A novel differentiation antigen on human monocytes that is specifically induced by granulocyte-macrophage colony-stimulating factor or IL-3

A mouse mAb (TOMS-1) was generated against human blood monocytes that had been cultured for 4 days in medium with recombinant human granulocyte-macrophage CSF (GM-CSF). TOMS-1 (IgG1) detected a unique cell surface Ag with a molecular mass of about 43 kDa under both reducing and nonreducing conditions. TOMS-1Ag was expressed on monocytes treated with GM-CSF, but not on fresh or untreated monocytes. This Ag was induced dose dependently during culture of monocytes with GM-CSF for more than 24 h, reaching a maximum level in 3 or 4 days. Treatment of monocytes with cycloheximide in the presence of GM-CSF blocked TOMS-1Ag induction completely, indicating that de novo protein synthesis was required for its expression. TOMS-1Ag was also induced by treatment of monocytes with IL-3, but not with other cytokines such as macrophage-CSF, IL-4, and IFN-gamma or stimulators including LPS, desmethyl muramyl dipeptide, and PMA. TOMS-1Ag expression induced by GM-CSF was up-regulated by IL-4, but down-regulated by IFN-gamma. TOMS-1Ag was not induced on lymphocytes, granulocytes, or AM by GM-CSF or appropriate stimuli. TOMS-1Ag was also not expressed on any cell lines of human leukemias or solid tumors examined. Thus, TOMS-1Ag is a monocyte-specific differentiation Ag induced by GM-CSF or IL-3. These results suggest that TOMS-1 should be useful for monitoring the process of monocyte differentiation by GM-CSF or IL-3.

A novel differentiation antigen on human monocytes that is specifically induced by granulocyte-macrophage colony-stimulating factor or IL-3

A mouse mAb (TOMS-1) was generated against human blood monocytes that had been cultured for 4 days in medium with recombinant human granulocyte-macrophage CSF (GM-CSF). TOMS-1 (IgG1) detected a unique cell surface Ag with a molecular mass of about 43 kDa under both reducing and nonreducing conditions. TOMS-1Ag was expressed on monocytes treated with GM-CSF, but not on fresh or untreated monocytes. This Ag was induced dose dependently during culture of monocytes with GM-CSF for more than 24 h, reaching a maximum level in 3 or 4 days. Treatment of monocytes with cycloheximide in the presence of GM-CSF blocked TOMS-1Ag induction completely, indicating that de novo protein synthesis was required for its expression. TOMS-1Ag was also induced by treatment of monocytes with IL-3, but not with other cytokines such as macrophage-CSF, IL-4, and IFN-gamma or stimulators including LPS, desmethyl muramyl dipeptide, and PMA. TOMS-1Ag expression induced by GM-CSF was up-regulated by IL-4, but down-regulated by IFN-gamma. TOMS-1Ag was not induced on lymphocytes, granulocytes, or AM by GM-CSF or appropriate stimuli. TOMS-1Ag was also not expressed on any cell lines of human leukemias or solid tumors examined. Thus, TOMS-1Ag is a monocyte-specific differentiation Ag induced by GM-CSF or IL-3. These results suggest that TOMS-1 should be useful for monitoring the process of monocyte differentiation by GM-CSF or IL-3.

Renaturation, purification, and characterization of human truncated macrophage colony-stimulating factor expressed in Escherichia coli

A human truncated macrophage colony-stimulating factor (M-CSF) encoding the amino acid residues from 3 to 153 of the native M-CSF was expressed by using a two-cistron expression system in Escherichia coli. The truncated M-CSF found in inclusion bodies was renatured and had CSF activity. Purification, which included a QAE-ZeTa preparative cartridge concentration step followed sequentially by HPLC on TSK-gel Phenyl-5PW and TSK-gel DEAE-5PW columns, gave an overall yield of 63.8%. The purified truncated M-CSF had a specific activity of 4 x 10(7) units/mg of protein. Peptide mapping of a lysylendopeptidase digest by reversed-phase HPLC confirmed the amino acid sequence predicted from the cDNA sequence. SDS-PAGE of the purified truncated M-CSF gave a single band at 17 kDa under reducing conditions and at 32 kDa under non-reducing conditions. Activated Thiol-Sepharose 6B column chromatography and other experiments failed to detect any free cysteine residue in spite of the existence of 7 cysteine residues in the truncated M-CSF subunit. These results indicate that it is a dimeric structure linked by one or more intermolecular disulfide bonds.

Macrophage colony-stimulating factor activity in malignant pleural effusions. Its augmentation by intrapleural interleukin-2 infusions

The activity of endogenous colony-stimulating factor (CSF) in malignant pleural effusions of lung cancer patients before and during daily intrapleural infusions of recombinant interleukin-2 (IL-2) was measured quantitatively by colony-forming bioassay and radioimmunoassay (RIA). Before therapy, malignant pleural effusions had various levels of CSF activities, and this CSF activity was neutralized almost completely by anti-M-CSF antibody. RIA also showed that the effusions contained various amounts of M-CSF. Daily intrapleural infusion of recombinant IL-2 caused significant increase in the CSF activities and M-CSF levels in pleural effusions. These results indicate that in vivo treatment with IL-2 induces production of endogenous M-CSF.

Decreased levels of IL-1 alpha and beta in psoriatic lesional skin

Interleukin 1 (IL-1), which mediates a wide range of biological activities, is thought to play an important role in many inflammatory and immunologic diseases. Normal human epidermal keratinocytes constitutively produce IL-1. Based on our previous data indicating decreased IL-1 activity in psoriatic scale extracts, in the present study, we measured immunoreactive IL-1 alpha and beta levels in the suction blister fluids as well as in the psoriatic scale extracts using enzyme immunoassay for IL-1 alpha and beta. The results showed that although similarly low levels of IL-1 alpha were detectable in the suction blister fluid from normal and psoriatic lesional skin, and that no IL-1 beta was found in most of the blister fluids, indicating that IL-1 alpha is major IL-1 species produced by human skin. As compared to those in the blister fluids, IL-1 alpha levels in the horny tissue extracts were found to be much higher, and they were significantly higher in the orthokeratotic stratum corneum extracts than in the psoriatic scale extracts. However, gel filtration of the orthokeratotic horny tissue extracts demonstrated that constituents for immunoreactive IL-1 alpha and beta were quite variable depending upon the source of the horny tissues. The present study has confirmed that IL-1 levels in the psoriatic scale extracts are decreased when compared with those in the orthokeratotic horny tissue possibly due to an increased epidermal proliferation activity associated with its high turnover rate. The role of IL-1 psoriatic lesions remains unknown.

Involvement of IL-6 in mesangial proliferative glomerulonephritis

In this study, we demonstrated that IL-6 was a possible autocrine growth factor for rat mesangial cells (MC). rIL-6 induced in vitro growth of rat MC at a concentration of 2 to 200 ng/ml and IL-6 activity was found in the supernatant of cultured rat MC. Northern blot analysis as well as in situ hybridization revealed that IL-6 mRNA was expressed in the cultured MC. Of urine samples from patients with mesangial proliferative glomerulonephritis (PGN) 50% were found to contain significant IL-6 activity (ranging from 30 to 126 pg/ml). Urine samples from other type of primary glomerular diseases such as minimal change nephrotic syndrome or healthy volunteers contained no detectable IL-6 activity. Only 2 of 27 urine samples from membranous nephropathy contained detectable amount of IL-6. Furthermore, there was some relationship between the levels of urine IL-6 and the progressive stage of PGN. Finally, by immunohistochemical staining using an anti-IL-6 mAb, it was shown that MC in the affected glomeruli of PGN patients produced IL-6, whereas MC obtained from the patients with membranous nephropathy, minimal change nephrotic syndrome or normal kidney were not found to produce IL-6. These data suggest that deregulated production of IL-6 is involved in PGN and the measurement of urine IL-6 is helpful for the differential diagnosis of PGN as well as for monitoring the progression of PGN.

Involvement of IL-6 in mesangial proliferative glomerulonephritis

In this study, we demonstrated that IL-6 was a possible autocrine growth factor for rat mesangial cells (MC). rIL-6 induced in vitro growth of rat MC at a concentration of 2 to 200 ng/ml and IL-6 activity was found in the supernatant of cultured rat MC. Northern blot analysis as well as in situ hybridization revealed that IL-6 mRNA was expressed in the cultured MC. Of urine samples from patients with mesangial proliferative glomerulonephritis (PGN) 50% were found to contain significant IL-6 activity (ranging from 30 to 126 pg/ml). Urine samples from other type of primary glomerular diseases such as minimal change nephrotic syndrome or healthy volunteers contained no detectable IL-6 activity. Only 2 of 27 urine samples from membranous nephropathy contained detectable amount of IL-6. Furthermore, there was some relationship between the levels of urine IL-6 and the progressive stage of PGN. Finally, by immunohistochemical staining using an anti-IL-6 mAb, it was shown that MC in the affected glomeruli of PGN patients produced IL-6, whereas MC obtained from the patients with membranous nephropathy, minimal change nephrotic syndrome or normal kidney were not found to produce IL-6. These data suggest that deregulated production of IL-6 is involved in PGN and the measurement of urine IL-6 is helpful for the differential diagnosis of PGN as well as for monitoring the progression of PGN.

Synthesis of a novel cytokine and its gene (LD78) expressions in hematopoietic fresh tumor cells and cell lines

The gene coding for the protein LD78 was isolated from stimulated human tonsillar lymphocytes by differential hybridization. The gene product consisted of 92 amino acids with characteristics of cytokines. LD78 gene transcripts were detected in eight of eight fresh samples of cells from patients with acute nonlymphocytic leukemia (ANLL) by Northern blot analysis. ANLL cells with monocytic features gave the strongest bands. RNA transcripts were found in two of three samples of cells from patients with adult T cell leukemia (ATL), eight of nine samples from patients with acute lymphocytic leukemia (ALL) of B cell lineage, and one of the three samples from patients with T cell ALL. KG-1, HL-60, HUT 102, MT-2, and MJ cell lines expressed the LD78 gene constitutively. The LD78 protein was detected in culture supernatants and cell lysates of HUT 102, MT-2, MJ, and fresh ATL cells by Western blot analysis. This protein was not found in culture supernatants or cell lysates of monocytic leukemia cells and HL-60 cells, although LD78 transcripts were found in those cells. The discrepancy between gene and protein expression might be explained by the stability of the mRNA. Thus, the protein may be involved in the neoplastic transformation of hematopoietic cells.

Identification of a specific receptor for interleukin-1 on rat bone marrow cells

The interleukin-1 (IL-1) receptor on rat bone marrow cells was investigated using 125I-labeled IL-1 alpha and -1 beta. These radiolabeled ligands bound to the rat bone marrow cells in a specific and saturable manner with Kd values of 0.36 +/- 0.072 nM and 1.9 +/- 0.27 nM, respectively. In a competitive binding experiment, IL-1 alpha and -1 beta inhibited the binding of 125I-IL-1 alpha with Ki values of 0.35 +/- 0.041 nM and 2.9 +/- 1.0 nM. The binding of 125I-IL-1 beta was inhibited by IL-1 alpha and -1 beta with Ki values of 0.27 +/- 0.020 nM and 0.74 +/- 0.12 nM. In cross-linking experiments, 125I-IL-1 alpha was covalently incorporated into two proteins of 163 kDa and 63 kDa. These results suggested the presence of two binding proteins for IL-1 on the rat bone marrow cells.

Interleukin-1 beta rather than lymphotoxin as the major bone resorbing activity in human multiple myeloma

Human myeloma cells were purified from bone marrow aspirates from four patients having advanced myeloma, including one with common acute lymphoblastic leukemia antigen-positive myeloma. All of these myelomas had marked bone lytic lesions. From the culture supernatants of these purified myeloma cells, bone-resorbing activities were significantly revealed by 45Ca-release bone resorption assay, and IL-1 activities were also detected by IL-1 bioassay (mouse thymocyte comitogenic assay). Sandwich enzyme immunoassay for IL-1 alpha or IL-1 beta revealed that IL-1 beta was responsible for IL-1 activity of these culture supernatants. Furthermore, the bone resorbing activities of these culture supernatants were completely neutralized by pretreatment of anti-IL-1 beta, but not anti-IL-1 alpha antibody. By Northern blot analysis, IL-1 beta mRNA was identified from these myeloma cells. Therefore, it is concluded that myeloma cells produce IL-1 beta, which acts as bone-resorbing activity in multiple myeloma.

Site-specific mutagenesis of the human interleukin-1 beta gene: the role of arginine residue at the N-terminal region

Using the expression system for site-specific mutagenesis in Escherichia coli, we have made deletion mutants at the N-terminal or C-terminal region of human interleukin-1 beta (IL-1 beta) consisting of 153 amino acids. The truncated mutants showed that at least 147 amino acids (numbers 4-150) in IL-1 beta are necessary for the exertion of biological activity. When we changed the arginine at the 4th position (Arg4) in IL-1 beta to other specific amino acids, there was a marked difference in the relative extent of biological and receptor binding activities among the mutants. The order of the mutants was Arg4 = Lys4 greater than Gln4 greater than Gly4 = des-Arg4 greater than Asp4. Our results demonstrate that the arginine residue at the 4th position in IL-1 beta is important, but not essential, for IL-1 beta to exhibit its biological and receptor binding activities, and the positive charge at this site plays a key role for IL-1 beta to exert the activities.

Site-specific mutagenesis of the human interleukin-1 beta gene: structure-function analysis of the cysteine residues

Human interleukin-1 beta (IL-1 beta) has two cysteines located at amino acid residues 8 and 71 of the mature protein consisting 153 amino acids. To clarify the role of these characteristic cysteine residues in IL-1 beta, at first, an expression plasmid for site-specific mutagenesis has been constructed by inserting the ori and intergenic region of phage f1 into the IL-1 beta expression vector. The plasmid can be used not only for isolation of the modified IL-1 beta gene but for expression of the mutant protein in Escherichia coli. Using this plasmid, each of the cysteine codons in IL-1 beta gene was changed to serine or alanine codon, or deleted. The modified IL-1 beta showed that the two cysteine residues in IL-1 beta are not essential for biological activity but not to be eliminated for the maintenance of the functional structure of IL-1 beta.

In vitro production of human interleukin 1 alpha and interleukin 1 beta by peripheral blood mononuclear cells examined by sensitive sandwich enzyme immunoassay

The in vitro production of human interleukin 1 alpha (hIL 1 alpha) and interleukin 1 beta (hIL 1 beta) by peripheral blood mononuclear cells was examined by sensitive sandwich enzyme immunoassays which could discriminate hIL 1 alpha and hIL 1 beta without cross-reaction with human IL2. In culture supernatants of mononuclear cells, two components were detected by sandwich enzyme immunoassay for hIL 1 alpha or hIL 1 beta. The molecular weight of one component was shown to be equal to that of recombinant hIL 1 alpha or hIL 1 beta by gel filtration. The elution volume of the other component corresponded to a molecular weight of about 30,000. The sum of the two components for both hIL 1 alpha and hIL 1 beta in culture supernatants of peripheral blood mononuclear cells from healthy subjects increased 1.7 to 38-fold by Escherichia coli lipopolysaccharide. The sum of the two components for hIL 1 beta was 13 to 97-fold larger than that for hIL 1 alpha.

Sandwich enzyme immunoassay for human interleukin-1 beta (hIL-1 beta) in urine

A highly sensitive sandwich enzyme immunoassay for human interleukin-1 beta (hIL-1 beta) in urine is described. Rabbit anti-hIL-1 beta IgG-coated polystyrene balls were incubated with urine samples and subsequently with affinity-purified rabbit anti-hIL-1 beta Fab'-horseradish peroxidase conjugate. After washing, the peroxidase activity bound to the polystyrene ball was assayed by fluorimetry using 3-(4-hydroxyphenyl)propionic acid as a substrate. The detection limit of hIL-1 beta was 0.5 pg/tube (30 amol/tube) or 5 ng/1 of urine when 0.1 ml of urine sample was used. The molecular weight of hIL-1 beta in normal urine was shown to be 17,000 by gel filtration, and levels of urine hIL-1 beta in healthy subjects aged 19-87 yr were 0-146 ng/1 or 0-88 ng/g of creatinine.