (low affinity Fcε receptor), and (d) various receptors encoded in the natural killer gene complex (e.g. CD69, CD94, NKR-P1, Ly-49, and NKG2) (17.Weis W.I. Taylor M.E. Drickamer K. Immunol. Rev. 1998; 163: 19-34Crossref PubMed Scopus (867) Google Scholar, 18.Brown M.G. Scalzo A.A. Matsumoto K. Yokoyama W.M. Immunol. Rev. 1997; 155: 53-65Crossref PubMed Scopus (147) Google Scholar). Of these type II surface lectins, DC are known to express CD23 (19.Bieber T. Rieger A. Neuchrist C. Prinz J.C. Rieber E.P. Boltz-Nitulescu G. Scheiner O. Kraft D. Ring J. Stingl G. J. Exp. Med. 1989; 170: 309-314Crossref PubMed Scopus (173) Google Scholar) and CD69 (20.Bieber T. Rieger A. Stingl G. Sander E. Wanek P. Strobel I. J. Invest. Dermatol. 1992; 98: 771-776Crossref PubMed Scopus (35) Google Scholar). More recently, Bates et al. E. J. I. S. S. P. S. J. Immunol. 163: Google Scholar) identified a novel, DC-associated type II surface lectin, termed DC immunoreceptor In we that DC express both type I surface lectins and and type II surface lectins CD69, and In this we have identified of the DC-associated type II surface lectin and were in the of the at the of the were to the of the of tissue of dectin-2 mRNA and were by XS52 cells are a DC line from the epidermis of (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar). This line was and in with mouse and as a of (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar, 4.Takashima A. Edelbaum D. Kitajima T. Shadduck R.K. Gilmore G.L. Xu S. Taylor R.S. Bergstresser P.R. Ariizumi K. J. Immunol. 1995; 154: 5128-5135PubMed Google Scholar). features of this DC line are (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar, 4.Takashima A. Edelbaum D. Kitajima T. Shadduck R.K. Gilmore G.L. Xu S. Taylor R.S. Bergstresser P.R. Ariizumi K. J. Immunol. 1995; 154: 5128-5135PubMed Google Scholar, 5.Xu S. Ariizumi K. Edelbaum D. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 1018-1024Crossref PubMed Scopus (66) Google Scholar, 6.Kitajima T. Ariizumi K. Mohamadzadeh M. Edelbaum D. Bergstresser P.R. Takashima A. J. Immunol. 1995; 155: 3794-3800PubMed Google Scholar, 7.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 155: 5190-5197PubMed Google Scholar, 8.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Clin. Invest. 1996; 98: 142-147Crossref PubMed Scopus (86) Google Scholar, 9.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Immunol. 1996; 157: 3312-3316PubMed Google Scholar, 10.Yokota K. Ariizumi K. Kitajima T. Bergstresser P.R. Street N.E. Takashima A. J. Immunol. 1996; 157: 1529-1537PubMed Google Scholar, 11.Ariizumi K. Kitajima T. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 2137-2141Crossref PubMed Scopus (48) Google Scholar, 12.Mohamadzadeh M. Poltorak A.N. Bergstresser P.R. Beutler B. Takashima A. J. Immunol. 1996; 156: 3102-3106PubMed Google Scholar, 13.Mohamadzadeh M. Ariizumi K. Sugamura K. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1996; 26: 156-160Crossref PubMed Scopus (27) Google Scholar). The J774 macrophage line from was from and in in the of We also the line P. B. Google lines (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar, 4.Takashima A. Edelbaum D. Kitajima T. Shadduck R.K. Gilmore G.L. Xu S. Taylor R.S. Bergstresser P.R. Ariizumi K. J. Immunol. 1995; 154: 5128-5135PubMed Google Scholar, G. Xu S. Bergstresser P.R. Takashima A. J. Invest. Dermatol. 1995; Full Text PDF PubMed Scopus Google dendritic T cell line Takashima A. M. Bergstresser P.R. Nature. PubMed Scopus Google macrophage line and line provided by and B cell clones by and line cells were isolated from skin of two and for Langerhans cells by as previously K. Kitajima T. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 2137-2141Crossref PubMed Scopus (48) Google Scholar, Edelbaum D. A. Bergstresser P.R. K. Takashima A. J. Immunol. Google Scholar). Langerhans cells were from this by as K. Kitajima T. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 2137-2141Crossref PubMed Scopus (48) Google Scholar). DC-specific cDNA library was constructed by subtracting the cDNA library prepared from the XS52 DC line with excess amounts of mRNAs isolated from the J774 macrophage line, and this library was by and to identify the clones that were expressed selectively by the XS52 DC The 1B12 was one of the clones that were in the manner. additional clones encoding dectin-2 isoforms, the DC-specific library was by 1B12 as a was as previously K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: Google Scholar). Briefly, isolated from cell lines or mouse organs were a a and with the dectin-2 or cDNA was as K. Kitajima T. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 2137-2141Crossref PubMed Scopus (48) Google Scholar, K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: Google Scholar) by the and and and and The were and or by as K. Kitajima T. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 2137-2141Crossref PubMed Scopus (48) Google Scholar, K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: Google Scholar). protein of and the extracellular domain of dectin-2 was produced as the encoding extracellular domain of dectin-2 was and were to the at the and Using the and the was to of the in This was E. protein was from E. in 8 and relatively of the proteins were in a and this was to its carbohydrate Briefly, proteins were with and for with that were with or from was by the that were by the of the were by of of proteins in by of the proteins in One the were from these and B cell were prepared the W.M. W. in Scholar). were for the of to proteins in clones were by were from the of by by affinity XS52 DC were in 10 with with a for 10 at and the was and by for at In cell were prepared from cell lines in in by for 10 at cells were 6 with containing of the three dectin-2 cDNA were prepared These were by or and with or the was with and developed with mouse library in was with a full-length cDNA for dectin-2 were and in containing the with by Following a at were in and in The were at clones were isolated and by clones were was from of E. and a The was at for 10 and with of I and of and by were for at with and and the was in 10 and with and the was with and in Genomic were from the by and a containing exons, the were with and with a 1B12 cDNA The were from and a II and their were in the a subtractive cloning strategy DC line J774 macrophage we isolated five cDNA clones that were expressed selectively by XS52 DC and that encoded novel One of these clones encoded a termed dectin-1, which a single CRD motif in the COOH terminus. 1B12 in its in its amino revealed a polypeptide of type II membrane-integrated of a domain a domain and extracellular The amino encoded by 1B12 with to murine a DC-associated surface receptor E. J. I. S. S. P. S. J. Immunol. 163: Google Scholar). The 1B12 polypeptide also with other M. K. T. S. J. 1992; PubMed Scopus Google D. PubMed Scopus Google R. K. T. PubMed Scopus Google F. Eur. J. Immunol. PubMed Scopus Google and J. Immunol. Google Scholar). of these a single CRD motif at the COOH-terminal to the type II membrane-associated C-type lectin indicated by in the COOH-terminal region of the 1B12 polypeptide all the amino known to in the CRD motifs of many C-type lectins M. PubMed Scopus Google Scholar). we designated this polypeptide as DC-associated C-type or in the CRD domain in the dectin-2 polypeptide with the CRD in other C-type lectins, as CD69 and CD23 The of dectin-1 and dectin-2 was in the and the CRD domain of the CRD the function of indicated that dectin-2 is in the subfamily and the whereas dectin-1 to from subfamily many C-type lectins (e.g. CD94, Ly-49, and NKG2) that are encoded in the natural killer gene complex M.G. Scalzo A.A. Matsumoto K. Yokoyama W.M. Immunol. Rev. 1997; 155: 53-65Crossref PubMed Scopus (147) Google Scholar, J. Immunol. 1997; Google Scholar, E. M. Immunol. 1997; Full Text PDF PubMed Scopus Google contains the immunoreceptor motifs in the domain E. J. I. S. S. P. S. J. Immunol. 163: Google Scholar). other C-type lectins (e.g. CD23 and dectin-1 a immunoreceptor motif E. M. Immunol. 1997; Full Text PDF PubMed Scopus Google Scholar, M. Nature. 1989; PubMed Scopus Google Scholar) in the the immunoreceptor motif the immunoreceptor motif was in the relatively of In dectin-2 is a of the type II surface lectin family containing a single CRD motif and a region the in the COOH-terminal extracellular and motifs in the In we identified a dectin-2 mRNA of expressed by the XS52 DC line mRNA was in of the non-DC lines, two macrophage lines and three T cell lines and a B cell a line and a line The cell type was not because of the that the XS52 DC line was in the of and (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar, 4.Takashima A. Edelbaum D. Kitajima T. Shadduck R.K. Gilmore G.L. Xu S. Taylor R.S. Bergstresser P.R. Ariizumi K. J. Immunol. 1995; 154: 5128-5135PubMed Google because this line to express dectin-2 mRNA of these from and because its expression was not in the J774 macrophage line by to in dectin-2 mRNA was expressed abundantly in the spleen and thymus, tissues known to contain relatively large numbers of DC (1.Banchereau J. Steinman R.M. Nature. 1998; 392: 245-252Crossref PubMed Scopus (12080) Google Scholar, 2.Hart D.N.J. Blood. 1997; 90: 3245-3287Crossref PubMed Google Scholar). dectin-2 mRNA was not by in the the that the XS52 DC line was from this tissue (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar) and that this DC line skin resident DC cells) in many features (3.Xu S. Ariizumi K. Caceres-Dittmar G. Edelbaum D. Hashimoto K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 154: 2697-2705PubMed Google Scholar, 4.Takashima A. Edelbaum D. Kitajima T. Shadduck R.K. Gilmore G.L. Xu S. Taylor R.S. Bergstresser P.R. Ariizumi K. J. Immunol. 1995; 154: 5128-5135PubMed Google Scholar, 5.Xu S. Ariizumi K. Edelbaum D. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 1018-1024Crossref PubMed Scopus (66) Google Scholar, 6.Kitajima T. Ariizumi K. Mohamadzadeh M. Edelbaum D. Bergstresser P.R. Takashima A. J. Immunol. 1995; 155: 3794-3800PubMed Google Scholar, 7.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Immunol. 1995; 155: 5190-5197PubMed Google Scholar, 8.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Clin. Invest. 1996; 98: 142-147Crossref PubMed Scopus (86) Google Scholar, 9.Kitajima T. Ariizumi K. Bergstresser P.R. Takashima A. J. Immunol. 1996; 157: 3312-3316PubMed Google Scholar, 10.Yokota K. Ariizumi K. Kitajima T. Bergstresser P.R. Street N.E. Takashima A. J. Immunol. 1996; 157: 1529-1537PubMed Google Scholar, 11.Ariizumi K. Kitajima T. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1995; 25: 2137-2141Crossref PubMed Scopus (48) Google Scholar, 12.Mohamadzadeh M. Poltorak A.N. Bergstresser P.R. Beutler B. Takashima A. J. Immunol. 1996; 156: 3102-3106PubMed Google Scholar, 13.Mohamadzadeh M. Ariizumi K. Sugamura K. Bergstresser P.R. Takashima A. Eur. J. Immunol. 1996; 26: 156-160Crossref PubMed Scopus (27) Google Scholar). We dectin-2 mRNA expression in the epidermis a more in two dectin-2 mRNA were detected in cells isolated from The the with the molecular of whereas the of the at that epidermis contains and resident T cells, in to Langerhans cells the of the cell almost both for This with cell dectin-2 mRNA was detected by in the Langerhans XS52 line, but was from the line and the T cell line dectin-2 transcripts are expressed in the and skin resident DC to the of this that the expression of dectin-2 mRNA were almost indistinguishable from for dectin-1 we prepared a protein of a and the extracellular of This was produced in E. in and by affinity One of the multiple bands from to in the cell prepared from the XS52 DC line with the molecular as in these bands were detected in the isolated from the XS52 DC line Most of these bands were detected in the prepared from of the non-DC lines, B cell T and lines The two bands and in the from the B cell and detected by because the bands were also detected with the dectin-2 proteins are produced selectively by the XS52 DC line, at mRNA levels was of particular to proteins one or more carbohydrate of proteins the CRD were with and for the to that with or to to of these carbohydrate as by the that were by the not we detected molecular in and immunoblotting suggesting the of dectin-2 isoforms. This was by analyses of to of the dectin-2 in the to the at two with molecular from the XS52 DC line as well as from the The to the encoding the the the and a of the CRD two with the to the encoding the CRD two In all the bands of the the molecular with with and with all these the of a unique dectin-2 with the and a second with the cDNA clones encoding truncated dectin-2 we the DC-specific cDNA library DC J774 with the In fact, additional clones in with this the three of we the of these in these cDNA clones The group of cDNA clones the the of the molecular with all the three The second group of clones in molecular with the but not with the The group in with the but not with the The with the were also in the second and the than in the these we that at three dectin-2 (a) the encoding a full-length polypeptide (b) the second encoding a polypeptide with in a region from the domain to the CRD domain (β and (c) the encoding a polypeptide with the CRD domain the of the truncated dectin-2 isoforms, we clones and We identified the of in and in amino that the the domain for dectin-2 and the CRD domain for the We these cDNA clones in revealed a single of in the with the full-length dectin-2 we detected two bands of and with produced two bands of and these we that dectin-2 consists of at three (a) of 209 with the molecular of (b) with a in the domain as and and (c) with in the CRD as and by which a single cDNA the or isoform) produced two proteins with at this for the of three transcripts encoding isoforms, we and in of from the domain to the CRD in the full-length dectin-2 was to encoded by exons, with encoding in the encoding in the encoding in the and encoding the CRD The and the S. Rev. PubMed Google Scholar) were both in was from the of Interestingly, and 6 were in and we identified the motifs for and and 6 at both and where the was identified in these we that dectin-2 and isoforms are alternative splicing. In the we have identified a novel, DC-associated C-type lectin, termed which important features with dectin-1. both dectin-2 and dectin-1 a domain of a relatively a extracellular and a single CRD in the COOH termini. dectin-2 mRNA expression were indistinguishable from for dectin-1 that is, both were (a) at relatively levels in the XS52 DC line but not in other non-DC lines, (b) abundantly in spleen and thymus, and (c) in the cell (i.e. Langerhans cells). expression of dectin-2 and dectin-1 proteins also in the XS52 DC line the cell these the of dectin-2 and dectin-1 was relatively in the and the CRD dectin-2 and dectin-1 represent two DC-associated C-type lectins. in the DC have to express both type I surface lectins and and type II surface lectins CD69, and The three and to this of DC-associated C-type lectin The dectin-2 the of in the and the CRD to murine which was identified by Bates et al. E. J. I. S. S. P. S. J. Immunol. 163: Google Scholar) by data with a from the CRD motifs of and from in that the immunoreceptor motif in the domain of was from the relatively domain of Interestingly, dectin-2 also immunoreceptor which was identified in the domain of dectin-1. that dectin-1 and DC, whereas dectin-2 is available with respect to the natural that are by CD69, dectin-1, In this of the carbohydrate to (or to We these to suggest that dectin-2 unique carbohydrate or that dectin-2 have to with a second C-type lectin to affinity carbohydrate as for other type II lectins with single CRD motifs O. T. J. Biol. Chem. Full Text PDF PubMed Google Drickamer K. J. Biol. Chem. Full Text PDF PubMed Google Scholar). more is that dectin-2 polypeptide or CD23 to a polypeptide of carbohydrate of the D. B. P. E. R.S. Nature. 1989; PubMed Scopus Google that not serve as natural of all the that to the C-type lectin are to identify the by the DC-associated type II surface lectins and to their physiological One of the in this was the identification of two truncated isoforms of i.e. the with in the domain and the with the CRD In this the domain of CD69 to for K. A. O. M. J. T. 1995; PubMed Scopus Google whereas the CRD mediate the recognition of is to that the and isoforms of dectin-2 from the full-length in one or more one identify the and the function of dectin-2 this of isoforms by alternative for other of the type II surface lectin For example, et al. R. M. J. Immunol. 1995; PubMed Scopus Google Scholar) identified a truncated of CD23 from which the domain and a of the was by alternative splicing. was that the CD23 the domain serve as a CD23 receptor et al. E. J. Immunol. 1995; 154: Google Scholar) identified transcripts the the of a type II surface lectin expressed by B More recently, et al. T. K. R. T. K. S. T. K. T. 1998; PubMed Scopus Google Scholar) identified the of CD94, one of the natural type II surface lectins. In this the isoforms we identified in dectin-2 are unique in that they the domain or a of the CRD additional for molecular of type II surface lectins. In we that dectin-2 and its isoforms, together with other CD69, and a unique subfamily of type II surface lectins. The important of for the of DC-associated We Street and Mohamadzadeh for T cell clones and B cell We are also to for