Cloning and sequencing of the cDNA for human monocyte chemotactic and activating factor (MCAF)

Monocyte chemoattractant protein-1 in human atheromatous plaques

Monocytes appear to be central to atherogenesis both as the progenitors of foam cells and as a potential source of growth factors mediating intimal hyperplasia, but the chemical messages which stimulate the influx of monocytes into human atheroma remain unknown. Monocyte chemoattractant protein-1 (MCP-1) is a recently described molecule with powerful monocyte chemotactic activity expressed by monocytes, vascular endothelial cells, and smooth muscle cells in culture. To begin to address the role of MCP-1 in vivo, we examined 10 normal arteries and 14 diseased human arteries for MCP-1 expression by in situ hybridization. MCP-1 mRNA was detected in 16% of 10,768 cells counted in human carotid endarterectomy specimens with highest expression seen in organizing thrombi (33%) and in macrophage rich areas bordering the necrotic lipid core (24%) as compared to the fibrous cap (8%) and the necrotic lipid core itself (5%). Based on immunohistochemical staining of serial sections and on cell morphology, MCP-1 mRNA appeared to be expressed by vascular smooth muscle cells (VSMC), mesenchymal appearing intimal cells (MICs), and macrophages. By contrast, few cells expressing MCP-1 mRNA were found in normal arteries (less than 0.1%). These data suggest a potential role for MCP-1 in mediating monocytic infiltration of the artery wall.

Macrophage infiltration and growth of sarcoma clones expressing different amounts of monocyte chemotactic protein/JE

Tumor-derived chemotactic factors (TDCF) have been identified and thought to play a role in the regulation of macrophage infiltration in neoplastic tissues. The present study was designed to assess the in vivo relevance of the TDCF molecularly identified as monocyte chemotactic protein/JE, by investigating murine sarcoma clones expressing different levels of MCP/JE. The 1D3 clone derived from the B77 RSV-induced sarcoma expressed appreciable levels of MCP/JE mRNA and, concomitantly, chemotactic activity for mononuclear phagocytes. In contrast, the 5B11 clone from the same tumor had undetectable levels of MCP/JE transcripts and little or no chemotactic activity. The chemotactic activity of 1D3 cells was blocked by an appropriate specific antiserum. The in vitro growth rate of the 2 sarcoma lines was identical. Upon in vivo transplantation, the 1D3 clone showed a substantially higher level of tumor-associated macrophages (28.9%; range 21%-34%) than the 5B11 clone (16.6%; range 13%-20%). 5B11-induced tumors appeared earlier and grew faster than those induced by 1D3. The difference in growth rate and in macrophage infiltration between 1D3 and 5B11 clones was also evident upon transplantation into nude mice. These results are consistent with the hypothesis that TDCF, identified as MCP/JE, is one important determinant of macrophage infiltration in tumors.

Expression and secretion of leukocyte chemotactic cytokines by normal human melanocytes and melanoma cells

The capacity of human melanocytes and melanoma cells to produce IL-8 and monocyte chemotactic and activating factor (MCAF) was investigated. Melanocytes expressed mRNA for IL-8 and MCAF, when stimulated with either IL-1 alpha or TNF alpha, but not when stimulated with IL-6, IFN gamma, or LPS alone. IL-8 and MCAF could be induced in a dose-dependent fashion with doses as low as 0.1 ng/ml TNF alpha and 0.5 ng/ml IL-1 alpha. IL-8 and MCAF mRNA were rapidly expressed and peaked between 2 and 4 h for IL-8 and between 4 and 8 h for MCAF. This correlated well with the accumulation of IL-8 antigen as measured by a radioimmunoassay. Supernatants from melanocyte cultures stimulated with either IL-1 alpha or TNF alpha and separated on a heparin-Sepharose column became positive for neutrophil and monocyte chemotactic activity in a dose- and time-dependent fashion. When IFN gamma was added to melanocyte cultures stimulated with suboptimal doses of TNF alpha there was a synergistic increase in secreted IL-8 protein and monocyte chemotactic activity. These data provide further evidence for the possible role of melanocytes in the initiation of an inflammatory reaction. Three different malignant melanoma cell lines stimulated with either TNF alpha or IL-1 alpha expressed IL-8 mRNA, but not mRNA for MCAF. The IL-8 mRNA signal corresponded well with the amount of secreted IL-8 protein. These data suggest that IL-8 and MCAF may play a role in growth regulation and spreading of melanomas.

Expression of monocyte chemotactic protein and interleukin-8 by cytokine-activated human vascular smooth muscle cells

The present study was designed to investigate the capacity of human vascular smooth muscle cells (SMCs) to produce a cytokine chemotactic for monocytes (monocyte chemotactic protein [MCP]) and by way of comparison, a related polypeptide activator of neutrophils (known as interleukin-8 [IL-8] or neutrophil activating protein-1 [NAP-1]. On exposure to IL-1, SMCs released high levels of chemotactic activity for monocytes, which could be removed by absorption with anti-MCP antibodies. MCP production by activated SMCs was comparable to that of IL-1-stimulated umbilical vein endothelial cells. Activated SMCs released appreciable levels of IL-8, as determined by a specific enzyme-linked immunosorbent assay, but little chemotactic activity for neutrophils. IL-1-treated SMCs expressed high levels of both MCP and IL-8 mRNA transcripts, as assessed by Northern blot analysis. Tumor necrosis factor and bacterial lipopolysaccharide but not IL-6 also induced MCP and IL-8 gene expression in SMCs. Nuclear runoff analysis revealed that IL-1 augmented transcription of the MCP and IL-8 genes. The capacity of SMCs to produce a cytokine (MCP) that recruits and activates circulating mononuclear phagocytes may be of considerable importance in the pathogenesis of vascular diseases (e.g., vasculitis and atherosclerosis) that are characterized by monocyte infiltration of the vessel wall.

Suppression of tumor formation in vivo by expression of the JE gene in malignant cells

The early growth response gene JE encodes a monocyte chemoattractant, MCP-1. The JE/MCP-1 protein attracts and stimulates human monocytes and induces monocyte-mediated inhibition of tumor cell growth in vitro. Expression of human or murine JE/MCP-1 in Chinese hamster ovary (CHO) cells completely suppressed their ability to form tumors in nude mice. Coinjection of JE/MCP-1-expressing cells with nonexpressing CHO cells or with HeLa cells also prevented tumor formation. Since JE/MCP-1 expression had no discernible effect on the tranformed phenotype of these cells in vitro, the suppressive effect depends on host animal factors. These factors are likely to be components of the inflammatory response, because JE/MCP-1-expressing cells elicited a predominantly monocytic infiltrate at the site of injection. Our results suggest that JE/MCP-1 protein may be useful in cancer therapy.

Chemotactic cytokine (IL-8 and MCP-1) gene expression by human whole blood

The salient features of systemic or local inflammation are the myriad of cellular and humoral interactions that result in elicitation of inflammatory leukocytes. In this study using specialized connective tissue, intact whole blood, we demonstrate the gene expression of two novel chemotactic factors. The buffy-coat cellular expression of neutrophil chemotactic/activating factor/interleukin 8 (IL-8) and monocyte chemotactic/activating protein (MCP-1) mRNA were time and dose-dependent in response to either lipopolysaccharide or zymosan stimulation. This system with the complexity of tissue provides a unique model for the determination of chemotactic cytokine gene expression.

Assignment of the human small inducible cytokine A2 gene, SCYA2 (encoding JE or MCP-1), to 17q11.2-12: evolutionary relatedness of cytokines clustered at the same locus

The JE gene, cloned from platelet-derived growth factor (PDGF)-treated mouse 3T3 cells, was the first PDGF-inducible gene to be described. Its human homolog (gene name "small inducible cytokine A2" [SCYA2]) encodes the monocyte specific chemotactic factor MCP-1 (or MCAF) which is structurally related to a recently described family of cytokines. By a combination of in situ hybridization and study of somatic cell hybrids, we have assigned the human SCYA2 gene to 17q11.2-12, the locus to which other members of this family have been mapped. We have also reconstructed a phylogenetic tree relating the members of this family to each other and to their murine homologs which suggests that these genes arose by duplication and divergence prior to the murine/human divergence. Four of the five members of this subfamily have now been assigned to the same locus (and the fifth to chromosome 17), while several of the members of a related gene family have been assigned to 4q. We propose that the two subfamilies be designated the 17q and 4q subfamilies.

Suppression of tumor formation in vivo by expression of the JE gene in malignant cells

The early growth response gene JE encodes a monocyte chemoattractant, MCP-1. The JE/MCP-1 protein attracts and stimulates human monocytes and induces monocyte-mediated inhibition of tumor cell growth in vitro. Expression of human or murine JE/MCP-1 in Chinese hamster ovary (CHO) cells completely suppressed their ability to form tumors in nude mice. Coinjection of JE/MCP-1-expressing cells with nonexpressing CHO cells or with HeLa cells also prevented tumor formation. Since JE/MCP-1 expression had no discernible effect on the tranformed phenotype of these cells in vitro, the suppressive effect depends on host animal factors. These factors are likely to be components of the inflammatory response, because JE/MCP-1-expressing cells elicited a predominantly monocytic infiltrate at the site of injection. Our results suggest that JE/MCP-1 protein may be useful in cancer therapy.

Monocyte chemotactic proteins from human tumor cells

The production of the monocyte chemoattractant MCP-1 suggests a common mechanism for the recruitment of monocytes/macrophages and provides an explanation for monocyte/macrophage infiltration frequently observed in solid tumors. The regulated production of MCP-1 by non-transformed cells further substantiates the suggestion that MCP-1 is an important inflammatory mediator and is involved in the recruitment of monocytes in a number of pathologic or physiologic conditions.

Interleukin-1 induced gene expression of neutrophil activating protein (interleukin-8) and monocyte chemotactic peptide in human synovial cells

We report here that human synovial cells stimulated by interleukin-1 alpha and interleukin-1 beta express mRNA for both IL-8 (neutrophil chemotactic peptide) and monocyte chemotactic protein. IL-1 stimulated synovial cells from both osteoarthritis and rheumatoid arthritis patients exhibited similar mRNA expression of interleukin-8 and monocyte chemotactic protein. A capacity to produce factors selectively chemotactic for neutrophils, lymphocytes and monocytes provides a mechanism whereby synovial cells can facilitate inflammatory arthritis.

Crystal structure of interleukin 8: symbiosis of NMR and crystallography

The crystal structure of a host defense system chemotactic factor, interleukin 8, has been solved by molecular replacement using as a model the solution structure derived from nuclear magnetic resonance experiments. The structure was refined with 2 A x-ray data to an R factor of 0.187 (0.217 at 1.6 A). A comparison indicates some potential differences between the structure in solution and in the crystalline state. Our analysis also predicts that residues 4 through 9 on the amino terminus and the beta-bend, which includes His-33, may be important for receptor binding.

Stimulus specific induction of monocyte chemotactic protein-1 (MCP-1) gene expression

The recruitment of monocytes from the peripheral vasculature to an area of chronic inflammation is a complex phenomenon. This complicated process is likely mediated to a large extent by chemotactic cytokines that are expressed via a cytokine cascade. A number of chronic diseases that are difficult to manage are characterized by a significant infiltrate of monocytes, including sarcoidosis, Wegener's granulomatosis, and tuberculosis. New scientific insight into the mechanisms that lead to early activation events, such as monocyte elicitation, may aid in both better understanding these diverse processes and designing more effective therapies.

Regulation of human interleukin 8 gene expression and binding of several other members of the intercrine family to receptors for interleukin-8

IL-8 is produced by a wide variety of cells in response to polyclonal mitogens and cytokines. Northern blotting analysis revealed that IL-1, TNF and PMA could induce rapid expression of IL-8 mRNA in the absence of new protein synthesis. Nuclear run-off assays using different cell types demonstrated that IL-8 mRNA expression could at least be partly due to the activation of transcription. Cloning and determination of the entire sequence of IL-8 genomic DNA enabled us to explore the functional significance of the 5'-flanking enhancer region of the IL-8 gene by employing CAT assays. The results indicated that the region spanning from -94 to -71 bp is minimally sufficient for conferring responsiveness to IL-1, TNF and PMA. Further analysis using point-mutations revealed that this region consisted of two distinct cis-elements; one being the potential binding site for NFkB-like and the other for a C/EBP-like factor. These results suggested that all three stimuli, IL-1/TNF/PMA, modulate the identical combination of nuclear factors possibly by phosphorylation. We previously reported that these three stimuli activated the same serine protein kinase which phosphorylates identical 65 kDa and 74 kDa cytosol proteins in human PBMC. This IL-1/TNF/PMA-activated protein kinase is distinct from protein kinase A, protein kinase C or casein kinase in substrate specificity; in Ca and phospholipid dependency; in cyclic nucleotide dependency; and sensitivity to protein kinase inhibitors. Taken collectively, IL-1/TNF/PMA may activate a common serine protein kinase and this protein kinase may in turn directly or indirectly modulate several nuclear factors.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemotactic cytokine gene expression and production induced in human monocytes by membrane proteoglycans from Klebsiella pneumoniae

The present study was designed to investigate the effect of membrane proteoglycans (MPG) from Klebsiella pneumoniae on production of the chemotactic cytokine, IL-8, and monocyte chemotactic protein (MCP) by human peripheral blood monocytes. Exposure of human peripheral blood monocytes to MPG in vitro induced high levels of mRNA transcripts for IL-8 and MCP, as assessed by Northern blot analysis. Cytokine gene expression was associated with the production of chemotactic activity in the supernatants. The levels of IL-8 and MCP expression induced by MPG were comparable with those elicited by LPS. Induction of chemotactic cytokines in mononuclear phagocytes may play a role in the immunomodulatory activity of MPG.

PDGF and the small inducible gene (SIG) family: roles in the inflammatory response

A growing body of evidence suggests that cells responding to an initial growth, inflammatory or immune signal can respond by inducing the transcription of selective members of the SIG family. This family of related inducible cytokines are involved in the amplification, propagation and coordination of intercellular communication among cell types involved in the immune and inflammatory responses. The principal anti-inflammatory action of glucocorticoids may involve the transcriptional and translational inhibition of cytokines such as JE and other members of the SIG family to effectively disrupt the normal lines of intercellular communication which normally coordinates the immune and inflammatory response. The identification of new members of the family and the discovery of the functions of the known members will lead to a clearer understanding of the complicated processes which lead to normal and pathological immune and inflammatory responses.

Human neutrophils exhibit disparate chemotactic factor gene expression

The evolution of acute inflammation from initiation through resolution is associated with the changing character of the infiltrating leukocytes. Recruitment of these leukocytes is dependent upon the generation of chemotactic factors that have either global or specific activity for a particular leukocyte. In this manuscript we present data demonstrating that human neutrophils can express mRNA for neutrophil chemotactic factor/interleukin 8 (IL-8), but fail to express mRNA for monocyte chemotactic protein (MCP-1). The expression of IL-8 was observed upon adherence or in response to stimulation with lipopolysaccharide. Maximal IL-8 antigenic production was noted at 24 hrs. These studies demonstrate a disparate expression of chemotactic cytokines by neutrophils.

Antitumor effect of PSK at a distant site: inductions of interleukin-8-like factor and macrophage chemotactic factor in murine tumor

The antitumor effect of PSK, a Coriolus preparation, at a distant site was analyzed with the use of a double grafted tumor system in which male BALB/c mice received simultaneous intradermal inoculations of Meth-A tumor in the right (10(6) cells) and the left (2 x 10(5) cells) flanks and were then injected with PSK in the right tumor on the third day thereafter. The antitumor effect of intratumoral administration of PSK in the right tumor on days 3, 4 and 5 was compared with the effect of surgical resection of the right tumor on day 5. Three out of 8 mice given PSK intratumorally became tumor-free whereas no mouse tumor-free in the left flank was found among the surgically resected mice. As regards sinecomitant immunity, tumor inoculation into the right flank followed by intra-tumoral administration of PSK on days 3 and 5 and surgical excision of the primary tumor on day 6 resulted in complete rejection of a tumor challenge in the left flank on day 21. The combination of presurgical intratumoral injections of PSK (more than 2 times) and postoperative oral administration of PSK appeared to be most effective in eradicating secondary tumors. Isolated TILs (tumor-infiltrating lymphocytes), obtained from the right tumor (treated with PSK) and the left tumor on day 10 in the double grafted tumor system were cultured in RPMI1640 with 10% fetal calf serum for 24 h. The culture supernatants were harvested and tested for the presence of chemotactic activity for neutrophils or macrophages. Significant neutrophil chemotactic factor (NCF) and macrophage chemotactic factor (MCF) activities were detected in the culture media from PSK-treated TILs that had been cultured for 24 h. Neither significant neutrophil nor macrophage chemotactic activity was detected in the media from untreated TILs. NCF and MCF activities were also detected in the culture supernatant from PSK-treated tumor tissue on day 6. PSK-induced NCF in the murine tumor was neutralized by treatment with anti-human IL-8 IgG, and might be murine IL-8-like factor. Therefore, neutrophil and macrophage infiltrations of tumors following intratumoral injections of PSK are probably mediated by inductions of IL-8-like factor and MCF.

Properties of monocyte chemotactic and activating factor (MCAF) purified from a human fibrosarcoma cell line

A monocyte chemotactic and activating factor (MCAF) has been purified from TNF-stimulated 8387 human fibrosarcoma cell line-conditioned media. The purified MCAF showed microheterogeneity yielding two bands on SDS-PAGE analysis. Fibrosarcoma-derived MCAF specifically competed with THP-1 (a human monocytic cell line)-derived 125I-labeled MCAF in binding to human PBMC, whereas a similar basic heparin-binding leukocyte chemoattractant, IL-8, did not. The purified MCAF stimulated superoxide anion and N-acetyl beta-D glucosaminidase-releasing activity in human monocytes, as well as monocyte cytostatic augmenting activity against tumor cells and chemotactic activity for monocytes. When injected subcutaneously into Lewis rat ears, the purified human MCAF also induced considerable in vivo local monocyte infiltration beginning at 3 h and becoming maximal at 18 h. In conclusion, the data presented in this paper indicate that MCAF is a potent activator of monocytes as well as a monocyte recruitment factor that acts through receptors that are specific for this novel molecule. This novel cytokine might have an important role in tumor growth control due to its ability to attract and activate monocytes.

Isolation and characterization of eight tumor necrosis factor-induced gene sequences from human fibroblasts

A lambda cDNA library was prepared from polyadenylated RNA isolated from quiescent human diploid FS-4 fibroblasts stimulated with tumor necrosis factor for 3 h. Differential screening was used to isolate cDNA sequences that are stimulated by tumor necrosis factor. Eight distinct tumor necrosis factor-stimulated gene sequences (designated TSG-1, -6, -8, -12, -14, -21, -27, and -37) were partially sequenced and compared with known sequences from GenBank. TSG-1 was identical to the gene for interleukin-8. TSG-8 corresponded to the gene for monocyte chemotactic and activating factor. TSG-21 and -27 were identical to the genes for collagenase and stromelysin, respectively. The other four sequences showed no homologies with known genes. Patterns of induction of mRNAs corresponding to the eight cloned cDNAs by various cytokines, growth factors, and activators of second messenger pathways were analyzed in FS-4 cells.

Isolation and characterization of eight tumor necrosis factor-induced gene sequences from human fibroblasts

A lambda cDNA library was prepared from polyadenylated RNA isolated from quiescent human diploid FS-4 fibroblasts stimulated with tumor necrosis factor for 3 h. Differential screening was used to isolate cDNA sequences that are stimulated by tumor necrosis factor. Eight distinct tumor necrosis factor-stimulated gene sequences (designated TSG-1, -6, -8, -12, -14, -21, -27, and -37) were partially sequenced and compared with known sequences from GenBank. TSG-1 was identical to the gene for interleukin-8. TSG-8 corresponded to the gene for monocyte chemotactic and activating factor. TSG-21 and -27 were identical to the genes for collagenase and stromelysin, respectively. The other four sequences showed no homologies with known genes. Patterns of induction of mRNAs corresponding to the eight cloned cDNAs by various cytokines, growth factors, and activators of second messenger pathways were analyzed in FS-4 cells.

Clustering of cytokine genes on mouse chromosome 11

The presence of positionally conserved amino acid residues suggests that the mouse proteins TCA3, P500, MIP1-alpha, MIP1-beta, and JE are members of a single gene family. These proteins are activation specific and can be expressed by both myeloid and lymphoid cells. MIP1-alpha/MIP1-beta and MCAF (the putative human homologue of JE) act as chemotactic and activating agents for neutrophils and macrophages, respectively. The functions of TCA3 and P500 are unknown. We have used interspecies somatic cell hybrids and recombinant inbred mouse strains to show that the genes encoding TCA3, MIP1-alpha, MIP1-beta, and JE (provisionally termed Tca3, Mip-1a, Mip-1b, and Sigje, respectively) map as a cluster on the distal portion of mouse chromosome 11 near the Hox-2 gene complex. DNA sequence analysis indicates that the P500 and TCA3 proteins are encoded by alternative splicing products of one genomic gene. Additionally, the genes encoding TCA3 and JE are found to be strikingly similar with respect to the positions of intron-exon boundaries. Together, these data support the model that the cytokines TCA3, P500, MIP1-alpha, MIP1-beta, and JE are encoded by a single cluster of related genes. The gene encoding IL-5 (Il-5), which acts as a T cell-replacing factor, a B cell growth factor, and an eosinophil differentiation factor, is also mapped to mouse chromosome 11.Il-5 maps approximately 25 cM proximal to the Tca-3 gene and appears tightly linked to a previously described gene cluster that includes Il-3, Il-4, and Csfgm. We discuss the potential relevance of the two cytokine gene clusters described here with particular attention to specific human hematologic malignancies associated with chromosomal aberrations at corresponding locations on human chromosomes 5 and 17.

Identification of the monocyte chemotactic protein from human osteosarcoma cells and monocytes: detection of a novel N-terminally processed form

The chemotactic activity for monocytes in culture supernatants from double-stranded RNA-stimulated human MG-63 osteosarcoma cells and from LPS-stimulated human monocytes was purified to homogeneity and characterized by amino acid sequence analysis. The chemotactic protein derived from the fibroblastoid osteosarcoma cells had a blocked N-terminus but sequencing of tryptic fragments showed that it was identical with a recently identified monocyte chemoattractant designated MCP-1 or MCAF isolated from glioma or myelomonocytic cells, respectively. Preparations of monocyte -derived chemotactic activity appeared to contain not only the blocked protein, but also a novel N-terminally processed form of this molecule, lacking 5 amino acid residues.

Human monocyte chemoattractant protein-1 (MCP-1)

During the past three years great advances have been made in the chemistry and biology of chemoattractants for human leukocytes. Two chemoattractant cytokines have been isolated, sequenced and cloned, each with distinctive leukocyte attractant specificity. Monocyte chemoattractant protein 1 (MCP-1), the subject of this review by Edward Leonard and Teizo Yoshimura, is secreted by PHA-stimulated mononuclear cells and can be identified by northern blotting in response to LPS or PHA. It attracts monocytes but not neutrophils. In contrast, neutrophil attractant/activation protein (NAP-1) (also known as interleukin 8 (IL-8)) attracts and activates human neutrophils but it is not a chemoattractant for human monocytes. Based on amino acid sequence analysis, each of these attractants has been assigned to one of two distinct families of cytokines that are thought to participate in host defense and inflammatory responses.

The human homolog of the JE gene encodes a monocyte secretory protein

The mouse fibroblast gene, JE, was one of the first platelet-derived growth factor-inducible genes to be described as such. The protein encoded by JE (mJE) is the prototype of a large family of secreted, cytokinelike glycoproteins, all of whose members are induced by a mitogenic or activation signal in monocytes macrophages, and T lymphocytes; JE is the only member to have been identified in fibroblasts. We report the identification of a human homolog for murine JE, cloned from human fibroblasts. The protein predicted by the coding sequence of human JE (hJE) is 55 amino acids shorter than mJE, and its sequence is identical to that of a recently purified monocyte chemoattractant. When expressed in COS cells, the human JE cDNA directed the secretion of N-glycosylated proteins of Mr 16,000 to 18,000 as well as proteins of Mr 15,500, 15,000, and 13,000. Antibodies raised against mJE recognized these hJE species, all of which were secreted by human fibroblasts. hJE expression was stimulated in HL60 cells during phorbol myristate acetate-induced monocytoid differentiation. However, resting human monocytes constitutively secreted hJE; treatment with gamma interferon did not enhance hJE expression in monocytes, and treatment with phorbol myristate acetate or lipopolysaccharide inhibited its expression. Thus, human JE encodes yet another member of the large family of JE-related cytokinelike proteins, in this case a novel human monocyte and fibroblast secretory protein.

Disparate gene expression of chemotactic cytokines by human mononuclear phagocytes

Chemotactic cytokines are becoming increasingly recognized as important participants in the coordinate recruitment of specific inflammatory cells. In this manuscript we present data demonstrating that LPS challenged human mononuclear phagocytic cells can express mRNA for neutrophil chemotactic factor/interleukin-8 (NCF/IL-8), but do not express mRNA for monocyte chemotactic protein (MCP). The expression of NCF/IL-8 mRNA was time and dose dependent. This identical stimulus response was also found in peripheral blood neutrophils. These studies demonstrate a disparate production of chemotactic cytokines by macrophages and exemplify the dynamic nature of the chemotactic response.

Cellular and molecular aspects of granulomatous inflammation

Recent advances in cellular and molecular biology have provided important new avenues to assess mechanisms of granuloma formation/regulation. For example, current studies have identified various cytokines that can exert a powerful influence on both immune and non-immune cells and dictate inflammatory processes. Some of these cytokines are potentially active during the initiation and maintenance of chronic inflammation, including tumor necrosis factor, interleukin 1, and a novel class of chemotactic cytokines. This latter group of mediators belongs to a super-gene family of immune signals that play a key role in the selective recruitment of inflammatory cells to an area of inflammation. The coordinated synthesis of these cytokines is likely important to the development of the granulomatous response. The participation of molecular signals produced by non-inflammatory cells, fibroblasts, and epithelial cells, also warrants special consideration. These "bystander" cells appear to possess effector cell functions and likely serve an important role in inducing pulmonary granulomatous inflammation. Thus, a clear understanding of the cells and molecular signals involved in the initiation and maintenance of chronic pulmonary inflammation will be necessary to assess lesion development and design more selective/effective therapies.

Identification by sequence analysis of chemotactic factors for monocytes produced by normal and transformed cells stimulated with virus, double-stranded RNA or cytokine

A monocyte chemotactic activity was found to be released by various types of cultured human cells after appropriate stimulation: normal diploid fibroblasts, peripheral blood mononuclear cells or monocytes isolated therefrom, and a number of tumor cell lines, including osteosarcoma (MG-63) and hepatoma (Malavu) but not melanoma (Bowes) cells. Cultures of diploid human fibroblasts and these tumor cells stimulated with interleukin (IL) 1 or double-stranded RNA [poly(rI).poly(rC)], or infected with viruses (measles or rubella viruses) were found to produce chemotactic activity for both monocytes and granulocytes. Media collected from fibroblasts treated with E. coli or IL 6 did not contain such activity. Granulocyte and monocyte chemotactic activities were serologically distinct, and could be separated by successive chromatographical procedures. While the granulocyte chemotactic activity of both fibroblasts and MG-63 cells had previously been identified as granulocyte chemotactic protein/IL 8, the monocyte chemotactic activity from MG-63 cells was identified by amino acid sequence analysis as a different protein recently described to be released by human glioma and myelomonocytic cell lines. In view of the similarity in their chromatographical behavior, monocyte chemotactic activities from fibroblasts, MG-63 cells and fresh monocytes can probably be assigned to identical molecules. Cultures of unfractionated peripheral blood cells, however, were found to release an additional monocyte chemotactic protein, identifiable by amino acid sequence analysis as platelet factor 4.

The human homolog of the JE gene encodes a monocyte secretory protein

The mouse fibroblast gene, JE, was one of the first platelet-derived growth factor-inducible genes to be described as such. The protein encoded by JE (mJE) is the prototype of a large family of secreted, cytokinelike glycoproteins, all of whose members are induced by a mitogenic or activation signal in monocytes macrophages, and T lymphocytes; JE is the only member to have been identified in fibroblasts. We report the identification of a human homolog for murine JE, cloned from human fibroblasts. The protein predicted by the coding sequence of human JE (hJE) is 55 amino acids shorter than mJE, and its sequence is identical to that of a recently purified monocyte chemoattractant. When expressed in COS cells, the human JE cDNA directed the secretion of N-glycosylated proteins of Mr 16,000 to 18,000 as well as proteins of Mr 15,500, 15,000, and 13,000. Antibodies raised against mJE recognized these hJE species, all of which were secreted by human fibroblasts. hJE expression was stimulated in HL60 cells during phorbol myristate acetate-induced monocytoid differentiation. However, resting human monocytes constitutively secreted hJE; treatment with gamma interferon did not enhance hJE expression in monocytes, and treatment with phorbol myristate acetate or lipopolysaccharide inhibited its expression. Thus, human JE encodes yet another member of the large family of JE-related cytokinelike proteins, in this case a novel human monocyte and fibroblast secretory protein.

Monocyte chemotactic protein gene expression by cytokine-treated human fibroblasts and endothelial cells

A number of cytokines are active during the evolution of an inflammatory response, including tumor necrosis factor-alpha, interleukin-1, and novel chemotactic cytokines. This latter group of mediators belong to supergene families of inflammatory signals that play a key role in the selective recruitment of immune cells. In this presentation, we present data demonstrating, for the first time, endothelial cell expression of monocyte chemotactic protein (MCP) mRNA induced by LPS, interleukin-1 or tumor necrosis factor. Human fibroblasts were also found to express monocyte chemotactic factor mRNA in response to interleukin-1 or tumor necrosis factor, but LPS was not effective. In addition, neither primary cultures expressed MCP in response to interleukin-6. These studies demonstrate that non-immune "bystander" cells can play an active role in the recruitment of inflammatory cells via the production of novel chemotactic cytokines.

Interleukin 3-dependent and -independent mast cells stimulated with IgE and antigen express multiple cytokines

In response to IgE and specific multivalent antigen, mast cell lines (both growth factor-dependent and -independent) induce the transcription and/or secretion of a number of cytokines having a wide spectrum of activities. We have identified IL-1, IL-3, IL-5, IL-6, IFN-gamma, GM-CSF, JE, MIP1 alpha, MIP1 beta, and TCA3 RNA in at least two of four mast cell clones. The production of these products (except JE) is activation-associated and can be induced by IgE plus antigen. In selected instances cytokine expression can also be induced by activation with Con A or phorbol ester plus ionophore, albeit to levels less than those observed with IgE plus antigen. In addition, long-term mast cell clones and primary cultures of bone marrow-derived mast cells specifically release IL-1, IL-4, and/or IL-6 bioactivity after activation. These findings suggest that in addition to their inflammatory effector function mast cells may serve as a source of growth and regulatory factors. The relationship of mast cells to cells of the T lymphocyte lineage is discussed.

Production of monocyte chemotactic and activating factor (MCAF) by human dermal fibroblasts in response to interleukin 1 or tumor necrosis factor

Normal human dermal fibroblasts rapidly expressed (less than 30 min.) considerable mRNA for monocyte chemotactic and activating factor (MCAF) and released high levels of biological activity in response to interleukin 1 (IL 1) or tumor necrosis factor (TNF). In contrast, cultured normal human keratinocytes did not express MCAF mRNA when stimulated with IL 1 or TNF. These results suggest the important role of dermal fibroblasts, the predominant cells in dermal connective tissue, in the recruitment of monocytes during inflammation. This is the first report of the induction of MCAF by IL 1 or TNF in any cell type.