Exodus-1/LARC/MIP-3 (SCYA 20) Robert Hromas* Indiana University Medical Center and the Walther Oncology Center, R4-202, The Indiana Cancer Research Institute, 1044 W. Walnut Street, Indianapolis, IN 46202, USA * corresponding author tel: 317-274-3589, fax: 317-274-0396, e-mail:
[email protected] DOI: 10.1006/rwcy.2001.11023.
SUMMARY Exodus-1/LARC/MIP-3 (SCYA 20) is a recently discovered CC (or ) chemokine. It is only distantly related to other CC chemokines, representing a unique structure among the family. With such a unique structure, it is not surprising that it has a unique function. It mediates chemotaxis of naõÈ ve dendritic cells and memory T cells via its receptor, CCR6. -Defensins have also been shown to stimulate chemotaxis through CCR6, thereby linking innate and acquired immunity to sites of local inflammation. Exodus-1/LARC/MIP3 has also been shown to inhibit the proliferation of normal and leukemic hematopoietic progenitors.
BACKGROUND
Discovery LARC was originally isolated by three groups simultaneously. Hieshima et al. (1997) used a partial expressed sequence tag (EST) fragment to probe a cDNA library to clone the full-length cDNA. Since they found it expressed in liver and in activated lymphocytes, they termed this gene LARC, for liver and activation-regulated chemokine. Another group isolated a full-length cDNA sequence for this gene from the EST database (Rossi et al., 1997). They called the gene macrophage inflammatory protein-3 , or MIP-3 . This nomenclature did not originate from the cellular source or the function of MIP-3 , but rather from its structural
Cytokine Reference
relationship to the CC chemokine family, of which MIP-1 was a founding member. We found the gene during a sequencing a cDNA library we had made from human diabetic pancreatic islet cells to catalogue islet-specific genes (Hromas et al., 1997). We found that a cluster of cDNA clones representing the same gene in this library had weak homology to the CC chemokine family. Since recombinant protein derived from this gene markedly stimulated lymphocyte migration, we termed it Exodus-1.
Alternative names This gene and protein has also been designated SCYA 20 (small inducible cytokine family A member number 20) by the Human Genome Nomenclature Committee. Given the multiplicity of alternative names derived from the different discoverers of this protein, we will refer to Exodus-1/LARC/MIP-3 as SCYA 20 for the rest of this chapter. It is referred to as SCYA 20 in the National Center for Biotechnology Information analytic databases.
GENE AND GENE REGULATION
Accession numbers GenBank: LARC: D86955 (Hieshima et al., 1997) MIP-3 : U77035 (Rossi et al., 1997) Exodus-1: U64197 (Hromas et al., 1997)
Copyright # 2001 Academic Press
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The Exodus-1 clone derived from human pancreatic islets differs from the other two in that it lacks a single codon at the end of the leader sequence (beginning at nucleotide 121 on the Exodus-1 cDNA sequence). This missing alanine residue probably results from an alternative splicing event.
Sequence The complete cDNA of the novel chemokine Exodus1 was 821 nucleotides in length. The LARC and MIP3 clones were slightly shorter. There is a consensus polyadenylation site at nucleotide position 786 in Exodus-1. The 30 untranslated sequence has a number of AAAU sequences that mediate mRNA stability in many cytokine genes. These sequences promote message degradation, and contribute to the short half-life of many cytokine transcripts, including chemokines. There is a short 50 untranslated region of 43 nucleotides which contains an inframe translational stop codon. The sequence 50 of the ATG that initiates translation fits the Kozak consensus at the first three positions preceding the ATG, but none prior to that. The nucleotide after the ATG does not match the Kozak consensus.
Chromosome location The chromosomal location of SCYA 20 is 2q33±37 (Hieshima et al., 1997). There are no known human genetic diseases that map to this location. There are also no other known chemokines in this region. This is unusual for chemokines, which tend to cluster in homologous groups in specific regions of a given chromosome. This correlates with the finding that SCYA 20 binds a single specific chemokine receptor. Many of the chemokine groupings within chromosomal regions share promiscuous receptors which bind to many chemokines within that region. Tanaka et al. (1999) described the genomic structure of the murine SCYA 20 gene. Consistent with other CC chemokines, the gene has four exons and three introns. The 50 noncoding region contains consensus TAT and CAAT boxes but no other known regulatory elements.
Description of protein There are 95 amino acids in the conceptual translation of Exodus-1. LARC and MIP-3 have a single added alanine, and thus have 96 amino acids. This is consistent with most other members of the CC chemokine family. The first 26 amino acids fit the consensus for a signal peptide. Hieshima et al. (1997) produced LARC in a baculovirus system, and peptide sequenced the Nterminus. They showed that indeed the mature secreted protein starts at position 27 in LARC. Because of the alternative splicing mentioned above, the mature Exodus-1 protein begins at position 26 in Exodus-1, and lacks the initial alanine seen in MIP-3 and LARC. This protein may not be as active as the one with alanine at its N-terminus (Tanaka et al., 1999). The four cysteines that participate in the disulfide bonds that define this family are also conserved in SCYA 20 as are five highly conserved residues. SCYA 20 is most closely related to MIP-1 and RANTES at the amino acid level, with 26±28% identity, and 75% similarity when conservative changes are taken into account. SCYA 20 is especially similar to RANTES from amino acids 24 to 46 and again from 58 to 75 (numbering from the initiating methionine in Exodus1), where between these positions there are only six nonconservative changes. While SCYA 20 has many of the conserved amino acid features of the other human CC chemokines, SCYA 20 has several unusual characteristics. It has a highly basic C-terminus, more consistent with the MCP subfamily. In addition, SCYA 20 lacks the conserved tyrosine and threonine at positions 47 and 51, respectively, that are present in all other human CC chemokines. It is not clear if these two highly conserved amino acids play a role in CC chemokine activity since they are not predicted to be in contact with the receptor (Clore and Gronenborn, 1997). When compared with the other CC chemokines, SCYA 20 has one to three additional amino acids in this region between cysteines 2 and 3. These additional residues may compensate for the lack of the conserved amino acids at those sites.
Discussion of crystal structure
PROTEIN
The crystal structure has not been published, although it is likely that the SCYA 20 structure will not deviate too far from the previously published structures of other CC chemokines (Clore and Gronenborn, 1997).
Accession numbers
Posttranslational modifications
The amino acid sequences of SCYA 20 can be found at the same GenBank accession numbers listed above.
There are no known functional posttranslational modifications of SCYA 20. Indeed, purified peptide
Exodus-1/LARC/MIP-3 (SCYA 20) 3 synthesized entirely in vitro works as well as protein produced from a baculovirus system (Hromas et al., 1997).
CELLULAR SOURCES AND TISSUE EXPRESSION
Cellular sources that produce SCYA 20 was expressed by northern analysis in lymph nodes, peripheral blood leukocytes, thymus, and appendix (Rossi et al., 1997; Hromas et al., 1997). It was not expressed in the spleen or bone marrow. When a variety of nonlymphoid tissues are assessed, SCYA 20 is expressed only in lung (Hromas et al., 1997) and perhaps in the liver (Hieshima et al., 1997). It was not expressed in a number of cell lines tested, including TMR323 neuroblastoma, MDA breast carcinoma, K562 erythroleukemia, Jurkat T cell leukemia, HL60 promyelocytic leukemia, HL60 cells differentiated to granulocytes with retinoic acid, 3T3 embryonic fibroblasts, or 293 embryonic kidney cells (Hromas et al., 1997). Since the expression of many chemokines is induced in mononuclear cells by inflammatory stimuli, the expression of SCYA 20 after LPS, TNF , or PMA exposure was analyzed by northern analysis (Hromas et al., 1997). When peripheral blood mononuclear cells were exposed to LPS for 12 hours SCYA 20 expression was highly induced. This expression declined after 24 hours of exposure to LPS. When umbilical vein endothelial cells were exposed to TNF for just three hours, SCYA 20 expression was again highly induced. Significantly, SCYA 20 expression stayed high as long as there was an inflammatory stimuli present. When the monocytic leukemia cell line THP1 was treated with PMA the expression of SCYA 20 was also induced, reaching its peak at 48 hours after exposure, and declining slightly thereafter. Tanaka et al. (1999) found that SCYA 20 expression was induced in the monocytoid cell line J774 by LPS but not TNF , IFN , IL-1 , or IL-4. They also found that SCYA 20 was expressed highly in the epithelium around lymphoid tissue and intestines by in situ RNA hybridization. They hypothesize that it may play a role in stimulating migration of lymphocytes to form Peyer's patches.
RECEPTOR UTILIZATION Several groups isolated the receptor for SCYA 20. Since it was the sixth CC chemokine receptor identified, it was termed CCR6.
Baba et al. (1997) examined SCYA 20 binding to five known and five orphan CC receptors, attempting to identify the SCYA 20 receptor. SCYA 20 bound only to CCR6 with an induction of calcium flux. This binding had a Kd of 0.9 nM, within the range of other chemokine receptor±ligand interactions. This same group used alkaline phosphatase-SCYA 20 protein to show by Scatchard analysis that there were 2100 CCR6 receptors/cell on lymphocytes (Hieshima et al., 1997). Power et al. (1997) used degenerate oligonucleotides to conserved regions of chemokine receptors to PCR amplify a candidate receptor from lung dendritic cells. This candidate receptor (CCR6) bound SCYA 20, and led to pertussis toxin- and phospholipase C-dependent intracellular calcium mobilization. Liao et al. (1997) tested the ability of SCYA 20 to induce calcium flux in 293 cells transfected with orphan chemokine receptors. They showed that only CCR6 mediated SCYA 20-induced calcium mobilization. Later they analyzed the surface expression of CCR6 and found it to be on differentiated, resting memory T cells, B cells, and immature dendritic cells (Liao et al., 1999). Greaves et al. (1997) isolated CCR6 from CD34+ cord blood-derived dendritic cells, and showed that it mediated chemotaxis to SCYA 20. Varona et al. (1998) isolated the murine CCR6 homolog, and showed that it also mediated SCYA 20 chemotaxis. Of great interest was the recent report that CCR6 also bound -defensins (Yang et al., 1999b). Defensins are a family of very small peptides (around 4 kDa) primarily produced by epithelial cells in response to inflammatory stimuli. They can disrupt the cytoplasmic wall of some microorganisms. As such, they play an important role in innate, local defense against invading pathogenic microbes. Defensins were found to bind to CCR6 and mediate chemotaxis of immature dendritic cells and resting memory T cells. Therefore, CCR6 serves as a link between innate and acquired immunity, presumably by bringing antigen-presenting cells (dendritic cells) and antigen-responsive cells (T cells) to regions where microbial invasion is occurring.
IN VITRO ACTIVITIES
In vitro findings Hematopoietic Inhibition Like several other CC chemokines SCYA 20 also inhibited hematopoietic progenitor colony formation in a dose-dependent manner (Hromas et al., 1997).
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Increasing concentrations of pure synthetic SCYA 20 resulted in hematopoietic progenitor inhibition. SCYA 20 inhibitory activity plateaus at 50 ng/ml, at which there was also a statistically significant decrease in CFU-GM (49% of control), BFU-E (43% of control), and CFU-GEMM (43% of control). We used MIP-1 and IL-8 as positive inhibitory controls. At 100 ng/ml of recombinant human MIP-1 or IL-8, a dose at which their biological effect plateaus, there was a statistically significant reduction of CFU-GM (48% proliferation as compared to medium control for MIP-1 and 49% for IL-8), BFU-E (45% of control for both), and CFU-GEMM (49% of control for both). The effect of SCYA 20 on the proliferation of cytokine dependent myeloid cell lines was also tested (Hromas et al., 1997). The human myeloid cell line MO7E requires GM-CSF and SCF for maximal proliferation. When synthetic pure human SCYA 20 is added to the log phase MO7E cells, in the presence of GM-CSF and SCF, proliferation over the next 72 hours is reduced to 10.4% of control. It should be noted that this was not a cytotoxic effect, as the SCYA 20-treated cells had greater than 95% viability at every time point, identical to that of the control cells. Next, we tested whether SCYA 20 could inhibit the proliferation of hematopoietic progenitors from chronic myelogenous leukemia (CML) (Hromas et al., 2000). Bone marrow from two CML patients in the chronic phase that had not received any treatment with IFN was tested for inhibition of hematopoietic progenitor proliferation by various concentrations of synthetic purified SCYA 20 (in this case, Exodus-1 protein). MIP-1 at concentrations from 1.25 ng/mL to 500 ng/mL did not have any inhibitory effect on the proliferation of CML progenitors from these two patients, in contrast to the inhibition seen with MIP1 in normal progenitors. However, SCYA 20 showed a dose-dependent inhibition of CML CFUGM, BFU-E, and CFU-GEMM progenitor proliferation for both patients beginning at 12.5 ng/mL. When both patients are taken into account, this inhibitory response leveled off between 50 and 100 ng/ mL. Therefore, we chose 100 ng/mL as the concentration of SCYA 20 to obtain maximal response in all progenitor assays for more extensive studies. Bone marrow was obtained from 13 additional CML patients in the chronic phase who were not currently being treated with IFN . The effect of MIP1 on CML progenitor cell proliferation was tested. MIP-1 inhibits normal marrow progenitor cell proliferation, but is most often inactive on CML progenitors (Hromas et al., 2000). As expected,
MIP-1 did not inhibit progenitor proliferation in 11 of the 13 CML samples. However, in two samples MIP-1 inhibited progenitor proliferation. (Average percentage inhibition for these two samples compared with untreated control: CFU-GM- 43%, BFU-E37%, CFU-GEMM-50%). In contrast, all 13 CML samples had progenitor proliferation that was significantly inhibited by SCYA 20 (p < 0.01). CFU-GM were inhibited by an average of 53%, BFU-E an average of 47%, and CFU-GEMM an average of 52% (Hromas et al., 2000). Thus, CML progenitor proliferation from every patient tested was significantly inhibited by SCYA 20. SCYA 20 was markedly more effective than MIP-1 at inhibiting CML progenitor proliferation. Chemotaxis SCYA 20 is a potent mediator of lymphocyte chemotaxis. It appears to be most active on T cells, although it can attract a number of other cell types. It shares an Asp-Cys-Cys-Leu sequence about its N-terminus with the CCR7 ligands Exodus-2/SLC/6Ckine and Exodus3/MIP-3 /ELC. These CCR7 chemokines also share similar chemotactic properties, such as preferentially attracting T cells, although they differ in the T cell subsets that are preferentially attracted. SCYA 20 attracts CD45RO+ memory T cells about twice as well as RA+ T cells (Christopherson et al., 1999). In addition, CD4+ T cells were found to be attracted approximately twice as well as CD8+ T cells. It should be noted however, that SCYA 20 CD8+ T cells and CD45RA+ T cells will still migrate in response to SCYA 20.
T cells, found in Peyer's patches in the intestinal epithelium, where SCYA 20 is highly expressed, are also attracted well by SCYA 20 (Tanaka et al., 1999). However, T cells were not chemoattracted well by SCYA 20. IgM+/IgD- naõÈve B cells are also chemoattracted by SCYA 20 (Tanaka et al., 1999). A recent study has found that immature CD34derived dendritic cell migration is stimulated by SCYA 20 (Dieu et al., 1998). This report failed to see either CCR6 expression or chemotaxis to SCYA 20 in monocyte-derived dendritic cells. However, another report found that if dendritic cells were derived from monocytes in the presence of TGF that CCR6 was then expressed, and these dendritic cells now migrated in response to SCYA 20 (Yang et al., 1999a). It was reported that as CD34-derived dendritic cells matured they lost CCR6 expression and responsiveness to SCYA 20, and gained responsiveness to the CCR7 ligands mentioned above. We and another group found that SCYA 20 could also stimulate the migration of activated but not
Exodus-1/LARC/MIP-3 (SCYA 20) 5 resting human NK cells, although not nearly as well as the CCR7 ligands (Robertson et al., 2000; Al-Aoukaty et al., 1998). There is one report that SCYA 20 can stimulate a low-level eosinophil migration via CCR6 (Sullivan et al., 1999). This migration was pertussis toxinsensitive. This study also found that the p42/44 MAP kinase was phosphorylated, albeit at a low level, and it was postulated that it might play a part in mediating this chemotaxis. Adhesion The mechanism of the arrest of vascular T cell rolling along endothelial cells has been recently defined. Campbell et al. (1998) found that SCYA 20 stimulates adhesion to ICAM-1 by rolling CD4+ memory T cells. SDF-1 and the CCR7 ligands stimulated adhesion of both naõÈve and memory T cells.
IN VIVO BIOLOGICAL ACTIVITIES OF LIGANDS IN ANIMAL MODELS
Normal physiological roles The normal in vivo physiologic role of SCYA 20 can be postulated from the above studies in vitro. However, there are no publications describing the normal physiologic role of SCYA 20 in vivo.
Species differences There have been no published studies that delineate any species differences for SCYA 20. Thus far, it appears that the murine and human protein function the same.
Knockout mouse phenotypes There are no knockout mice for SCYA 20 yet described.
Pharmacological effects SCYA 20 may be able to serve as a protective agent for marrow toxicity from cytotoxic chemotherapy based on the above studies. In addition, it may have
therapeutic benefit in chronic myelogenous leukemia, based on the above studies.
PATHOPHYSIOLOGICAL ROLES IN NORMAL HUMANS AND DISEASE STATES AND DIAGNOSTIC UTILITY
Normal levels and effects We originally isolated SCYA 20 from human diabetic pancreatic islet cells (Hromas et al., 1997). In early diabetes there is an autoimmune T cell response against islet cells. This response is thought to occur because of crossreaction between a viral antigen from a previous infection and an islet cell antigen. Therefore, it is possible that SCYA 20 plays a role in mediating the migration of memory T cells against a particular viral antigen into the islets. Perhaps interfering with SCYA 20 early in the course of juvenile-onset diabetes may decrease the morbidity of that disease. Kleeff et al. (1999) found that pancreatic tumors markedly overexpressed SCYA 20 as compared with normal pancreatic tissue. They also found that the lymphocytic tumor infiltrate expressed CCR6. These data indicate that gene therapy strategies using SCYA 20 as a tumor vaccine may be effective in stimulating an immune response against the malignancy. The advantage of this gene therapy strategy is that the antitumor response is likely to be systemic even if gene transfer was local. SCYA 20 may also play a key role in the T cell infiltrative skin diseases. SCYA 20 is highly expressed in epithelium. It is chemoattractive for memory T cells. There are a number of skin diseases, such as mycosis fungoides, lichen planus, atopic dermatitis, and graft-versus-host disease, where memory T cells pathologically migrate to and destroy dermal tissue. Interfering with SCYA 20 in these diseases may decrease their morbidity. Based on the above data, that SCYA 20 markedly inhibits the proliferation of chronic myeloid leukemia progenitors, it is also possible that SCYA 20 may have therapeutic potential in treating CML. Since much of the early morbidity of CML is from the pancytosis seen in this disease, reducing that hyperproliferation may benefit patients. It would be especially interesting to use SCYA 20 in conjunction with IFN in treating CML to assess whether it could increase the number of cytogenetic responders (Hromas et al., 2000).
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Role in experiments of nature and disease states In Acquired and Innate Immunity Compiling the data reviewed here, a model for the generation of an immune response against an invading pathogen can be synthesized. Local inflammatory stimuli such as LPS from the microbe or TNF from the damaged epithelial cells stimulate the secretion of SCYA 20 and -defensins. -Defensins not only are a local inhibition to microbial growth, but also assist in initiating the immune response cascade. SCYA 20 and the -defensins chemoattract immature dendritic cells and memory T cells to the region of infection via interaction with CCR6. The immature dendritic cells process antigen, and mature. Upon maturation they stop expressing CCR6, which releases them from the local chemotactic gradient, and begin expressing CCR7, which stimulates their migration to regional lymph nodes which are expressing Exodus-2/SLC/ 6Ckine and Exodus-3/MIP-3 /ELC, the ligands for CCR7. Within the regional nodes, these mature dendritic cells present antigen to naõÈ ve T cells, also expressing CCR7, and drawn to that locale by the CCR7 ligands expressed by the dendritic cells themselves, and also by node high endothelial venules of the lymph node. The naõÈ ve T cells mature upon this antigen presentation, and become relatively more responsive to CCR6, thereby becoming sensitive to the chemotactic gradient back to the original region of microbial invasion. This amplification of the acquired immune response relies of the initial expression of SCYA 20 in the region of inflammation.
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Dieu, M. C., Vanbervliet, B., Vicari, A., Bridon, J. M., Oldham, E., Ait-Yahia, S., Briere, F., Zlotnik, A., Lebecque, S., and Caux, C. (1998). Selective recruitment of immature and mature dendritic cells by distinct chemokines expressed in different anatomic sites. J. Exp. Med. 188, 373±386. Greaves, D. R., Wang, W., Dairaghi, D. J., Dieu, M. C., Saint-Vis, B., Franz-Bacon, K., Rossi, D., Caux, C., McClanahan, T., Gordon, S., Zlotnik, A., and Schall, T. J. (1997). CCR6, a CC chemokine receptor that interacts with macrophage inflammatory protein 3alpha and is highly expressed in human dendritic cells. J. Exp. Med. 186, 837±844. Hieshima, K., Imai, T., Opdenakker, G., Van Damme, J., Kusuda, J., Tei, H., Sakaki, Y., Takatsuki, K., Miura, R., Yoshie, O., and Nomiyama, H. (1997). Molecular cloning of a novel human CC chemokine liver and activation-regulated chemokine (LARC) expressed in liver. Chemotactic activity for lymphocytes and gene localization on chromosone 2. J. Biol. Chem. 272, 5846±5853. Hromas, R., Gray, P. W., Chantry, D., Godiska, R., Krathwohl, M., Fife, K., Bell, G. I., Takeda, J., Aronica, S., Gordon, M., Cooper, S., Broxmeyer, H. E., and Klemsz, M. J. (1997). Cloning and characterization of exodus, a novel betachemokine. Blood 89, 3315±3322. Hromas, R., Cripe, L., Hangoc, G., Cooper, S., and Broxmeyer, H. E. (2000). The exodus subfamily of CC chemokines inhibits the proliferation of chronic myelogenous leukemia progenitors. Blood 95, 1506±1508. Kleeff, J., Kusama, T., Rossi, D. L., Ishiwata, T., Maruyama, H., Friess, H., Buchler, M. W., Zlotnik, A., and Korc, M. (1999). Detection and localization of Mip-3alpha/LARC/Exodus, a macrophage proinflammatory chemokine, and its CCR6 receptor in human pancreatic cancer. Int. J. Cancer 81, 650±657. Liao, F., Alderson, R., Su, J., Ullrich, S. J., Kreider, B. L., and Farber, J. M. (1997). STRL22 is a receptor for the CC chemokine MIPI-3alpha. Biochem. Biophys. Res. Commun. 236, 212±217. Liao, F., Rabin, R. L., Smith, C. S., Sharma, G., Nutman, T. B., and Farber, J. M. (1999). CC-chemokine receptor 6 is expressed on diverse memory subsets of T cells and determines responsiveness to macrophage inflammatory protein 3 alpha. J. Immunol. 162, 186±194. Power, C. A., Church, D. J., Meyer, A., Alouani, S., Proudfoot, A. E., Clark-Lewis, I., Sozzani, S., Mantovani, A., and Wells, T. N. (1997). Cloning and characterization of a specific receptor for the novel CC chemokine MIP-3alpha from lung dendritic cells. J. Exp. Med. 186, 825±835. Robertson, M., Willaims, B., Christopherson, K II, Brahmi, Z., and Hromas, R. (2000). Regulation of human natural killer cell migration by the Exodus family of CC chemokines. Cell. Immunol. 199, 8±14. Rossi, D. L., Vicari, A. P., Franz-Bacon, K., McClanahan, T. K., and Zlotnik, A. (1997). Identification through bioinformatics of two new macrophage proinflammatory human chemokines: MIP-3alpha and MIP-3beta. J. Immunol. 158, 1033±1036. Sullivan, S. K., McGrath, D. A., Liao, F., Boehme, S. A., Farber, J. M., and Bacon, K. B. (1999). MIP-3alpha induces human eosinophil migration and activation of the mitogen-activated protein kinases (p42/p44 MAPK). J. Leukoc. Biol. 66, 674±682. Tanaka, Y., Imai, T., Baba, M., Ishikawa, I., Uehira, M., Nomiyama, H., and Yoshie, O. (1999). Selective expression of liver and activation-regulated chemokine (LARC) in intestinal epithelium in mice and humans. Eur. J. Immunol. 29, 633±642. Varona, R., Zaballos, A., Gutierrez, J., Martin, P., Roncal, F., Albar, J. P., Ardavin, C., and Marquez, G. (1998). Molecular
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LICENSED PRODUCTS R & D (Minneapolis, MN) produces murine and human SCYA 20 protein under the name MIP-3 . They also produce antisera against CCR6.
Research Diagnostics, Inc. (Flanders, NJ) produces human SCYA 20 protein under the name of MIP-3 . They also produce antisera against CCR6. Torrey Pines Biolabs (La Jolla, CA) produces antisera against SCYA 20 under the name anti-LARC. New England Nuclear Labs (Boston, MA) produces an I125-labeled SCYA 20 protein under the name of MIP-3 . There are no FDA-approved therapeutic modalities.
