Biomedical subjects

N van Rooijen

Publications and source records attributed to N van Rooijen.

At least 37 records · Page 2Linked to original sources

PubMed2000

Treatment with liposome-encapsulated clodronate as a new strategic approach in the management of immune thrombocytopenic purpura in a mouse model.

Immune thrombocytopenic purpura (ITP) is an autoimmune disease related to the presence of elevated levels of platelet-associated immunoglobulin, or autoantibodies. In recent years the importance of macrophage Fc gamma receptors in the uptake of platelets in ITP has been confirmed. Although in patients with ITP the platelet destruction occurs in liver and spleen, in this present experimental mouse model the liver was the principal organ of sequestration of sensitized platelets. The uptake in the spleen, bone marrow, lung, and kidneys was negligible and not different from that in control animals. In addition, the trapped platelets did not return to circulation, and new cells derived from the platelet-storage pool or new thrombocytogenesis were necessary to restore the platelet count. The depletion of splenic and hepatic murine macrophages by liposome-encapsulated clodronate (lip-clod) was studied as a new strategy for ITP treatment. Lip-clod inhibits, in a dose-dependent manner, the antibody-induced thrombocytopenia. Moreover, lip-clod treatment rapidly restored (24 hours) the platelet count in thrombocytopenic animals to hematologic safe values, and despite additional antiplatelet antiserum treatment, mice were able to maintain this level of platelets at least up to 48 hours. The bleeding times in lip-clod-treated animals was not different from those in controls, demonstrating that the hemostasis was well controlled in these animals. The results presented in this study demonstrate that lip-clod treatment can be effective in the management of experimental ITP. (Blood. 2000;96:2834-2840)

Animals↗

PubMed2000

Cutting edge: contribution of NK cells to the homing of thymic CD4+NKT cells to the liver.

In contrast to peripheral lymphoid organs, in the liver a high proportion of T cells are CD4+NKT cells. We have previously reported that LFA-1 plays a pivotal role in the homing of thymic CD4+NKT cells to the liver. In the present study, we further assessed which cell type participates in the homing of thymic CD4+NKT cells to the liver. The accumulation of donor thymocyte-derived CD4+NKT cells in the liver of SCID mice that had been reconstituted with thymocytes from C57BL/6 mice was severely impaired by in vivo depletion of NK cells, but not Kupffer cells in recipients. These results suggest that NK cells participate in the homing of thymic CD4+NKT cells to the liver. We assume that LFA-1 expressed on NK cells is involved in this mechanism.

Animals↗

PubMed2000

Dual role for macrophages in vivo in pathogenesis and control of murine Salmonella enterica var. Typhimurium infections.

Salmonella spp. are regarded as facultative intracellular bacterial pathogens which are found inside macrophages (Mphi) after i. v. infection. It is generally assumed that Mphi restrict the replication of the bacteria during infection. In this study we examined the in vivo activities of Mphi during experimental S. typhimurium infections, using a selective liposome-based Mphi elimination technique. Unexpectedly, elimination of Mphi prior to infection with virulent S. typhimurium decreased morbidity and mortality, suggesting that Mphi mediate the pathology caused by S. typhimurium. Removal of Mphi) during vaccination with attenuated S. typhimurium did not affect protection against challenge with virulent S. typhimurium, suggesting that Mphi are not required for the induction of protective immunity and that other cells must function as antigen-presenting cell to elicit T cell-mediated protection. However, Mphi appeared to be important effectors of protection against challenge infection since elimination of Mphi from vaccinated mice prior to challenge infection with virulent S. typhimurium significantly decreased protection. These results enhance our understanding of the control of S. typhimurium growth in vivo, and moreover suggest that Mphi play a major role in the pathology of virulent S. typhimurium infections. As such, these cells may present a novel target for therapeutic intervention.

Animals↗

PubMed2000

Synovial macrophage depletion with clodronate-containing liposomes in rheumatoid arthritis.

OBJECTIVE: To assess whether intraarticular (IA) administration of clodronate liposomes results in local macrophage depletion in patients with rheumatoid arthritis (RA). Primary goals were to address both the immunohistologic and potential toxic effects of this approach. Moreover, the correlation between immunohistologic findings and clinical assessments of disease activity and cartilage damage were assessed. METHODS: An open study was conducted in consecutive RA patients who were scheduled for knee joint replacement in our department. Synovial biopsy tissue was obtained from the knee joint at 2 weeks before and at the time of surgery. This protocol was controlled for safety and immunohistologic concordance in 6 patients. One week before surgery, 10 patients received a single IA dose of clodronate liposomes. Staining of synovial tissue for cell markers (CD68, CD14, CD3, CD38) and adhesion molecules (vascular cell adhesion molecule 1 [VCAM-1], intercellular adhesion molecule 1 [ICAM-1]) was assessed by 2 blinded observers. Local and systemic parameters of disease activity were measured before each intervention. Cartilage damage was scored using standard radiologic techniques at baseline and during surgery. RESULTS: A single IA dose of clodronate liposomes significantly reduced the number of CD68-positive cells (P = 0.005) and the expression of ICAM-1 and VCAM-1 in the synovial lining (P = 0.013 and P = 0.039, respectively). The intervention did not affect fibroblast-like synoviocytes, T cells, or plasma cells. No immunohistologic changes were observed in the control group. The procedure was well tolerated. The levels of ICAM-1 and VCAM-1 in the sublining layers correlated with the extent of macroscopic synovitis (P < 0.0005 and P < 0.005, respectively). The expression of ICAM-1 and CD14 in the sublining correlated with the levels of C-reactive protein (P < 0.0005 and P < 0.01, respectively). Cartilage destruction was correlated only with the expression of CD68 in the sublining (P = 0.02). CONCLUSION: A single IA administration of clodronate liposomes leads to macrophage depletion and decreased expression of adhesion molecules in the synovial lining in patients with longstanding RA. The procedure is well tolerated, and its therapeutic potential is currently under investigation. The expression of adhesion molecules in the sublining layers reflects ongoing inflammation.

Adult↗

PubMed2000

Negligible role for NK cells and macrophages in delayed xenograft rejection.

Hyperacute rejection (HAR) of a discordant xenograft can be avoided by complement manipulation, but delayed xenograft rejection (DXR) still leads to graft loss. It is generally assumed that macrophages and NK cells play key roles in DXR. In the present study the survival times and cellular infiltrate following guinea pig to rat heart transplantation was analyzed in the course of DXR, following aspecific and specific manipulation of macrophages and NK cells. HAR was overcome by a single injection of cobra venom factor 1 day before heart transplantation. To aspecifically reduce the inflammatory response dominating DXR, dexamethasone (DEXA) was given. Treatment with DEXA markedly reduced infiltration by NK cells, macrophages, and granulocytes. It also led to prolonged graft survival times (median survival of 0.4 days, n = 10, P < 0.05). In the second series of experiments the specific roles of NK cells and macrophages in DXR were further assessed. Monoclonal antibody 3.2.3 was used to selectively deplete NK cells. Liposome-encapsulated dichloromethylene biphosphonate was given to achieve macrophage depletion. Neither of these specific treatments, alone or combined, led to prolonged graft survival. Immunohistology revealed that at day 2 after transplantation no NK cells or macrophages were present in grafts from the combined treatment group. Only a mild infiltration of granulocytes was observed. Collectively, these results strongly suggest that NK cells and macrophages are not likely to be pivotal cell types in DXR.

Animals↗

PubMed2000

Distinctive roles of neutrophils and monocytes in anti-thy-1 nephritis.

Anti-Thy-1.1 glomerulonephritis as an experimental model for mesangial proliferative glomerulonephritis was induced in Wistar rats by a single injection of monoclonal IgG2a-anti-Thy-1.1 antibody (ER4G). This transient model is complement-mediated and leads to mesangial-cell (MC) lysis followed by MC proliferation, glomerular microaneurysm formation, glomerular influx of polymorphonuclear leukocytes (PMNs) and macrophages, proteinuria, and hematuria. In this study we investigated the distinctive roles of infiltrating PMNs or monocytes/macrophages by treating rats with an antibody against rat integrin CD11b/CD18 (ED7) or by depletion of monocytes with multilamellar clodronate liposomes, respectively. ED7 administration resulted in reduction of the influx of PMNs in glomeruli during the first 6 days after induction of Thy-1.1 nephritis, whereas treatment with an isotype-matched irrelevant antibody (PEN9) or with phosphate-buffered saline had no effect on macrophage influx. Increased glomerular C3 and C6 deposition on days 1 and 3 was seen in the ED7-treated rats but not seen in the control groups. In addition, the ED7-treated group showed an increased number of aneurysmatic glomeruli and more severe hematuria. Monocyte/macrophage depletion led to a significant reduction of mesangial matrix expansion, although mesangial proliferation, proteinuria, and hematuria remained unaltered. These results, together with the known effects of PMN-derived enzymes on C3 cleavage, suggest that a reduction in the influx of PMNs results in sparing of C3 and consequently of more complement activation in the glomerulus with increased complement-mediated damage. Our data indicate that infiltrating PMNs and monocytes/macrophages play distinctive roles during inflammation in this model of MC glomerulonephritis.

Animals↗

PubMed2000

Importance of Kupffer cells for T-cell-dependent liver injury in mice.

T cells seem to be responsible for liver damage in any type of acute hepatitis. Nevertheless, the importance of Kupffer cells (KCs) for T-cell-dependent liver failure is unclear. Here we focus on the role of KCs and tumor necrosis factor (TNF) production after T cell stimulation in mice. T-cell- and TNF-dependent liver injury were induced either by Pseudomonas exotoxin A (PEA), by concanavalin A (Con A), or by the combination of subtoxic doses of PEA and the superantigen Staphylococcus enterotoxin B (SEB). KCs were depleted by clodronate liposomes. Although livers of PEA-treated mice contained foci of confluent necrosis and numerous apoptotic cells, hardly any apoptotic cells were observed in the livers of Con A-treated mice. Instead, large bridging necroses were visible. Elimination of KCs protected mice from PEA-, Con A-, or PEA/SEB-induced liver injury. In the absence of KCs, liver damage was restricted to a few small necrotic areas. KCs were the main source of TNF. Hepatic TNF mRNA and protein production were strongly attenuated because of KC-depletion whereas plasma TNF levels were unaltered. Our results suggest that KCs play an important role in T cell activation-induced liver injury by contributing TNF. Plasma TNF levels are poor diagnostic markers for the severity of TNF-dependent liver inflammation.

ADP Ribose Transferases↗

PubMed2000

Endotoxin-induced aggravation of preservation-reperfusion injury of rat liver and its modulation.

BACKGROUND/AIMS: In clinical transplantation, exposure of donors to gut-derived endotoxin occurs frequently and may adversely affect liver transplantation therapy. The aim of this study was to investigate: 1) whether brief exposure of rats to endotoxin before liver procurement aggravates the early phase of reperfusion injury of hepatic explants; and if so 2) whether Kupffer cell activation is a contributing factor to liver injury; and 3) whether heparin and pentoxifylline could minimize this effect. METHODS: Male Wistar rats were injected with 0.2-4.0 mg/kg of Escherichia coli lipopolysaccharide 2 h prior to liver harvest. After preservation in University of Wisconsin cold-storage solution, the livers were reperfused using a blood-free perfusion model. To inactivate Kupffer cells, some rats were pretreated with gadolinium chloride or liposome-encapsulated dichloromethylene-diphosphonate before lipopolysaccharide administration. The other rats received lipopolysaccharide with heparin or pentoxifylline. RESULTS: In a dose-independent fashion, lipopolysaccharide impaired portal flow during graft reperfusion. In a dose-dependent way, lipopolysaccharide increased lactate dehydrogenase release into the perfusate and decreased bile flow and bromosulfophthalein excretion. Gadolinium chloride, liposomal dichloromethylene-diphosphonate, heparin, and pentoxifylline reduced lactate dehydrogenase release by 34%, 43%, 59%, and 64%, respectively, and improved functional parameters of the liver. A 52-fold increased neutrophil infiltration in the liver sinusoids after lipopolysaccharide exposure was not affected significantly by the drugs studied; however, heparin reduced markedly neutrophil activation. CONCLUSIONS: The results of this investigation provide direct evidence that aggravation of preservation-reperfusion injury of rat liver by endotoxin is mediated by Kupffer cell-dependent mechanism(s) and it can be minimized by heparin and pentoxifylline.

Adenosine↗

PubMed2000

Depletion of macrophages reduces axonal degeneration and hyperalgesia following nerve injury.

Inflammatory mechanisms are believed to play an important role in hyperalgesia resulting from nerve injury. Hyperalgesia following nerve injury is temporally linked with Wallerian degeneration and macrophage recruitment, and is reduced in WLD mice, in which Wallerian degeneration is delayed. We sought more direct evidence that macrophages contribute to hyperalgesia and Wallerian degeneration by depleting macrophages with liposomes loaded with dichloromethylene diphosphonate (clodronate, Cl(2)MDP). Rats were subjected to partial ligation of the sciatic nerve. Intravenous injection of liposome-encapsulated clodronate reduced the number of macrophages in the injured nerve, alleviated thermal hyperalgesia and protected both myelinated and unmyelinated fibres against degeneration. The results confirm the role of circulating monocytes/macrophages in the development of neuropathic hyperalgesia and Wallerian degeneration due to partial nerve injury. Macrophage depletion immediately after nerve injury could have some clinical potential in prevention of neuropathic pain.

Analgesics, Non-Narcotic↗

PubMed2000

Pig islet xenograft rejection is markedly delayed in macrophage-depleted mice: a study in streptozotocin diabetic animals.

The present study aimed to evaluate the effect of depletion of macrophages and/or natural killer (NK) cells on islet xenograft rejection in the pig-to-mouse model. Five microliters (4,000 to 5,000 IEQ, islet equivalents) of adult pig islets were transplanted under the renal capsule of C57BL/6 mice with streptozotocin-induced diabetes. Macrophages were depleted by injection of liposome-encapsulated dichloromethylene diphosphonate (Lip-Cl2MDP) intraperitoneally (i.p.) at a dose of 100 microl/ 10 g body weight (BW) 2 days before transplantation, and 50 microl/10 g BW weekly thereafter. NK cells were depleted by injection of the monoclonal antibody NK 1.1 (anti-NK 1.1 mAb) i.p. at a dose of 100 microg/mouse 1 day before transplantation, and then 25 microg per week thereafter. Islet graft survival was monitored by daily measurements of blood glucose. Graft survival was 8 +/- 1.2 days in untreated controls, 9 +/- 1.0 days with anti-NK 1.1 mAb alone, 22 +/- 4.9 days with Lip-Cl2MDP alone (P<0.01 vs. controls), and 26 +/- 3.8 days with Lip-Cl2MDP plus anti-NK 1.1 mAb (P<0.01 vs. controls). In the last group, two of six animals were killed with functioning grafts 30 days after transplantation. In untreated controls, rejected xenografts were heavily infiltrated by F4/80+ macrophages and CD3+T cells. In Lip-Cl2MDP-treated groups, the number of F4/80+ macrophages was markedly reduced. On the periphery of xenografts, a small number of CD3+T cells were observed. In conclusion, our results suggest that strategies targeting macrophages may facilitate islet xenograft survival. A role for NK cells cannot be excluded, but appears to be of minor importance.

Animals↗

PubMed2000

Kupffer cell depletion by CI2MDP-liposomes alters hepatic cytokine expression and delays liver regeneration after partial hepatectomy.

BACKGROUND: Although Kupffer cells (KCs) are capable of producing important growth-stimulating cytokines, their role in liver regeneration following partial hepatectomy (PH) remains poorly understood. METHODS: In the present study liver regeneration was studied after KC-depletion by intravenous administration of liposome-encapsulated dichloromethylene-diphosphonate (C12MDP), a method known to physically eliminate KCs. Furthermore, splenectomy was performed one week prior to PH to exclude the effect of C12MDP-liposomes on macrophage populations in the spleen. RESULTS: KC-depletion was confirmed in cryostat liver sections stained with the monoclonal antibody ED2, a marker for resident tissue macrophages. Forty-eight hours after PH, the cumulative hepatocyte DNA synthesis, as determined in liver sections by the hepatocyte bromodeoxyuridine labeling index, was significantly decreased in KC-depleted rats when compared to control-rats. The weight of the remnant liver, expressed as a percentage of the initial liver weight, was significantly less at 96 h after PH in KC-depleted rats. KC-depletion abolished the hepatic interleukin-6 (IL-6) and interleukin-10 (IL-10) mRNA synthesis and decreased hepatic expression of tumor necrosis factor-alpha (TNF-alpha), hepatocyte growth factor (HGF) and transforming growth factor-beta1(TGF-beta1) mRNA after PH, as was assessed by reverse-transcriptase polymerase chain reaction (RT-PCR). Moreover, at 4 h after PH the systemic release of IL-6 was significantly decreased in KC-depleted rats. CONCLUSION: We conclude that KCs are important for hepatocyte regeneration after PH. Delayed liver regeneration in KC-depleted rats can be explained, at least in part, by an imbalanced hepatic cytokine expression, thereby suppressing important growth-stimulating cytokines.

Animals↗

PubMed2000

A critical role for alveolar macrophages in elicitation of pulmonary immune fibrosis.

Hapten immune pulmonary interstitial fibrosis (HIPIF) is induced by a recall cell-mediated immune response against the hapten 2,4, 6-trinitrobenzene sulphonic acid (TNBS) in the lung. Studies here dissect the role of the cellular components of the bronchoalveolar lavage (BAL) cells (alveolar macrophages [AMs] versus monocytes and immature dendritic cells) in the fibrogenic inflammatory response. BAL cells from HIPIF mice were generally more activated and produced a greater amount of tumour necrosis factor-alpha (TNF-alpha) than controls. Liposome-encapsulated dichloromethylene diphosphonate (Cl(2)MDP) that was inoculated intranasally (i.n.) into mice selectively depleted AMs. Following AM depletion, the number of TNF-alpha-containing cells was reduced, and both the number of immune inflammatory cells recruited into the alveolar space and the subsequent collagen deposition (hydroxyproline) were decreased in the sensitized and intratracheally (i.t.) challenged mice. In conclusion, AMs are required, in part, for the development of pulmonary fibrosis in HIPIF because AM-derived factors such as TNF-alpha are needed for initiation of chemokine and cytokine pathways and accumulation of immune inflammatory cells.

Adoptive Transfer↗

PubMed2000

Antigen processing of vesicular stomatitis virus in situ. Interdigitating dendritic cells present viral antigens independent of marginal dendritic cells but fail to prime CD4(+) and CD8(+) T cells.

Acute macrophage (M phi) depletion, using a liposome-mediated 'suicide technique', markedly suppressed priming of splenic CD4(+) and CD8(+) T-cell responses to vesicular stomatitis virus (VSV). However, phagocytic marginal dendritic cells (MDC), but not interdigitating dendritic cells (IDC), are now known to be also depleted by this technique. To clarify the role splenic dendritic cell (DC) subsets and M phi play in priming for a virus-specific T-cell-mediated immune response, DC and M phi were purified from VSV-infected mice and assayed for the presence of epitopes recognized by VSV helper T (Th) cells and cytotoxic T lymphocytes (CTL). Antigen pulse experiments performed in situ demonstrated that VSV Th cell and CTL epitopes became transiently associated only with DC, but not M phi or B cells, indicating that DC represent the critical antigen-presenting cell (APC) population in vivo for this virus. The failure of MDC/M phi-deficient mice to become primed was not due to the complete elimination of antigen-presenting DC because VSV peptide/class I and II complexes were detected on IDC following lipsome-mediated elimination of phagocytic cells. However, the VSV-induced chemokine response was dramatically suppressed in these mice. Thus, despite the expression of VSV peptide/class I and II complexes, IDC are not sufficient to prime VSV Th cells in the absence of MDC and/or splenic M phi.

Animals↗

PubMed2000

Intrabursal injection of clodronate liposomes causes macrophage depletion and inhibits ovulation in the mouse ovary.

To investigate the role of the ovarian macrophage population in ovulation, we examined the effect of depleting this population using liposome-encapsulated clodronate. Clodronate liposomes, saline liposomes, or saline alone was injected under the ovarian bursa in gonadotropin-primed adult mice, either 84 h (Day -3) or 36 h (Day -1) before ovulation. Ovulation rates were determined by counting the number of oocytes released. The numbers of graafian follicles and corpora lutea were also counted immediately before and after ovulation. Macrophage distribution within the theca and stroma of preovulatory ovaries was examined by immunohistochemistry with specific monoclonal antibodies to the macrophage antigens macrosialin, major histocompatability complex class II (Ia), and F4/80. Injection of clodronate liposomes on Day -1 did not affect ovulation rates, whereas administration on Day -3 caused a significant reduction in ovulation rate (mean oocytes ovulated = 5. 25 +/- 0.6 from clodronate liposome-treated ovaries and 9.13 +/- 0.9 from saline-treated ovaries, respectively, P < 0.05). The numbers of macrosialin-positive macrophages present in the theca at ovulation were reduced by treatment with clodronate liposomes on Day -1, and treatment on Day -3 reduced the numbers of Ia-positive and macrosialin-positive macrophages present in the theca. When the subsequent ovarian cycles were examined by vaginal smearing, the metestrous-2/diestrous stage was found to be extended in clodronate liposome-treated animals (7.5 +/- 1.3 days vs. 3.4 +/- 0.4 days for saline liposome-treated animals, P < 0.05). These results suggest that thecal macrophages may be involved in the regulation of follicular growth and rupture, as well as being important for the normal progression of the estrous cycle.

Analgesics, Non-Narcotic↗

PubMed2000

Inflammation-induced impairment of enteric nerve function in nematode-infected mice is macrophage dependent.

Trichinella spiralis infection in rodents is associated with suppression of ACh release from myenteric plexus that can be mimicked by macrophage-derived cytokines. We verified the presence of a macrophage infiltrate in the intestine during T. spiralis infection and determined the extent to which this cell type is responsible for the neural changes. C57BL/6 mice were infected with 375 T. spiralis larvae by gavage, and the presence of macrophages (F4/80 positive) in the jejunum was determined immunohistochemically. In another experiment, infected mice were treated intravenously with liposomes containing dichloromethylene diphosphonate (clodronate, Cl(2)MDP), which causes apoptosis of macrophages, and killed at postinfection day 6, and jejunal tissues were evaluated for the presence of F4/80-positive cells and for [(3)H]ACh release from the myenteric plexus. Infection caused an infiltration of F4/80-positive cells into the intestinal mucosa, muscle layers, and myenteric plexus region and a significant suppression of ACh release (50%). Depletion of F4/80-positive macrophages using Cl(2)MDP-containing liposomes prevented the suppression in [(3)H]ACh release, identifying macrophages as the cell type involved in the functional impairment of enteric cholinergic nerves.

Acetylcholine↗

PubMed2000

Macrophage-depletion influences the course of murine HSV-1 keratitis.

PURPOSE: Herpes simplex virus type 1 infection of the cornea induces an immune-mediated disease termed "herpes stromal keratitis" (HSK) that is a major cause of blindness. In this study we investigated the influence of macrophage depletion by Cl(2) MDP encapsulated in liposomes (Cl(2) MDP-LIP) on the course of HSV-1 keratitis. METHODS: The corneas of BALB/c mice were infected with 10(5) PFU of HSV-1 (KOS strain). Mice groups received sub-conjunctival PBS or Cl( 2) MDP-LIP injections 7 and 2 days prior to infection. The eyes were studied clinically, histologically and immunohistochemically with F4/80 antibody at various time points after treatment. Clearance of the virus from the HSV-infected eyes was measured with a standard plaque assay. RESULTS: After subconjunctival Cl(2) MDP-LIP treatment, the HSV-1-induced epithelial keratitis was more severe (P < 0.05). The virus titers were significantly higher after macrophage depletion (day 7, P < 0.005). Stromal keratitis developed in 78.6% of HSV-1 infected PBS treated control mice ( n = 14) by day 14 after infection. By subconjunctival Cl(2) MDP-LIP treatment (n = 14) the incidence of stromal keratitis was reduced to 42.9%, and the keratitis was less severe (P < 0.05). CONCLUSIONS: The data demonstrate an influence of macrophages on the course of HSV-1 keratitis in mice. Macrophage depletion influence the viral replication in the cornea and the immune-mediated process of HSK.

Animals↗

PubMed2000

Role of macrophages in restricting herpes simplex virus type 1 growth after ocular infection.

PURPOSE: To investigate the role macrophages play in controlling herpes simplex virus (HSV)-1 replication after infection of the murine cornea. METHODS: Macrophage depletion in selected tissues before or after virus infection was achieved by repeated subconjunctival (SCJ) and/or intravenous (IV) injection of liposomes containing dichloromethylene diphosphonate (L-Cl2MDP). Controls received liposomes containing phosphate-buffered saline (L-PBS). The efficiency of depletion was evaluated by histologic examination. Virus content in infected tissues was determined by standard plaque assay. Delayed-type hypersensitivity (DTH) responsiveness was assessed using the ear-swelling assay. Antibody isotype responses to virus antigens and cytokine production were monitored by enzyme-linked immunosorbent assay. RESULTS: Balb/c mice given SCJ injection of L-Cl2MDP 4 and 2 days before HSV-1 corneal infection were found to have ocular virus titers as much as 10(5)-fold higher than that seen in the L-PBS-treated controls 8 days after infection. When L-Cl2MDP treatment was delayed until 2 and 4 days after infection, virus titers in the eye were analogous to those in the control animals. Subconjunctival and submandibular lymph node macrophages in mice given local (SCJ) L-Cl2MDP pretreatment were profoundly reduced, whereas the number of corneal Langerhans' cells and lymph node dendritic cells remained unchanged. Local L-Cl2MDP pretreatment was associated with significantly reduced DTH responsiveness to HSV-1 antigen, and an alteration in selected antibody isotype production. Depletion of macrophages in the subconjunctival tissue before corneal infection was not accompanied by enhanced virus growth at early times (2 or 4 days) after infection. CONCLUSIONS: Macrophages play an important role in restricting HSV-1 growth after corneal infection. These cells appear to be required for the development of an acquired immune response, presumably by functioning in antigen processing and presentation. The hypothesis that macrophages are major participants in innate immunity to HSV-1 corneal infection was not supported.

Acid Phosphatase↗

PubMed2000

Delayed graft rejection in pre-vascularised corneas after subconjunctival injection of clodronate liposomes.

PURPOSE: To test the effects of clodronate liposomes on graft survival and neovascularisation after transplantation in pre-vascularised recipient corneas. METHODS: Corneal neovascularisation was induced in F344 rats by injecting heat inactivated rabbit serum intrastromally. After 4 weeks F344 rats were orthotopically grafted with corneal buttons from DA rats. Directly after transplantation and on 2, 4, 6 and 8 days postoperatively clodronate liposomes were administrated subconjunctivally in one group, whereas the other group remained untreated. For 60 days grafts were observed for signs of graft rejection and neovascularisation. RESULTS: Graft survival was significantly prolonged, but not prevented in clodronate liposome treated rats compared to untreated rats ( p =.004). Also clodronate liposome administration delays growth of corneal neovascularisation after transplantation. CONCLUSIONS: Previous studies revealed that clodronate liposomes prevent corneal graft rejection and reduce neovascularisation in orthotopic corneal allotransplantation in rats. This study shows that also in pre-vascularised recipient corneas subconjunctival administration of clodronate liposomes seems to delay corneal graft rejection and reduces neovascularisation.

Animals↗