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

Inside, outside, upside down: damage-associated molecular-pattern molecules (DAMPs) and redox

Immune responses are initiated and perpetuated by molecules derived from microorganisms pathogen-associated molecular-pattern molecules or from the damage or death of host cells [damage-associated molecular-pattern (DAMP) molecules]. Many DAMPs are nuclear or cytosolic proteins with defined intracellular function that, when released outside the cell following tissue injury, move from a reducing to an oxidizing milieu resulting in their functional denaturation. Here, we discuss the consequences of DAMP oxidation on the outcome of acute inflammation. We also suggest that, outside the cell, DAMPs might adopt novel conformations or alter the redox of the extracellular environment to more closely mimic the internal one, thereby avoiding oxidation-mediated inactivation and promoting pathology. We propose that chronic inflammation associated with autoimmunity, chronic viral infection and cancer is probably mediated by persistent release and function of DAMPs, promoting and promoted by a disordered redox environment.

Core and surface mutations affect folding kinetics, stability and cooperativity in IL-1 beta: does alteration in buried water play a role?

Interleukin-1 beta (IL-1 beta) is a cytokine and a member of the beta-trefoil superfamily of protein structures. An interesting feature in the folding of IL-1 beta, shared with some other members of the same topological family, is the existence of a slow step in folding to the native conformation from a discrete intermediate. Wanting to probe the nature of this slow step in the folding of WT IL-1 beta (tau(1)=45 seconds), we made ten sequence variants of IL-1 beta (L10A, T9Q, T9G, C8S, C8A, N7G, N7D, L6A, R4P, and R4Q), where all mutations are located along strand 1. This strand is not protected from hydrogen exchange until late in folding. Most of the mutations showed little effect on the kinetics of folding for IL-1 beta. However, C8 is clearly involved in both the late and the early steps in folding, while sequence variants at L10 and L6 affect only late events in folding. The value of the slowest relaxation time, tau(1), which is associated with the rate of native protein formation, increased for the refolding of C8S, while C8A, L6A, and L10A showed smaller but systematic increases in the value of tau(1.)For both C8S and C8A, the value of the step associated with formation of the intermediate, tau(2), was independent of denaturant concentration. In addition, mutations in the hydrophobic core (L10A, C8A, C8S, and L6A) and, surprisingly, along the surface (T9G, T9Q, and N7G) alter the stability. The most destabilizing mutations show changes in equilibrium unfolding cooperativity, which is atypical for destabilizing mutations in IL-1 beta. Crystallographic studies indicate that mutations along strand 1 may alter the number of ordered water molecules within the core. Thus, side-chain replacement in this region can disrupt essential main-chain interactions mediated by ordered water contacts in a highly cooperative network of hydrogen bonding.

Role of interleukin-1beta in the modulations of cytochrome P450 and heme metabolism in rat liver

The effect of recombinant human interleukin-1beta (IL-1beta) on the modulation of hepatic cytochrome P450 (P450) was investigated by in vivo subcutaneous dosing studies in male Sprague-Dawley rats. To assess the effect of IL-1beta on heme metabolism, we determined the delta-aminolevulinic acid synthetase (delta-ALAS) and heme oxygenase activities in the liver. IL-1beta suppressed the microsomal total P450 and heme contents and delta-ALAS activity in the liver. In contrast, microsomal heme oxygenase activity was significantly increased by the IL-1beta treatments. Western blot analysis and marker enzyme activities for individual P450 isoforms demonstrated that IL-1beta suppressed CYP2C6, 2C13, 2E1, and 3A2, whereas CYP2A, 2B1/2, 2C11, and 4A1 were not influenced by the treatments. IL-1beta inhibited both allylisopropylamide- and phenobarbital-inducible delta-ALAS activities in the liver. These results indicate that IL-1beta has differential effects on the constitutive P450, and also on delta-ALAS and heme oxygenase activities in rat liver. Thus, the modulation of hepatic P450 by IL-1beta is complex, and IL-1beta may be involved in the regulation of both apoprotein synthesis for each P450 isoform and the heme pools in the liver.

Proteases involved in the metabolic degradation of human interleukin-1beta by rat kidney lysosomes

The in vitro metabolic degradation of human interleukin (IL)-1beta was studied using lysates of rat kidney lysosomes, and proteases involved in the degradation were identified. In the study of IL-1beta degradation, fluorescein isothiocyanate (FITC)-labeled IL-1beta was used as a substrate. The maximal degradation of IL-1beta occurred at pH 3.0, and the reaction was proportional to the lysosomal protein concentration and time of incubation. The degradation was stimulated by the addition of L-cysteine. The reaction was not inhibited by phenylmethanesulfonyl fluoride or EDTA, indicating that serine proteases or metalloproteases do not play a major role in the degradation process. N-Ethylmaleimide, leupeptin and E-64, inhibitors of thiol protease, inhibited the degradation of IL-1beta, by 59%-70%. Pepstatin A, an inhibitor of carboxyl protease, inhibited the degradation by 58%. Combinations of thiol and carboxyl protease inhibitors nearly completely inhibited the degradation. Bio-Gel P-10 gel filtration chromatography of in vitro reactants confirmed the ability of lysosomal proteases to degrade IL-1beta and revealed four to five peaks of degradation products. Taken together, these results indicate that thiol protease and carboxyl protease play an important role in the IL-1beta degradation process by kidney lysosomes. Leupeptin and E-64 dose dependently inhibited both cathepsin B and cathepsin L activities, and pepstatin A strongly inhibited cathepsin D activity in rat kidney lysosomes. The present results suggest that cathepsin B, cathepsin L, and cathepsin D in kidney lysosomes are involved in the metabolic degradation of human IL-1beta.

The effectiveness of active specific immunotherapy using interferon-gamma-gene-transduced tumor cells in a murine tumor model

Active specific immunotherapy was examined in BALB/c mice using sonicated tumor extract(SE) from plasmacytoma MOPC104E or interferon-gamma-(IFN-gamma)-gene-transduced MOPC104E (Mu gamma), employing interleukin-1 (IL-1) as an adjuvant. Subcutaneous (s.c.) MOPC104E tumor growth was significantly suppressed in mice given a single preimmunization of IL-1 plus Mu gamma-SE, 9 days prior to inoculation, whereas the tumor growth in mice similarly pretreated with IL-1 alone or IL-1 plus MOPC104E-SE(MOPC-SE) was not affected; the mean tumor diameters on day 21 being 6.8 mm, 15.3 mm, and 13.2 mm, respectively. Two-dose preimmunization with Mu gamma-SE alone or IL-1 alone given 10 and 7 days prior to s.c. inoculation also resulted in profound suppression of tumor growth compared to the control. As postsurgical immunization, MOPC104E cells were injected into the foot pads of mice, followed by amputation of the tumor-bearing foot 20 days later, then treatment with IL-1 plus MOPC-SE or IL-1 plus Mu gamma-SE on days 4, 7, and 10 after the amputation. The mean survival of the mice treated with IL-1 plus Mu gamma-SE was significantly prolonged compared to that of the mice treated with IL-1 plus MOPC-SE, at 90.3 days vs 40.9 days, respectively (P < 0.05 by the Cox-Mantel test). These results suggest that SE prepared from IFN-gamma-gene-transduced MOPC104E is more effective for active specific immunotherapy than SE prepared from MOPC104E.

Effects of monoclonal antibodies to specific epitopes of rat interleukin-1 beta (IL-1 beta) on IL-1 beta-induced ACTH, corticosterone and IL-6 responses in rats

Recently, we developed a panel of monoclonal antibodies (MoAbs) to rat IL-1 beta and found that MoAbs binding to the aminoacid sequences 66-85 and 123-143 of mature rIL-1 beta inhibited the binding of rIL-1 beta to murine EL4 cells. Here we study whether MoAbs to these and other domains of IL-1 interfere with the biological effects of rIL-1 beta in adult male rats in vivo. Administration of rIL-1 beta (1 or 5 micrograms/kg i.v.) enhanced the plasma concentrations of ACTH, corticosterone (CORT) and of IL-6 in a time- (0.5-4 h) and dose-dependent manner. Because 2 h after 5 micrograms/kg i.v., all three parameters were consistently elevated, this dose and time interval was used for further studies. Prior to injection, rIL-1 beta was incubated alone or in the presence of a MoAb (10 mg/kg) for 30 min at 37 degrees C or at 4 degrees C. Plasma ACTH, CORT and IL-6 responses to these mixtures are compared to those obtained after preincubation of rIL-1 beta with a non-IL-1 binding MoAb (PEN7). SILK 3, a MoAb that binds to the 66-85 domain of rIL-1 beta, reduced the ACTH and IL-6 responses by 48 and 45% respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Refined crystal structure of the interleukin-1 receptor antagonist. Presence of a disulfide link and a cis-proline

Interleukin-1 (IL-1) molecules are cytokines involved in the acute-phase response against infection and injury. Three naturally occurring IL-1 molecules are known, two agonists: IL-1 alpha and IL-1 beta, and one antagonist, the IL-1 receptor antagonist (IL-1ra). Although IL-1 action protects the organism by enhancing the response to pathogens, its overproduction can lead to pathology and has been implicated in disease states that include septic shock, rheumatoid arthritis, graft versus host disease and certain leukemias. The crystal structure of IL-1ra has been solved at 0.21-nm resolution by molecular replacement using the IL-1 beta structure as a search model. The crystals contain two independent IL-1ra molecules which are very similar. IL-1ra has the same fold as IL-1 alpha and IL-1 beta. The fold consists of twelve beta-strands which form a six-stranded beta-barrel, closed on one side by three beta-hairpin loops. Cys69 and Cys116 are linked via a disulfide bond and Pro53 has been built in the cis-conformation. Comparison of the IL-1ra structure with the IL-1 alpha and IL-1 beta structures present in the Protein Data Bank shows that a putative receptor interaction region, involving the N-terminus up to the beginning of strand beta 1 and the loops D and G, is very different in the three IL-1 molecules. Other putative interaction regions, as identified with mutagenesis studies, are structurally conserved and rigid, allowing precise and specific interactions with the IL-1 receptor.

The induction of specific antitumor immunity by in vivo treatment with interleukin-1 and sonicated tumor extract in a murine model

BALB/c mice were pretreated intraperitoneally with interleukin-1 (IL-1) and sonicated tumor extract (SE) from plasmacytoma MOPC104E, 10, 7, and 4 days prior to the intraperitoneal or subcutaneous inoculation of MOPC104E cells, following which significant suppression was observed. The mean survival time and tumor diameter on day 21 were 46.7 days and 0 mm, respectively, in contrast to the 20.9 days and 20.4 mm of control mice. Mice pretreated with IL-1 and SE from MOPC104E (MOPC-SE) were not suppressed following fibrosarcoma MethA inoculation, which indicates the tumor specificity of immunity in this model. This systemically operating antitumor immunity was also achieved by the intramuscular administration of IL-1, or when tumor challenge was performed on day 7 or 14. Moreover, MOPC104E-specific delayed-type hypersensitivity was detected in these mice. The results of this study suggest the possibilities of a new type of active specific immunotherapy, which could prove useful as postsurgical adjuvant therapy for cancer patients.

The synergistic antitumor effect of recombinant interleukin-1 and low-dose of cyclophosphamide in tumor-bearing mice

Intraperitoneal (i.p.) treatment of MOPC104E ascitic tumor-bearing BALB/c mice with interleukin-1 (IL-1) followed by a low dose of cyclophosphamide (CPA) resulted in synergistic prolongation of their survival time. This antitumor effect was abolished when administration of CPA preceded that of IL-1. The combined i.p. therapy also eradicated subcutaneous (s.c.) tumors, indicating a systemically operating antitumor mechanism. In Winn assay, splenocytes from MOPC104E-bearing mice treated with the combined therapy completely suppressed the growth of MOPC104E cells, but not that of another syngeneic tumor cell line, RL female-8 cells. This tumor-neutralizing activity was completely abrogated by treatment with anti-asialo-GM1 or anti-Thy1.2 and complement, and reduced by treatment with anti-Lyt2.2 and complement. Treatment of splenocytes with 1-leucine methyl ester (Leu0Me), which depletes natural killer (NK) cells and macrophages in vitro, did not affect the neutralizing activity.

Binding of type I IL-1 beta receptor fragment 151-162 to interleukin-1 beta

The relevance of hydropathically complementary sequences in ligand receptor interactions has been evaluated in the interleukin-1 beta/receptor type I case. Computer assisted comparison of the hydropathic profiles of IL-1 beta and its receptor (type I) identified residues 88-99 in IL-1 beta and 151-162 in the receptor as the sequences pair characterized by the highest level of hydropathic complementarity. These fragments, once produced by chemical synthesis and derivatized with biotin, displayed specific recognition properties for each other, as detected by solid phase binding assays. Binding between the two fragments occurred independently from the assay format, was saturable and specifically inhibited by unlabeled peptides. Receptor fragment (151-162) derivatized with biotin recognized also full length recombinant IL-1 beta, and binding was inhibited to 50% in the presence of 3 microM IL-1 beta (88-99) peptide. Interaction specificity was further confirmed by the non competitive effect on the interaction of a sequence scrambled IL-1 beta (88-99) peptide. In a similar way, full length biotinylated IL-1 beta recognized immobilized IL-1 beta receptor fragment (151-162), and this interaction was diminished in the presence of unlabeled receptor fragment or IL-1 beta Results indicate that IL-1 beta receptor fragment (151-162) binds IL-1 beta recognizing the IL-1 beta (88-99) sequence, thus suggesting a possible role of these fragments in the protein/receptor recognition surface.

Structure of an interleukin-1 beta mutant with reduced bioactivity shows multiple subtle changes in conformation that affect protein-protein recognition

Site-specific mutagenesis was used to obtain the human interleukin-1 beta mutant protein with glycine substituted for threonine at position 9 (IL-1 beta Thr9Gly). The mutant maintains receptor binding but exhibits significantly reduced biological activity. The crystal structure of IL-1 beta Thr9Gly has been determined at 2.4-A resolution by molecular replacement techniques and refined to a crystallographic R-factor of 19.0%. IL-1 beta Thr9Gly crystallizes in a different space group (P6(5)22) than does native IL-1 beta (P4(3)); thus the molecules pack differently. Their overall structure is similar, nevertheless, with both composed of 153 amino acids which form 12 antiparallel beta-strands. However, significant conformational differences both close to and far from the site of the mutation may explain the mutant's altered properties.

Sequential immunotherapy using interleukin-1 followed by interleukin-2 of ascitic MOPC104E-bearing mice

This study shows that intraperitoneal injection of interleukin-1 (IL-1), followed by interleukin-2 (IL-2), can effectively eradicate murine ascitic tumor cells. This antitumor effect of IL-1 and IL-2 was abolished when administration of IL-2 preceded that of IL-1. Solid tumors inoculated subcutaneously (s.c.) into the back of mice were also sensitive to this combined i.p. therapy, indicating a systemically-operating antitumor mechanism. Splenocytes from tumor-bearing mice treated with IL-1 followed by IL-2 showed a strong tumor-neutralizing activity. The population responsible proved to be Lyt2.2 (CD8)-positive cells.

Interleukin-1 beta-specific partial agonists defined by site-directed mutagenesis studies

Monocyte-derived interleukin 1 (IL-1) mediates a wide range of biological effects including destruction of the cartilage matrix in articular diseases such as rheumatoid and osteoarthritis. To elucidate further the relationships between protein structure and biological activities, we have analyzed the sequence of several IL-1 polypeptides using the algorithm of Parker, the hydrophobic cluster analysis method and published structural data. This led us to identify several residues that seemed to be strictly topologically conserved, with respect to identifiable secondary structures features, although this was not readily apparent from sequence alignments. We performed site-directed mutagenesis on some of these conserved residues, as well as on those predicted to occur in external loops of the polypeptide. Human IL-1 beta mutant polypeptides were expressed in Escherichia coli in soluble form and purified to homogeneity by anion-exchange and gel-filtration chromatography. Their biological effects (binding to EL4-6.1 murine thymocytes, Raji human B cells and rabbit chondrocytes cells, lymphocyte activation, neutral protease induction, proteoglycan degradation and synthesis) have been determined. Among the 20 IL-1 beta mutant polypeptides we present here, four showed a markedly reduced activity in cartilage matrix assays without any significant change in their binding to the cartilage matrix cells (chondrocytes). Furthermore, some of these mutants were specific partial agonists of the effects of IL-1 on connective tissue since they have a low affinity for thymocytes.

Chemical modification of interleukin-1 beta: biochemical characterization of a carbodiimide-catalyzed intramolecular cross-linked protein

We have modified recombinant human Interleukin-1 beta using 1-ethyl-3(3-dimethylaminopropyl)-carbodiimide at pH 6.5, resulting in the formation of an internally cross-linked protein. The major product (30% yield) of the reaction (17 kD; pI = 6.2) was purified and fully characterized by peptide mapping using Endoproteinase Lys C. When digests were conducted under nondenaturing conditions, we found that the modified protein is different from the native protein. The native protein yielded 14 peptides after digestion, whereas only two large peptides and a tetrapeptide, Asn-Tyr-Pro-Lys, were released from the cross-linked protein (i.e., cleavage occurs only at residues Lys88 and Lys92). Using gel filtration, the two peptides were found to co-elute as a single species (15 kD), which represent a noncovalent complex of the amino terminal and C-terminal portions of the molecule. Further analysis of the modified protein by peptide mapping under denaturing conditions and by FAB MS analysis showed that Glu111 and Lys138 were internally cross-linked. The cross-linked protein had bioactivity (T-cell proliferation), fluorescence, and circular dichroism spectra similar to native IL-1 beta. In contrast, while having similar secondary structure, the digested cross-linked protein had less than 1% of T-cell proliferative activity of the undigested protein. These data show that the structural integrity surrounding and perhaps including the Asn-Tyr-Pro-Lys region may be crucial for the biological activity of rIL-1 beta and may be important for the binding of IL-1 to its receptor.

Functional implications of interleukin-1 beta based on the three-dimensional structure

The molecular structure of interleukin-1 beta, a hormone-like cytokine with roles in several disease processes, has been determined at 2.0 A resolution and refined to a crystallographic R-factor of 0.19. The framework of this molecule consists of 12 antiparallel beta-strands exhibiting pseudo-3-fold symmetry. Six of the strands make up a beta-barrel with polar residues concentrated at either end. Analysis of the three-dimensional structure, together with results from site-directed mutagenesis and biochemical and immunological studies, suggest that the core of the beta-barrel plays an important functional role. A large patch of charged residues on one end of the barrel is proposed as the binding surface with which IL-1 interacts with its receptor.

Antitumor effector mechanism of interleukin-1 beta at a distant site in the double grafted tumor system

Recombinant human interleukin-1 beta (IL-1 beta) inhibited the growth of not only the right, but also the left non-treated tumor in a double grafted tumor system. Since the antitumor activity of IL-1 beta against the right and left tumors was not seen in nude mice, lymphocytes have a key role in the antitumor effect of intratumoral administration of IL-1 beta. TIL (tumor-infiltrating leukocytes) obtained from left and right side tumors treated with IL-1 beta were examined by Winn assay for their antitumor activity against Meth-A sarcoma in BALB/c mice. TIL from the right side clearly inhibited the growth of admixed Meth-A cells, but control TIL did not. Spleen cells and right and left regional lymph node cells prepared from IL-1-treated mice were examined for Lyt-1, Lyt-2 and L3T4 phenotypes. The number of Lyt-1-positive lymphocytes increased in the spleen and in the right regional lymph nodes after intratumoral administration of IL-1. Isolated tumor cells obtained from the right tumor treated with IL-1 beta and the left side tumor on day 6 were cultured in RPMI 1640 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 and macrophage chemotactic factor activities were detected in the culture media from IL-1-treated tumor tissues cultured for 24 h. Neither significant neutrophil nor macrophage chemotactic activity was detected in the media from untreated tumor tissues. These results suggest that intratumoral administration of IL-1 first induces neutrophils and macrophages in the right tumor, then Lyt-1-positive cells in the right regional lymph nodes and in the spleen, and subsequently induces macrophages in the left, non-treated tumor.

Recombinant human interleukin-1 beta analogue as a regulator of hematopoiesis in patients receiving chemotherapy for urogenital cancers

Ten patients with advanced urologic cancers who were scheduled to receive at least two courses of chemotherapy were enrolled in this trial. Fifty thousand units of recombinant human interleukin-1 (IL-1) beta analogue OCT-43 (Otsuka Pharmaceutical Co., Ltd., Tokyo, Japan) was administered subcutaneously only once or twice when severe neutropenia (less than 500/microliters) continued for 2 consecutive days. In eight patients, OCT-43 was not injected in the first course of chemotherapy as a control, but was injected in the second course. The durations of leukocytopenia (less than 2000/microliters) and neutropenia (less than 1000/microliters) were significantly shortened in the second course compared with those in the first course in those eight patients. Recovery of neutrophil number from the lowest number was also significantly faster in the second course. Thus, OCT-43 was considered to have hematopoietic activities. However, single or double injection of OCT-43 did not affect the numbers of eosinophilic or basophilic granulocytes, monocytes, or platelets. Adverse effects associated with OCT-43 injections were high fever and chills, but they were controlled by indomethacin.

Reduction of biological activity of murine recombinant interleukin-1 beta by selective deamidation at asparagine-149

A biologically active preparation of murine recombinant interleukin-1 beta (mIL-1 beta) from Escherichia coli cell lysates contained tow forms of mIL-1 beta with pI 8.7 and pI 8.1, respectively. Treatment with 0.1 M Tris, pH 8.5, at 37 degrees C for 35 h converted the pI 8.7 form to the pI 8.1 form by the selective deamidation of an asparagine residue (Asn149) in the mIL-1 beta molecule. Deamidated mIL-1 beta had 3- to 5-fold lower co-mitogenic activity and receptor affinity than the unmodified form.

Structure-function relationship of interleukin-1 giving new insights for its therapeutic potential

The pleiotropic activities of IL-1 have fostered a series of studies on the structure-function relationship in these proteins. In fact, the attempt to dissociate different biological functions of IL-1 should simplify its therapeutic use. About human IL-1 beta, which has been more extensively studied in this respect, enzymatic cleavage of the precursor protein to generate the mature polypeptide appears necessary for its full biological activity. The almost complete integrity of the mature IL-1 beta protein is also required for its ability to bind to the receptor and trigger cellular functions. However, by the use of monoclonal antibodies and recombinant or synthetic peptides, it has been possible to map some IL-1 beta regions important for different activities. Both N-terminal and C-terminal fragments are important for receptor binding. A domain around amino acids 187-204 is apparently involved in the hyperalgesic effects of IL-1 beta. Finally, the fragment in position 163-171 appears to be responsible for a restricted series of the IL-1 beta activities, mainly directed to the immune system, although irrelevant for inflammation-related effects and unable of binding to the IL-1R. It is thus possible, within the sequence of a cytokine, to isolate selectively active domains. This will give us new tools for new therapeutic approaches. Thus, IL-1 might be the prototype of a new generation of cytokines developed with the goal of stimulating specific biological activities without activating the cascade effects which are typical for many cytokines.

Crystallographic refinement of interleukin 1 beta at 2.0 A resolution

The structure of human recombinant interleukin 1 beta (IL-1 beta) has been refined by a restrained least-squares method to a crystallographic R factor of 17.2% to 2.0 A resolution. One-hundred sixty-eight solvent molecules have been located, and isotropic temperature factors for each atom have been refined. The overall structure is composed of 12 beta-strands that can best be described as forming the four triangular faces of a tetrahedron with hydrogen bonding resembling normal antiparallel beta-sheets only at the vertices. The interior of this tetrahedron is filled by hydrophobic side chains. Analysis of sequence alignments with IL-1 beta from other mammalian species shows the interior to be very well conserved with the exterior residues markedly less so. There does not appear to be a clustering of invariant amino acid side chains on the surface of the molecule, suggesting an area of interaction with the IL-1 receptor. Comparison of the IL-1 beta structure with IL-1 alpha sequences indicates that IL-1 alpha probably has a similar overall folding as IL-1 beta but binds to the receptor in a different fashion. The three-dimensional structure of the IL-1 beta is analyzed in light of what has been suggested by previously published work on mutants and fragments of the molecule.

Antitumor effect of interleukin-1 beta in the double grafted tumor system

The antimetastatic effect of recombinant human interleukin-1 beta (rIL-1 beta) in a new experimental mouse model was studied. Intratumoral administration of IL-1 beta strongly inhibited the growth of Meth-A solid tumors in male BALB/c mice and led to a complete regression of tumors and resistance to reinoculated tumor. Subsequently, the anti-metastatic effect of IL-1 beta was examined in the double grafted tumor system, in which mice first received simultaneous intradermal inoculations of Meth-A in both right (10(6) cells) and left (2 X 10(5) cells) flanks and were then injected with 0.2 micrograms of IL-1 beta in the right tumor on days 3, 4 and 5. IL-1 beta significantly inhibited the growth of the left, non-treated tumor. When mice received only an inoculation of Meth-A (2 X 10(5) cells) in the left flank and were injected subcutaneously with IL-1 beta into the right flank on day 3 (single tumor system), there was no inhibition of the growth of the left, non-treated tumor. These findings suggest that intratumoral IL-1 beta immunotherapy in one region has an effect on tumor growth in another region. Immunized spleen cells were taken from mice which had been cured by the intratumoral administration of IL-1 beta. Adoptive transfer of the immunized spleen cells caused the complete regression of Meth-A tumors. These results suggest that intratumoral administration of IL-1 beta might induce cytotoxic cells in the left non-treated tumor of the double grafted tumor system and bring about the regression of metastatic tumors.(ABSTRACT TRUNCATED AT 250 WORDS)

Interleukin-1 potentiates granulopoiesis and thrombopoiesis by producing hematopoietic factors in vivo

In vivo administration of recombinant human interleukin-1 beta (rHu IL-1 beta) selectively enhanced the recovery from granulocytopenia and thrombocytopenia caused by whole body irradiation, in a dose dependent manner. Since IL-1 itself in vitro had no colony-stimulating activity (CSA), we studied whether IL-1 can produce hematopoietic factors in vivo, which in turn will promote granulopoiesis and thrombopoiesis. Serum from IL-1 injected mice showed marked granulocyte/macrophage CSA (GM-CSA), but little megakaryocyte CSA (Meg-CSA). Interestingly, strong megakaryocyte potentiator (Meg-POT) activity was detected in the serum. Further analysis of the serum by gel filtration chromatography showed that Meg-POT activity could be eluted in different fractions from GM-CSA. Since erythropoietin which is known to stimulate erythropoiesis also exhibited remarkable Meg-POT activity, serum from IL-1 injected mice were assayed for erythroid CSA. We found that unlike erythropoietin the serum showed no erythroid CSA. Taken together, these results suggest that IL-1 may potentiate granulopoiesis and thrombopoiesis by producing at least two distinct types of hematopoietic growth factors in vivo, namely granulocyte/macrophage colony-stimulating factor and a thrombopoietin-like factor.