Lymphocyte-activating Factor Activity Research Articles

IMPACT OF RONCOLEUKIN (RIL-2) ON THE LYMPHOCYTE-TRIGGERING ACTIVITY OF MACROPHAGES AFTER TRAUMATIC BRAIN INJURY IN VARIOUSLY AGED RATS

IL-1β is involved in both brain damage process and the mechanisms of brain regeneration processes. The goal of the present research is to measure the change in the production of lymphocyte-activating factor (LAF) after experimental traumatic injury (TBI) in variously aged rats and evaluate the possibility to correct LAF production with roncoleukin (rIL-2). LAF activity in the supernatants of peritoneal macrophages of injured rats was measured by its ability to have comitogenic effect on the proliferation of rat thymocytes stimulated by suboptimal lectin doses. LAF stimulation index was defined as ratio of stimulated to unstimulated levels of LTF. Results and discussion. The strongest suppression of microphages’ cytokine-producing function was found in older rats after TBI. rIL-2 injection significantly reversed the injuries caused by TBI even in older rats. These data confirm that exogenic IL-2 is able to activate the functional characteristics of innate immunity cells and that is has a normalizing effect on the immune cells of the older animals.

The definition of lymphocyte activating factor: giving a helping hand to serendipity.

The definition of lymphocyte activating factor: giving a helping hand to serendipity.

Does interleukin-1 mediate tumour necrosis factor alpha-induced fever in rabbits?

We investigated the humoral mechanisms involved in tumour necrosis factor alpha (TNF alpha)-induced fever in rabbits. No change in lymphocyte-activating factor activity was detected in serum drawn during TNF alpha-induced fever. The pyrogenic activity of recombinant rabbit interleukin-1 beta (IL-1 beta) was entirely abolished by pre-incubation with anti-IL-1 beta antiserum from the goat. Fever induced by intravenous (i.v.) injection of IL-1 beta was significantly diminished by i.v. infusion of the antiserum. However, i.v. infusion of the antiserum for 1 h did not affect fever induced by i.v. injection of TNF alpha, when the antiserum infusion began either simultaneously with, or 2 h after, the injection of TNF alpha. Furthermore, intracerebroventricular injection of the anti-serum did not affect TNF alpha-induced fever. The intracerebroventricular administration of naloxone (an opioid receptor antagonist) significantly diminished TNF alpha-induced fever. The results suggest that IL-1, both in the blood circulation and in the brain, may not be involved in TNF alpha-induced fever. Similar to the contribution of eicosanoids, the opioid system in the brain seems somehow to contribute to the mechanism of the development of fever induced by TNF alpha in rabbits.

Suppressive effect of intravenous immunoglobulins on the activity of interleukin-1.

In order to study the effect of human immunoglobulin preparations for intravenous use (IVIg) on the production and activity of interleukin-1 (IL-1) derived from monocytes, we treated cultured monocytes with IVIg and examined the lymphocyte-activating factor (LAF) activity of IL-1 in the culture supernatants. The results showed that IVIg suppressed the activity from most healthy adults and some febrile children with acute respiratory disease or Kawasaki disease. Further studies revealed that intact Ig (whole molecular Ig) did not suppress the mRNA expression of IL-1 alpha or IL-1 beta in mononuclear cells, that intact Ig and pepsin-digested Ig inhibited the LAF activity of recombinant IL-1 (rIL-1) and also that intact Ig contains immunoglobulin (probably anti-IL-1 antibody) which binds with rIL-1 by dot blotting using biotin-streptavidin. These results suggest that IVIg suppresses neither IL-1 synthesis nor the release of IL-1 from monocytes but does neutralize IL-1 alpha and IL-1 beta activity by binding IL-1 proteins as an anti-IL-1 antibody.

Di- n-pentyl phthalate-induced inflammatory changes in the rat testis are accompanied by local production of a novel lymphocyte activating factor

Phthalate esters (PAE) are plasticizers in polyvinyl chloride plastics used, for example, in package material for medical solutions. PAE exposure is associated with testicular damage that primarily affects Sertoli cells, and is concomitant with leukocyte infiltration into the testicular interstitium. We have demonstrated that the rat testis constitutively produces a lymphocyte activating factor (LAF) resembling interleukin-1α, and originating from Sertoli cells. The testicular interleukin-1-like factor (tIL-1) has a relative molecular mass ( M r) of 17,000 (17 k) and an isoelectric point (p I) of 5.7. In the present study we have measured testicular LAF activity after exposure to di- n-pentyl phthalate (DPP) in 40-day-old rats. We found a large increase in LAF bioactivity which was evident already 3 h after a single oral dose of DPP. The increase was maximal 9–12 h after exposure, and had decreased toward the control level at 24 h. The increased activity was found to be at least partly due to the induction of a novel LAF with M r 38,000 and p I 4.5. Morphological examination confirmed earlier results with an interstitial leukocyte infiltration 6 h after DPP exposure. The identity of the novel LAF and its functional relation to testicular inflammation remain to be established.

Evidence for an active hydrophobic form of factor H that is able to induce secretion of interleukin 1‐β or by human monocytes

We studied the capacity of human factor H to promote the secretion of a lymphocyte-activating factor (LAF) by human monocytes cultured under serum-free conditions. Presence of LAF in the culture supernatants was assessed with the mouse thymocyte assay. Highly purified factor H alone had no effect on thymocyte proliferation. When monocytes were cultured with factor H for 24 h, a significant secretion of LAF was observed. The effect was dose dependent over a range of factor H concentrations from 1 to 15 micrograms/ml. Polymyxin B did not abrogate the capacity of factor H to induce LAF secretion. Adsorption of factor H preparations onto anti-factor H-Sepharose completely suppressed the phenomenon. Conversely, the activity was recovered in the acidic eluate. Furthermore, factor H subpopulation phi 2, that was able to bind to phenyl-Sepharose, was a stronger inducer of LAF secretion by monocytes than the subpopulation phi 1 (which did not bind to phenyl-Sepharose). Using a specific radioimmunoassay for interleukin 1-beta (IL 1 beta), we observed a good correlation between the LAF activity and the amount of IL 1 beta secreted by human monocytes stimulated with factor H. We have shown previously that factor H (phi 2) bound specifically on Raji cells whereas factor H (phi 1) did not. These results argue for the participation of the interaction of factor H with its receptor to stimulate the secretion of IL 1 by monocytes and that the phi 2 form of factor H is a ligand for the human factor H receptor.

In vivo inhibition of tumor growth of B16 melanoma by recombinant interleukin 1β: I. Tumor inhibition parallels lymphocyte-activating factor activity of interleukin 1β proteins

Seven daily intratumoral injections of human recombinant interleukin 1β (rHu-IL 1β) inhibit the growth of B16 melanoma in syngeneic female C57BL 6 mice. Inhibition was dose dependent and ranged from 36% to 93%. Other routes of injection of rHu-IL 1β (intramuscular, intraperitoneal, intradermal) inhibited tumor growth but to a lesser degree (27% to 50%). Two different rIL 1βs, one a mutein of rHu-IL 1β (Glu-4) and the other one murine IL 1β (rM-IL 1β), were tested in the tumor inhibition model. rM-IL 1β inhibited tumor growth at lower concentrations than did rHu-IL 1β and also had enhanced IL 1 activity in the thymocyte assay in vitro. The mutein of rHu-IL 1β (Glu-4) had significantly reduced in vitro IL1 activity and did not inhibit tumor growth. No cytotoxic or cytostatic effects of rHu-IL 1β were observed in in vitro assays. These results suggest that rHu-IL 1β has antitumor activity in vivo that is probably not due to its direct effects on B16 cells but rather is mediated by secondary effects of IL 1β.

Lymphocyte activating factor activity in the serum and cerebrospinal fluid of patients with multiple sclerosis

Serum and cerebrospinal fluid (CSF) from patients with multiple sclerosis (MS), patients with other (non-inflammatory) neurological diseases (OND), patients with non-inflammatory non-neurological diseases, and normal controls were assayed for lymphocyte activating factor (LAF) activity by thymocyte costimulation. LAF activity was detected in normal control sera, which did not differ significantly in this respect from MS or OND patient sera. Not were there significant differences by stage of MS (chronic progressive MS, MS in relapse and MS in remission) or between MS patients and the non-inflammatory non-neurological controls. Almost all the CFSs assayed presented lower values than did the corresponding sera. Serum and CSF after fractionation showed no significant increase in LAF activity except in the 2 MS patients in remission. From these data it may be assumed that LAF activity does not necessarily correspond to the clinical phase of MS. The possible role of LAF activity as a marker of MS progression has yet to be determined.

Possible involvement of lymphocyte activating factor(LAF) as an endogenous pyrogen in fever induced by the cell wall skeleton of Nocardia rubra(N-CWS).

We investigated whether interleukin-1 (IL-1) acts as an endogenous pyrogen (EP) on the fever caused by the cell wall skeleton of Nocardia rubra (N-CWS) in guinea pigs. IL-1 activity was expressed as potency of lymphocyte activating factor (LAF). When guinea pig peritoneal macrophages were pulse-stimulated with N-CWS (1-100 micrograms/ml), dose-dependent LAF activity was detected in the supernatants after culture for 4 h. Gel filtration of the culture supernatants on Sephadex G-200 showed that the fractions with LAF activity were not the same as those with cytotoxic activity for L-929 cells, which was measured as an index of tumor necrosis factor (TNF) in parallel with LAF activity. Pyretic activity was detected both in the fractions with LAF activity and in those with cytotoxic activity for L-929 cells. Furthermore, when these macrophages were pulse-stimulated again, this time with the supernatant obtained from macrophages previously pulse-stimulated with N-CWS, LAF and cytotoxic activity for L-929 cells continued to be released from the macrophages. We suggest that IL-1 might be a possible EP in the process of fever elicited by N-CWS, and that such an EP stimulates the macrophages to release further IL-1 or TNF. The resultant long-lasting fever would thus be caused by the continuous release of an EP.

Lipopolysaccharide interactions with lysozyme differentially affect lipopolysaccharide immunostimulatory activity.

The effect of complex formation between lysozyme and lipopolysaccharide (LPS) on the immunostimulatory activities of LPS have been investigated in vitro. Three prototype immunostimulatory activities were examined: B-lymphocyte proliferation, B-lymphocyte differentiation and macrophage production of lymphocyte-activating factor activity. Different effects of lysozyme were noted, depending upon the structure of the LPS, even though previous studies have established that all LPS preparations readily bind lysozyme. Both Re-LPS- and lipid-A-dependent immunostimulatory activities were readily inhibited by lysozyme in a dose-dependent fashion. In contrast, S-LPS and Ra-LPS were unaffected in their immunostimulatory activities by lysozyme. These differences were not the result of quantitative differences in LPS binding of lysozyme, or effects of lysozyme on overall binding of LPS to target cells. These data suggest that the factors which dictate the initial interactions between LPS and lymphoreticular cells may not be identical for all LPS preparations and/or purified lipid A.

Interleukin-1-like activity in the exudate of air-pouch inflammation in rats, and its participation in granuloma formation.

The in vivo production of lymphocyte activating factor (LAF) activity was investigated in the exudate of the rat air-pouch inflammation model. An inflammatory reaction was induced by lipopolysaccharide (LPS) injection into the air-pouch, and the time course of LAF activity in the exudate was investigated. LAF activity in the exudate reached a peak by 6 h, and rapidly decreased at 10 to 48 h after the LPS injection. Dexamethasone revealed strong inhibitory action on LAF activity and granuloma formation. On the other hand, indomethacin could not inhibit either of the phenomena. In conclusion, LAF (IL-1) is rapidly produced after the onset of inflammation and may participate in the subsequent granuloma formation.

Lymphocyte activating factor (LAF) and the acute-phase response in adjuvant arthritic rats

The purpose of the study was to determine the temporal relationship between lymphocyte activating factor (LAF) activity and the acute-phase response, as measured by plasma fibronectin (Fn), C-reactive protein (CRP), and albumin levels in adjuvant arthritic rats. LAF activity as measured in the thymocyte costimulator assay, and plasma Fn, CRP, and albumin levels were measured during the acute (Day 3), intermediate (Day 10), and systemic (Day 17) phases of arthritic disease. On Day 3, supernatants from whole spleen cells of adjuvant-injected rats did not exhibit abnormal LAF activity. By Day 10, LAF activity in splenic supernatants from arthritics was significantly ( P ⩽ 0.05) higher than normal, although the increase was no greater than 60%. On Day 17 the LAF activity from arthritic rats had increased an average 300% compared to normals. In contrast to the time course of IL-1 activity, Fn and CRP levels in the arthritic rat were significantly higher than normal at all three time points, although there was a transient fall in Fn and CRP concentrations on Day 10. Plasma albumin levels in arthritic rats were subnormal ( P ⩽ 0.01) on Days 3, 10, and 17, although the concentration of plasma albumin on Day 10 was significantly higher than that measured on Day 3. The acute, intermediate, and systemic phases of adjuvant arthritic paw inflammation paralleled the abnormal profile of Fn, CRP, and albumin concentrations over time. However, LAF activity from arthritic rat spleen cells increased gradually and more closely coincided with the systemic appearance of the disease. Since the appearance of abnormal plasma protein levels in arthritic rats preceded the appearance of increased splenic LAF activity, it appears that there is no causal relationship between enhanced splenic LAF activity and early alteration of plasma Fn, CRP, and albumin levels.

Increased spontaneous production of interleukin-1 together with inhibitory activity in systemic sclerosis.

1. Increased spontaneous production of interleukin-1, measured as lymphocyte-activating factor activity, was seen in unstimulated monocytes from systemic sclerosis patients. 2. Inhibitory activity to interleukin-1 was seen in both normal and patient monocyte supernatants. 3. Inhibitory activity was significantly higher in unstimulated and stimulated monocyte supernatants from systemic sclerosis patients. 4. The net effect was an apparent decrease in lymphocyte-activating factor activity in the monocyte supernatants from systemic sclerosis patients. 5. These findings suggest a possible mechanism by which collagen deposition could be enhanced, thereby giving rise to the extensive fibrosis characteristic of systemic sclerosis.

Alteration of interleukin-1 activity and the acute phase response in adjuvant arthritic rats treated with disease modifying antirheumatic drugs

Interleukin-1 (IL-1) activity and the acute phase response, as measured by plasma CRP and iron, were used to determine if the standard disease modifying antirheumatic drugs (DMARDs), gold, chloroquine and D-penicillamine had a common profile of activity in the adjuvant arthritic (AA) rat. All drugs were tested at a dose which significantly reduced noninjected paw swelling in AA rats. Inhibition of paw edema ranged from 37% for D-penicillamine (100 mg/kg) to 69% for auranofin (10 mg/kg). Two week medication of AA rats with gold sodium thiomalate (GST, 10 mg/kg, i.m.) or auranofin (10 mg/kg, p.o.) resulted in a significant decrease in splenic IL-1 activity, as measured in the standard lymphocyte activating factor (LAF) assay. The acute phase response, often associated with elevated IL-1 activity, was also significantly reduced following treatment of AA rats with 10 mg/kg of GST or auranofin (oral gold). Inhibition of the acute phase response by gold was determined by a significant reduction of plasma CRP levels (56-71% reduction) and enhancement of plasma iron levels (27-52% enhancement). In contrast to the effect of GST and auranofin on IL-1, CRP and iron, treatment with chloroquine (20, 30 and 35 mg/kg) and D-penicillamine (55 and 100 mg/kg) failed to reduce the acute phase response (as measured by plasma CRP and iron) or alter LAF activity from AA rat spleen cell supernatants. Based on its ability to reduce LAF activity in spleen cell supernatants and reduce the acute phase response, it is possible that the activity of gold in the AA rat may in part be due to its ability to inhibit IL-1 production in vivo. The inability of chloroquine and D-penicillamine to alter LAF activity and the acute phase response in AA rats does not preclude their possession of an immunoregulatory mechanism of action, but it does indicate that their mechanism of action in the AA rat probably differs from that of GST and auranofin.

Endotoxin-associated protein: interleukin-1-like activity on serum amyloid A synthesis and T-lymphocyte activation.

Bacterial endotoxins or lipopolysaccharides (LPS) elicit a variety of biologic activities in intact animals and various in vitro systems. LPS from most gram-negative bacteria have appeared to have similar biologic activities regardless of the species of origin or method of preparation of the LPS. More recent studies have suggested differences in the effects of protein-rich as opposed to protein-free LPS in inducing mitogenesis of lymphocytes from endotoxin-resistant C3H/HeJ mice. These studies examine other activities of endotoxin-associated protein (EAP), purified to less than 0.007% contamination with LPS, and demonstrate that this material has activity mimicking some of the effects of interleukin-1 (IL-1). EAP proved to be as potent as LPS in eliciting rises in concentrations of serum amyloid A (SAA) and was active in both endotoxin-sensitive (CF1) and endotoxin-resistant (C3H/HeJ) mice. In contrast to LPS, which mediates its SAA-inducing activity by release of an inducer (IL-1) from LPS-stimulated macrophages, EAP appeared to act directly to induce SAA production, in that incubation with macrophages failed to increase its activity. EAP also exhibited IL-1-like activity in the lymphocyte-activating factor assay when both CF1 and C3H/HeJ thymocytes and macrophages were tested. The lymphocyte-activating factor activity of EAP was not blocked by addition of polymyxin B. In addition, EAP exerted stimulatory activity on resting human T lymphocytes, costimulated with Sepharose-bound anti-CD3 monoclonal antibody 64.1, comparable to that observed with purified human monocyte IL-1. These studies indicate that proteins from procaryotic cells may act as cytokines for some eucaryotic cells.

Separation and comparison of two monokines with lymphocyte-activating factor activity: IL-1 beta and hybridoma growth factor (HGF). Identification of leukocyte-derived HGF as IL-6.

Supernatants of mitogen-stimulated human leukocytes contain two biologically related cytokines, IL-1 and hybridoma growth factor (HGF). IL-1 beta is a potent inducer of HGF in fibroblasts but has little stimulating effect on monocytes that spontaneously produce HGF. Leukocyte-derived HGF and IL-1 were separated by the use of affinity chromatography on specific antibodies and discriminating assay systems for both cytokines. They had different Mr upon gel filtration and SDS-PAGE. In contrast to IL-1 beta, HGF showed heterogeneity on a cation-exchange column. IL-1 beta and HGF were purified to homogeneity by a sequence of four and five purification steps, respectively. Leukocyte-derived HGF was characterized by analysis of its NH2-terminal amino acid sequence. This revealed complete homology with fibroblast-derived HGF, 26-kDa protein, IFN-beta 2, and B cell stimulatory factor 2, molecules which have collectively been designated as IL-6. IL-1 beta exerted an antiviral and growth-promoting effect of fibroblasts, whereas HGF/IL-6 did not. Both IL-1 and IL-6 possessed lymphocyte-activating factor activity, which could be neutralized only by an anti-serum against the corresponding cytokine.

Alteration of interleukin-1 production and the acute phase response following medication of adjuvant arthritic rats with cyclosporin-A or methotrexate

The purpose of the paper was to determine whether two clinically active antirheumatic compounds, cyclosporin-A (CS-A) and methotrexate (MTX) were efficacious in the treatment of adjuvant arthritis (AA) in rats, as measured by reduction of paw inflammation, lymphocyte activating factor (LAF) activity and the acute phase response. Parameters of the acute phase response consisted of plasma fibronectin (Fn), C-reactive protein (CRP), albumin and iron. Rats injected with Freund's complete adjuvant on day 1, developed systemic arthritis, which was quantitated by measuring non-injected paw swelling on day 17. When compared to normal animals, AA rats had significantly ( P⩽0.01) increased: (1) splenic LAF activity (100% increase), (2) plasma Fn (58%), and (3) CRP (122%), as well as abnormally reduced levels of: (1) plasma albumin (53% reduction), and (2) iron (54%). Orally dosing AA rats from days 3 to 17 with the immunoregulatory drugs, CS-A (3 and 5 mg/kg) or MTX (0.5 and 1 mg/kg), significantly ( P⩽0.01) reduced paw inflammation (100% reduction), increased final body wt 40 – 50 g over arthritic controls and decreased LAF activity from splenic leukocytes. The acute phase response, often associated with a high degree of LAF activity, was significantly ( P⩽0.01) decreased by dosing with CS-A (3 and 5 mg/kg) and MTX (0.5 and 1 mg/kg). The inhibition of the acute phase response was measured by reduction of high plasma Fn levels (42 – 79% decrease) and CRP levels (57 – 100% decrease) as well as elevation of subnormal levels of plasma albumin (57 – 101% increase) and iron (40 – 114% increase). Dosing with the nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin (50 and 100 mg/kg) or phenylbutazone (10 and 30 mg/kg), significantly inhibited paw inflammation (29 – 85%), but did not decrease the high rate of splenic LAF activity, nor did aspirin (55, 100 and 200 mg/kg) or phenylbutazone (1, 10 and 30 mg/kg) alter the acute phase response in AA rats, as measured by levels of plasma Fn, CRP, albumin and iron. Since CS-A and MTX have been reported to be effective in the treatment of RA, their activity in the LAF, Fn, CRP, albumin and iron assays of the AA rat suggests that these immunological and serological parameters may be useful in identifying potential antirheumatic drugs and distinguishing them from standard NSAIDs.

Modulation of lymphocyte activating factor activity (interleukin 1 like activity) and acute phase proteins in pertussis-induced air pouch inflammation by muramyl dipeptide.

We have studied the effect of the macrophage activator, muramyl dipeptide (MDP) on immune inflammation induced in the rat six day subcutaneous air pouch. Treated animals received either 100 micrograms or 200 micrograms MDP at the time of challenge and twenty four hours before exudate harvest. Using the thymocyte co-mitogenic assay for lymphocyte activating factor (LAF), 100 micrograms MDP enhanced LAF activity whereas 200 micrograms caused inhibition. Increased dilution of 200 micrograms exudate in this assay removed this inhibition. Similarly, at the lower dose, MDP caused enhanced production of the acute phase protein alpha 1 glycoprotein, whereas the higher dose had no effect. The present study suggests that macrophage activity can be manipulated in vivo to produce LAF and naturally occurring inhibitors of LAF. These studies indicate that the stimulation of LAF inhibitors by MDP may be a potential therapeutic action.

Macrophage-Mediated Modulation of Hepatocyte Protein Synthesis

We have previously reported an in vitro model demonstrating decreased hepatocyte protein synthesis following co-culture with macrophage-rich peritoneal cells (MRPC) in Sprague-Dawley rats. These observations have been proposed by us and others to represent a possible model for macrophage- or Kupffer cell-mediated modulation of hepatocyte function. Such a mechanism may play a role in the etiology of hepatic failure in sepsis. This effect is shown in this investigation to be completely blocked by dexamethasone at concentrations equal to or greater than 10(-9) M. The presence of lymphocyte-activating factor in the MRPC-conditioned medium is suppressed at the same concentration of dexamethasone. Resident MRPC were shown to secrete significant amounts of lymphocyte-activating factor activity without further in vitro activation. These results support the concept that the MRPC mediation of decreased hepatocyte protein synthesis is inflammatory in nature and possibly associated with macrophage activation.

Mononuclear cell-mediated modulation of synovial cell metabolism: I. Collagen synthesis

Human PHA-stimulated mononuclear cells produce a factor which inhibits synovial cell collagen and non-collagen protein synthesis, whereas it enhances hyaluronic acid (HA) production. Indomethacin (10 −4–10 −6 M), a cyclo-oxygenase inhibitor, suppresses this effect, suggesting that the mechanism is prostaglandin-mediated. The active material, of apparent molecular weight 12000–20000, also displays the properties of the mononuclear cell factor (MCF) previously described by others, since its stimulates collagenase and PGE 2 release by the cultured synovial cells. Furthermore, it co-purifies with interleukin 1 (IL 1) as shown by lymphocyte-activating factor activity. This strongly suggests that IL 1 could be responsible for some (or all) the effects observed on MCF-exposed synovial cells. From these data, we deduce the possibility that mononuclear cells may participate in limiting synovial collagen deposition in rheumatoid arthritis.