Biomedical subjects

A Minty

Publications and source records attributed to A Minty.

At least 37 records · Page 2Linked to original sources

PubMed1995

The insulin receptor substrate-1-related 4PS substrate but not the interleukin-2R gamma chain is involved in interleukin-13-mediated signal transduction.

Interleukin-13 (IL-13) induced a potent mitogenic response in IL-3-dependent TF-1 cells and DNA synthesis to a lesser extent in MO7E and FDC-P1 cells. IL-13 stimulation of these lines, like IL-4 and insulin-like growth factor-1 (IGF-1), resulted in tyrosine phosphorylation of a 170-kD substrate. The tyrosine-phosphorylated 170-kD substrate strongly associated with the 85-kD subunit of phosphoinositol-3 (PI-3) kinase and with Grb-2. Anti-4PS serum readily detected the 170-kD substrate in lysates from both TF-1 and FDC-P1 cells stimulated with IL-13 or IL-4. These data provide evidence that IL-13 induces tyrosine phosphorylation of the 4PS substrate, providing an essential interface between the IL-13 receptor and signaling molecules containing SH2 domains. IL-13 and IL-4 stimulation of murine L cell fibroblasts, which endogenously express the IL-4 receptor (IL-4R alpha) and lack expression of the IL-2 receptor gamma subunit (IL-2R gamma), resulted in tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1)/4PS. Enhanced tyrosine phosphorylation of IRS-1/4PS was observed in response to IL-4, but not IL-13 treatment of L cells transfected with the IL-2R gamma chain. These results indicate that IL-13 does not use the IL-2R gamma subunit in its receptor complex and that expression of IL-2R gamma enhances, but is not absolutely required for mediating IL-4-induced tyrosine phosphorylation of IRS-1/4PS.

Adaptor Proteins, Signal Transducing↗

PubMed1995

Interleukin-13 selectively suppresses the growth of human macrophage progenitors at the late stage.

Interleukin-13 (IL-13) is a pleiotropic cytokine that inhibits the production of inflammatory cytokines of monocytes. We investigated the effects of IL-13 on the clonal growth of human hematopoietic progenitors. IL-13 alone did not support any colony formation. IL-13 markedly suppressed macrophage colonies that were formed in the presence of IL-3 and erythropoietin, granulocyte-macrophage colony-stimulating factor, or macrophage colony-stimulating factor. Macrophage colony cells showed dendritic cell-line morphology and cellular aggregates. IL-13 did not affect granulocyte colony and erythroid burst formation. Delayed addition of IL-13 and replating onto the culture dishes with IL-13 showed that macrophage colony formation was suppressed during days 8 and 14 of culture. These results indicate that IL-13 affects the growth of the late stage of committed macrophage progenitors. Single-cell culture of isolated CD34+CD33+ cells with IL-13 confirmed that macrophage colony formation was significantly suppressed. These results show that IL-13 directly suppresses the proliferation of differentiating macrophages. In addition, these suppressive effects of IL-13 were synergistic with IL-4. Furthermore, in the liquid culture of bone marrow cells in the presence of IL-13, the number of CD14 (monocyte-macrophage antigen)-positive cells decreased and CD18 (LFA-1 beta)-positive cells increased. It is concluded that IL-13 affects the growth of the late stage of macrophage precursors as well as mature monocytes. Induction of differentiation of human monocytes may be correlated with the suppression of their progenitors.

Bone Marrow Cells↗

PubMed1995

Isolation of an IL-13-dependent subclone of the B9 cell line useful for the estimation of human IL-13 bioactivity.

A novel sub-clone of the B9 hybridoma cell line (B9-1-3) has been selected by cloning following continuous culture in rhIL-13. This cell line shows an increased sensitivity to both hIL-13 and mIL-4 compared to the parental B9 cell line. The proliferative response to IL-13 can be blocked with an anti-IL-4 receptor monoclonal antibody but not with the soluble IL-4 receptor, suggesting that IL-13- and IL-4-binding receptor subunits are distinct but form part of a common receptor complex. Although the B9-1-3 cell line is still sensitive to picogrammes of IL-6, it can be used to measure IL-13 in the presence of IL-6 by inclusion of excess neutralizing IL-6 antibody. This cell line should thus prove useful both in measuring the IL-13 bioactivity and for the dissection of the molecular nature of the IL-13:IL-4 receptor complex.

Animals↗

PubMed1995

Function of the interleukin-2 (IL-2) receptor gamma-chain in biologic responses of X-linked severe combined immunodeficient B cells to IL-2, IL-4, IL-13, and IL-15.

The interleukin-2 (IL-2) receptor gamma-chain is a common component of several members of the cytokine receptor superfamily including those for IL-2, IL-4, IL-7, IL-9, IL-15, and possibly IL-13, and has recently been renamed the common gamma-chain (gamma c-chain). Transfection experiments have shown that the gamma c-chain participates in signal transduction by IL-2, IL-4 and IL-7, but a functional role for the gamma c-chain in biological responses by normal T cells and B cells to these cytokines has not been established. In this study, we have used X-linked severe combined immunodeficiency (X-SCID) as a naturally occurring gamma c-chain gene disruption model to examine the role of the gamma c-chain in human B-cell responses to IL-2, IL-4, IL-13, and IL-15. Our experiments show that B cells from two X-SCID patients with characterized gamma c-chain gene mutations do not respond to IL-2 or IL-15, but respond as well or better than normal B cells to both IL-4 and IL-13 in assays for B-cell activation, proliferation, and IgE secretion. This finding raises important questions about the function of the gamma c-chain in receptors for IL-4 and IL-13, and the nature of the immune defect in X-SCID.

B-Lymphocytes↗

PubMed1995

Differential effects of recombinant human interleukin-13 on the in vitro growth of human haemopoietic progenitor cells.

Effects of recombinant human interleukin (IL)-13 on in vitro haemopoiesis from non-adherent mononuclear cells (NAMC) or highly enriched CD34+ cells of human cord blood (CB) were studied. IL-13 significantly increased megakaryocyte (MK) colony formation from either NAMC or CD34+ cells cultured in a plasma clot system supplemented with aplastic anaemia serum (AAS) and phytohaemagglutinin-stimulated human peripheral blood leucocyte-conditioned medium (PHA-LCM) in a dose-dependent manner. Experiments using a modified plasma clot culture, in which normal AB serum and various cytokines were added to replace AAS and PHA-LCM, demonstrated an increased MK colony number in the presence of IL-13, especially in combination with IL-3. However, IL-13 had no stimulatory effect, but rather a slight inhibitory effect in some cases on granulocyte-macrophage (GM) colony formation in both plasma clot cultures. Furthermore, the growth of GM progenitor cells in a methylcellulose culture system in the presence of IL-3, GM-CSF, Epo, G-CSF or in combination was significantly inhibited by the addition of IL-13. On the other hand, high concentrations (100 ng/ml) of IL-13 were needed to cause a slight inhibition on the growth of BFU-E-derived colonies under the same methylcellulose culture. These results indicate that IL-13, alone and synergistically with the effect of IL-3, promotes MK colony formation, but it inhibits the growth of GM and erythroid progenitor cells in vitro.

Cells, Cultured↗

PubMed1994

Macrophage-inactivating IL-13 suppresses experimental autoimmune encephalomyelitis in rats.

Experimental autoimmune encephalomyelitis (EAE) is initiated by myelin basic protein (MBP)-specific CD4+ T cells of the Th1 phenotype that subsequently trigger the invasion of monocytes/macrophages into the brain. In this study, we evaluated the potential of human recombinant (hr) IL-13 to exert a protective effect on the development of EAE in Lewis rats. hrIL-13 is found to be a potent in vitro modulator of various rat macrophage functions, including an inhibition of the production of the proinflammatory cytokines IL-1 beta and TNF, and a simultaneous enhancement of MHC class II and CD4 receptor expression. Furthermore, hrIL-13 displayed a slight, but highly reproducible, inhibitory effect on the in vitro proliferative responses of encephalitogenic MBP-specific T cells stimulated in the presence of thymic APCs. Upon in vivo application of hrIL-13-secreting vector cells into MBP-immunized animals, the cytokine was capable of markedly suppressing the development of EAE, as assessed by a reduction of the mean duration, severity, and incidence of disease. This suppression of disease coincided with an only minimal reduction of MBP-directed T cell autoreactivity and no alteration in MBP-specific autoantibody production. We infer from these results that a strictly Th1-initiated immune disease can be attenuated efficiently by the administration of a cytokine that primarily targets cells of the macrophage/monocyte lineage and seems to exert no undesirable general suppression on either T cell or B cell immunoreactivity in vivo.

Animals↗

PubMed1994

Regulation of endothelial and mesothelial cell function by interleukin-13: selective induction of vascular cell adhesion molecule-1 and amplification of interleukin-6 production.

The present study was designed to explore the interaction of interleukin-13 (IL-13) with vascular endothelial cells (EC). In vitro exposure to IL-13 of human umbilical vein EC induced surface expression of vascular cell adhesion molecule-1 (VCAM-1). At optimal concentrations (10 to 50 ng/mL) and exposure times (24 hours), IL-13 was a twofold to threefold less effective inducer of VCAM-1 than IL-1, which was used as reference EC activator. When IL-13 was combined with IL-1, an almost additive induction of VCAM-1 was observed. Induction of VCAM-1 by IL-13 was selective in that E-selectin and intercellular adhesion molecule-1 (ICAM-1) were unaffected. IL-13 caused a modest reduction of IL-1 induction of E-selectin and ICAM-1. Surface expression of VCAM-1 on IL-13-treated cells was associated with mRNA induction (as assessed by Northern analysis and reverse transcriptase-polymerase chain reaction), with predominance of transcripts encoding the 7 Ig domain form of this molecule. In agreement with previous reports, IL-13 inhibited cytokine production in human monocytes. In contrast, IL-13 was a weak inducer and an amplifier (in concert with IL-1) of IL-6 expression in EC. Mesothelial cells, which share properties with EC and regulate the traffic and function of leukocytes in serosal cavities, were stimulated to express VCAM-1 and IL-6 by IL-13. Thus, IL-13 elicits a spectrum of responses in vascular endothelium remarkably similar to that of IL-4 and IL-10. Interaction of these cytokines with vascular endothelium may play an important role in the induction and expression of Th2-dependent responses.

Base Sequence↗

PubMed1994

Interleukin 13: novel role in direct regulation of proliferation and differentiation of primitive hematopoietic progenitor cells.

The recently cloned interleukin 13 (IL-13) shares most investigated biological activities on B lymphocytes and monocytes with IL-4. In this study we investigated for the first time the potential role of IL-13 in the regulation of the growth of hematopoietic progenitor cells. IL-13 enhanced stem cell factor (SCF)-induced proliferation of Lin-Sca-1+ bone marrow progenitor cells more potently than IL-4. The effect of IL-13 was purely synergistic, since IL-13 alone stimulated no colony formation. Single cell experiments suggested that the synergistic effect of IL-13 on Lin-Sca-1+ progenitors was directly mediated. In contrast, IL-13 had no synergistic activity on SCF-induced proliferation of the more mature Lin-Sca-1- progenitor cells. Thus, the cloning frequency in response to SCF + IL-13 was at least 20-fold higher in the Lin-Sca-1+ than the Lin-Sca-1- progenitor cell population. Furthermore, IL-13 but not IL-4 synergistically enhanced colony formation of Lin-Sca-1+ progenitors in response to granulocyte/macrophage colony-stimulating factor (GM-CSF) (threefold), whereas both IL-4 and IL-13 enhanced G-CSF-induced colony formation (threefold), and neither of the two significantly affected CSF-1 and IL-3-induced proliferation. Finally, whereas stimulation of Lin-Sca-1+ progenitors by SCF + G-CSF resulted in the formation of 90% granulocytes, the addition of IL-13 resulted in the production of macrophages exclusively. This novel effect on differentiation was directly mediated, shared with IL-4, and could not be observed on Lin-Sca-1- progenitor cells. Collectively, these findings indicate a novel role of IL-13 in early myelopoiesis, partially overlapping but also different from that of IL-4.

Animals↗

PubMed1994

Human interleukin-13 activates the interleukin-4-dependent transcription factor NF-IL4 sharing a DNA binding motif with an interferon-gamma-induced nuclear binding factor.

The effects of interleukin-13 (IL-13) and interleukin-4 (IL-4) on cellular functions were shown to be quite similar. We provide evidence that in monocytes as well as in T lymphocytes both IL-4 and IL-13 activate the same recently identified transcription factor NF-IL4 which binds to the specific responsive element IL-4RE. In addition, we show that a nuclear factor activated by interferon-gamma also interacts with the IL-4RE. It differs from NF-IL4 in the electrophoretic mobility of the complex with DNA, in its DNA-binding specificity and in the proteins interacting with the DNA sequence. Sensitivity against various enzyme inhibitors suggests that components of the signal transduction pathway are shared by all three cytokines.

Animals↗

PubMed1994

Interleukin-13 induces expression and release of interleukin-1 decoy receptor in human polymorphonuclear cells.

The aim of this study was to examine whether interleukin-13 (IL-13), a cytokine with anti-inflammatory activities, affected expression of interleukin-1 (IL-1) receptors (R) in human polymorphonuclear cells (PMN). Treatment with IL-13 augmented both type I and type II (decoy) R transcripts, with the latter being by far the most represented. The transcriptional inhibitor actinomycin D blocked the induction of IL-1 R mRNAs by IL-13. Nuclear run-off experiments demonstrated an augmented transcriptional rate of IL-1 decoy R in IL-13-treated B lymphoblastoid cells. The protein synthesis inhibitor cycloheximide blocked type I R expression but superinduced decoy R expression. IL-13 augmented the binding of radiolabeled IL-1 beta on the PMN surface with an increased number of IL-1 receptors and no change in Kd values. IL-13 induced the surface expression of IL-1 decoy R and the release by PMN of an IL-1-binding protein identified as a soluble version of the IL-1 decoy R. These results show that PMN is an important target for IL-13 and that induction of expression and release of the IL-1 decoy R, in concert with inhibition of cytokine synthesis, may represent an important mechanism by which IL-13 blocks IL-1, a central mediator of inflammatory reactions.

Blotting, Northern↗

PubMed1994

Interleukin-13 stimulates interleukin-6 production by human keratinocytes. Similarity with interleukin-4.

Interleukin-13 (IL-13) is a recently described human lymphokine which is produced by activated T-cells. Its effect on the production of IL-6 by normal keratinocytes and keratinocyte cell lines of human origin was studied and compared to that of IL-4. IL-13, similarly to IL-4, stimulated IL-6 expression by these cells in a dose- and time-dependent manner. Contamination with endotoxin was excluded by the use of polymyxin B and heat-inactivated cytokines. Further, we showed that IL-13, like IL-4, not only stimulated IL-6 production but also was able to induce overexpression of this cytokine in response to an inflammatory signal such as lipopolysaccharide (LPS). In a previous study, we demonstrated that IL-13, by inhibiting IL-6 and other cytokines produced by monocytes, exhibited an 'anti-inflammatory profile' comparable to that displayed by IL-4. In contrast, we show here that IL-13, by stimulating IL-6 production by keratinocytes, may favour the installation of an inflammatory process at a local level and, here again, it acted like IL-4. Therefore, according to the type of target cell these two 'TH2 type' cytokines induce similar opposing effects on IL-6 production and are likely to be important cytokines in the regulation of inflammation at both systemic and local levels.

Cell Line↗

PubMed1994

Interleukin-13 induces the production of interleukin-1 receptor antagonist (IL-1ra) and the expression of the mRNA for the intracellular (keratinocyte) form of IL-1ra in human myelomonocytic cells.

The aim of this study was to examine the expression of interleukin-1 receptor antagonist (IL-1ra) in human myelomonocytic cells treated with IL-13. IL-13 induced IL-1ra transcripts in human circulating monocytes and polymorphonuclear cells (PMN). Induction by IL-13 was not blocked, but rather superinduced, in the presence of the protein synthesis inhibitor cycloheximide. Actinomycin D blocked induction, suggesting involvement of gene transcription. The half-life of IL-1ra transcripts was prolonged by IL-13 from 1.3 hours to 4.5 hours in monocytes and to 12 hours in PMN. By reverse transcriptase-polymerase chain reaction, IL-13 was found to augment the transcripts coding for the soluble form of IL-1ra, but also to induce the expression of the intracellular (keratinocyte) form of IL-1ra, the latter being extremely low or undetectable in myelomonocytic cells. IL-13 induced production of IL-1ra in myelomonocytic cells, augmenting both cell-associated and released protein. Induction of IL-1ra by IL-13 may represent a further mechanism by which this molecule can counteract the potent proinflammatory properties of IL-1.

Cells, Cultured↗

PubMed1994

Monocyte chemotactic protein 3 is a most effective basophil- and eosinophil-activating chemokine.

CC chemokines constitute a novel class of cytokines that attract and activate monocytes and lymphocytes, as well as basophil and eosinophil leukocytes, with distinct target cell profiles, and are believed to be involved in the regulation of different types of inflammation. The action of the recently identified monocyte chemotactic protein 3 (MCP-3) on human basophil and eosinophil function was studied and compared with that of other CC chemokines. In basophils, MCP-3, MCP-1, RANTES, and macrophage inflammatory protein (MIP)-1 alpha all induced cytosolic-free calcium concentration ([Ca2+]i) changes and, with different efficacies, chemotaxis (RANTES = MCP-3 >> MCP-1 > MIP-1 alpha), histamine release (MCP-1 = MCP-3 >> RANTES > MIP-1 alpha), and leukotriene C4 formation, after IL-3 pretreatment (MCP-1 = MCP-3 >> RANTES > MIP-1 alpha). Thus, MCP-3 was as effective as MCP-1 as an inducer of mediator release, and as effective as RANTES as a stimulus of basophil migration. In contrast to MCP-1, MCP-3 was also a stimulus for eosinophils, and induced [Ca2+]i changes and chemotaxis as effectively as RANTES, which is the most potent chemotactic cytokine for these cells. Desensitization of the transient changes in [Ca2+]i was used to assess receptor usage. In basophils, stimulation with MCP-3 prevented responsiveness to MCP-1 and RANTES, but not to MIP-1 alpha. No single CC chemokine (except for MCP-3 itself) affected the response to MCP-3, however, which was prevented only when the cells were prestimulated with both MCP-1 and RANTES. In eosinophils, by contrast, cross-desensitization between RANTES and MCP-3 was obtained. RANTES and to a lesser extent MCP-3 also desensitized eosinophils toward MIP-1 alpha. The desensitization data suggest the existence of three chemokine receptors: (a) a MCP-1 receptor expressed on basophils but not eosinophils that is activated by MCP-1 and MCP-3; (b) a RANTES receptor in basophils and eosinophils that is activated by RANTES and MCP-3; and (c) a MIP-1 alpha receptor that is activated by MIP-1 alpha, RANTES and, more weakly, by MCP-3. This study shows that MCP-3 combines the properties of RANTES, a powerful chemoattractant, and MCP-1, a highly effective stimulus of mediator release, and thus has a particularly broad range of activities toward both human basophil and eosinophil leukocytes.

Basophils↗

PubMed1994

Interleukin 13 is a B cell stimulating factor.

The recently cloned human interleukin 13 (IL-13) is a novel cytokine expressed in activated T cells that has been shown to inhibit inflammatory cytokine production by lipopolysaccharide-activated monocytes. The protein encoded by the IL-13 cDNA is the human homologue of a mouse Th2-product called P600. Here, we show that IL-13 acts at different stages of the B cell maturation pathway: (a) it enhances the expression of CD23/Fc epsilon RII and class II MHC antigens on resting B cells; (b) it stimulates B cell proliferation in combination with anti-Ig and anti-CD40 antibodies; and (c) it induces IgE synthesis. Thus, the spectrum of the biological activities of IL-13 on B cells largely overlaps that previously ascribed to IL-4. The present observations suggest that IL-13 may be an important factor, in addition to IL-4, in the development of allergic diseases.

B-Lymphocytes↗

PubMed1994

IL-4 and IL-13 have overlapping but distinct effects on HIV production in monocytes.

In HIV-1-infected monocytes and monocytoid cell lines, viral expression can be observed as high-level production, restricted (chronic low-level) expression, and latency (no viral expression). Interleukin-13 (IL-13) and IL-4, which have remarkedly similar deactivating effects on inflammatory monocyte functions, were studied for their regulation of HIV expression in monocytes. Pretreatment of peripheral monocytes for 48-72 h with IL-13 markedly decreased acute HIV infection, whereas IL-4 increased it. Similar effects were seen when the U1 and R-THP-1 monocytoid cell lines with restricted HIV expression were treated with these cytokines. However, when these continuously producing cell lines were chronically treated with cytokines, IL-13 increased HIV production. Neither IL-4 nor IL-13 stimulated HIV expression in latently infected cells. In chronically infected cells, several cytokines reduced viral mRNA. Both IL-4 and IL-13 increased monocyte aggregate formation, but only IL-4 ultimately stimulated cytolysis of HIV-infected monocytes as well as increased apoptosis of U1. In the presence of tumor necrosis factor alpha or IL-6, which upregulate HIV expression, IL-13 could no longer suppress HIV expression. These results indicate that IL-4 and IL-13, although closely related in modulating monocyte function, can have divergent effects on HIV expression in monocytes. Collectively, these data suggest that there exists a complex cytokine tissue environment with positive regulators of HIV expression able to override negative regulators.

Cells, Cultured↗

PubMed1993

IL-4 and IL-13 exhibit comparable abilities to reduce pyrogen-induced expression of procoagulant activity in endothelial cells and monocytes.

Endotoxin (LPS), interleukin-1 beta (IL-1) and tumor necrosis factor-alpha (TNF) increased the expression of tissue factor, a membrane-anchored glycoprotein that initiates blood coagulation on the surface of cultured bovine aortic endothelial cells (ABAE) and human monocytes. These compounds simultaneously reduced the amount of thrombomodulin on the endothelial cell surface, further contributing to the procoagulant activity of the endothelium or monocytes. On endothelial cells and monocytes, interleukin-4 (IL-4) and interleukin-13 (IL-13), a newly described lymphokine, both strongly inhibited LPS-induced tissue factor expression, a similar activity also being obtained with regard to the pyrogenic effects of IL-1 or TNF. When measured in parallel, IL-4 and IL-13 counteracted thrombomodulin down-regulation induced by LPS, IL-1 or TNF in endothelial cells. These results therefore show that both IL-4 and IL-13 protect the endothelial and the monocyte surface against inflammatory mediator-induced procoagulant changes.

Animals↗

PubMed1993

Interleukin 13 inhibits human immunodeficiency virus type 1 production in primary blood-derived human macrophages in vitro.

The mechanisms by which cellular immunity maintains the asymptomatic state after human immunodeficiency virus type 1 (HIV-1) infection are poorly understood. CD4+ T lymphocytes play a complex role in regulating anti-HIV effector pathways, including activation of macrophages, which are themselves implicated in clinical latency and pathogenesis of symptomatic acquired immune deficiency syndrome. We have found that a newly identified T helper type 2 lymphokine, interleukin 13 (IL-13), inhibits HIV-1ADA and Ba-L replication in primary tissue culture-derived macrophages but not in peripheral blood lymphocytes. Viral production in cells was measured by viral protein (p24) and reverse transcriptase levels, while entry was assessed by proviral DNA analysis at timed intervals after infection. Inhibition by IL-13 was dose and time dependent and not mediated through altered viral entry, reverse transcription, or viral release. IL-13 is therefore a candidate cytokine for the suppression of HIV infection within monocytes and macrophages in vivo.

Base Sequence↗

PubMed1993

Interleukin-13 is a new human lymphokine regulating inflammatory and immune responses.

The discovery of new cytokines normally relies on a prior knowledge of at least one of their biological effects, which is used as a criterion either for the purification of the protein or for the isolation of the complementary DNA by expression cloning. However, the redundancy of cytokine activities complicates the discovery of novel cytokines in this way, and the pleiotropic nature of many cytokines means that the principal activities of a new cytokine may bear little relation to that used for its isolation. We have adopted an alternative approach which relies on differential screening of an organized subtracted cDNA library from activated peripheral blood mononuclear cells, using the inducibility of lymphokine messenger RNAs by anti-CD28 as a primary screening criterion. The ligation of the CD28 antigen on the T lymphocyte by a surface antigen, B7/BB-1, expressed on activated B lymphocytes and monocytes is a key step in the activation of T lymphocytes and the accumulation of lymphokine mRNAs. Here we report the discovery by molecular cloning of a new interleukin (interleukin-13 or IL-13) expressed in activated human T lymphocytes. Recombinant IL-13 protein inhibits inflammatory cytokine production induced by lipopolysaccharide in human peripheral blood monocytes. Moreover, it synergizes with IL-2 in regulating interferon-gamma synthesis in large granular lymphocytes. Recent mapping of the IL-13 gene shows that it is closely linked to the IL-4 gene on chromosome 5q 23-31 (ref. 4). Interleukin-13 may be critical in regulating inflammatory and immune responses.

Amino Acid Sequence↗