Immunization with P10 Peptide Increases Specific Immunity and Protects Immunosuppressed BALB/c Mice Infected with Virulent Yeasts of Paracoccidioides brasiliensis

Paracoccidioidomycosis is a systemic granulomatous disease caused by Paracoccidioides spp. A peptide from the major diagnostic antigen gp43, named P10, induces a T-CD4⁺ helper-1 immune response in mice and protects against intratracheal challenge with virulent P. brasiliensis. Previously, we evaluated the efficacy of the P10 peptide alone or combined with antifungal drugs in mice immunosuppressed and infected with virulent isolate of P. brasiliensis. In the present work, our data suggest that P10 immunization leads to an effective cellular immune response associated with an enhanced T cell proliferative response. P10-stimulated splenocytes increased nitric oxide (NO) production and induced high levels of IFN-γ, IL-1β and IL-12. Furthermore, significantly increased concentrations of pro-inflammatory cytokines were also observed in lung homogenates of immunized mice. P10 immunization was followed by minimal fibrosis in response to infection. Combined with antifungal drugs, P10 immunization most significantly improved survival of anergic infected mice. Administration of either itraconazole or sulfamethoxazole/trimethoprim together with P10 immunization resulted in 100 % survival up to 200 days post-infection, whereas untreated mice died within 80 days. Hence, our data show that P10 immunization promotes a strong specific immune response even in immunocompromised hosts and thus P10 treatment represents a powerful adjuvant therapy to chemotherapy.     

Attempts at a peptide vaccine against paracoccidioidomycosis, adjuvant to chemotherapy

Chemotherapy is the basis of treatment of paracoccidioidomycosis in its various forms. Depending on the Paracoccidioides brasiliensis virulence, the status of host immunity, the degree of tissue involvement and fungal dissemination, treatment can be extended for long periods with an alarming frequency of relapses. Association of chemotherapy with a vaccine to boost the cellular immune response seemed a relevant project not only to reduce the time of treatment but also to prevent relapses and improve the prognosis of anergic cases. The candidate immunogen is the gp43 major diagnostic antigen of P.␣brasiliensis and more specifically its derived peptide P10, carrying the CD4⁺ T-cell epitope. Both gp43 and P10 protected Balb/c mice against intratracheal infections with virulent P. brasiliensis strain. P10 as single peptide or in a multiple-antigen-peptide (MAP) tetravalent construction was protective without adjuvant either by preimmunization and intratracheal challenge or as a therapeutic agent in mice with installed infection. P10 showed additive protective effects in drug-treated mice stimulating a Th-1 type immune response with high IFN-γ and IL-12. P10 and few other peptides in the gp43 were selected by Tepitope algorithm and actually shown to promiscuously bind several prominent HLA-DR molecules suggesting that a peptide vaccine could be devised for a genetically heterogenous population. P10 was protective in animals turned anergic, was effective in a DNA minigene vaccine, and increased the protection by monoclonal antibodies in Balb/c mice. DNA vaccines and peptide vaccines are promising therapeutic tools to be explored in the control of systemic mycoses.     

Effect of macrophage blockade on the resistance of inbred mice toParacoccidioides brasiliensis infection

The effect of macrophage blockade on the natural resistance and on the adaptative immune response of susceptible (B10.D2/oSn) and resistant (A/Sn) mice toParacoccidioides brasiliensis infection was investigated. B10.D2/oSn and A/Sn mice previously injected with colloidal carbon were infected ip with yeast cells to determine the 50% lethal dose, and to evaluate the anatomy and histopathology, macrophage activation, antibody production and DTH reactions. Macrophage blockade rendered both resistant and susceptible mice considerably more susceptible to infection, as evidenced by increased mortality and many disseminated lesions.P. brasiliensis infection and/or carbon treatment increased the ability of macrophages from resistant mice to spread up to 25 days after treatment. In susceptible mice the enhanced spreading capacity induced by carbon treatment was impaired at all assayed periods except at 1 week after infection. Macrophage blockade enhanced DTH reactions in resistant mice, but did not alter these reactions in susceptible mice, which remained anergic. To the contrary, macrophage blockade enhanced specific antibody production by susceptible mice, but did not affect the low levels produced by resistant mice. The effect of macrophage blockade confirms the natural tendency of resistant animals to mount DTH reactions in the course of the disease and the preferential antibody response developed by susceptible mice afterP. brasiliensis infection. On the whole, macrophage functions appear to play a fundamental role in the natural and acquired resistance mechanisms toP. brasiliensis infection.     

Therapeutic DNA vaccine encoding peptide P10 against experimental paracoccidioidomycosis

Paracoccidioidomycosis (PCM), caused by Paracoccidioides brasiliensis, is the most prevalent invasive fungal disease in South America. Systemic mycoses are the 10th most common cause of death among infectious diseases in Brazil and PCM is responsible for more than 50% of deaths due to fungal infections. PCM is typically treated with sulfonamides, amphotericin B or azoles, although complete eradication of the fungus may not occur and relapsing disease is frequently reported. A 15-mer peptide from the major diagnostic antigen gp43, named P10, can induce a strong T-CD4+ helper-1 immune response in mice. The TEPITOPE algorithm and experimental data have confirmed that most HLA-DR molecules can present P10, which suggests that P10 is a candidate antigen for a PCM vaccine. In the current work, the therapeutic efficacy of plasmid immunization with P10 and/or IL-12 inserts was tested in murine models of PCM. When given prior to or after infection with P. brasiliensis virulent Pb 18 isolate, plasmid-vaccination with P10 and/or IL-12 inserts successfully reduced the fungal burden in lungs of infected mice. In fact, intramuscular administration of a combination of plasmids expressing P10 and IL-12 given weekly for one month, followed by single injections every month for 3 months restored normal lung architecture and eradicated the fungus in mice that were infected one month prior to treatment. The data indicate that immunization with these plasmids is a powerful procedure for prevention and treatment of experimental PCM, with the perspective of being also effective in human patients.     

Anergic cells generated by blocking CD28 and CD40 costimulatory pathways in vitro ameliorate collagen induced arthritis

Collagen type II induced arthritis is an experimental model for studying the pathological mechanisms of therapeutic agents for human rheumatoid arthritis. In this study, we have investigated the effects of anergic cells on the development and disease progression of CIA. Anergic cells inhibited the proliferative response to collagen II primed lymphocytes, whereas the supernatant from anergic cell culture had no suppressive effect. Administration of anergic cells reduced the clinical score of CIA and ameliorated the development of CIA. The messenger RNA levels of IL-2 and IFN-γ were significantly decreased, whereas mRNA levels of IL-4, IL-10 and TGF-β showed no significant differences. A decrease in the collagen-specific Th1 associated IgG_2a response was observed, whereas IgG₁ was unaffected. This effective treatment is associated with a reduction in IFN-γ production and through cell-cell contact. Our results suggest that anergic cells may be beneficial for the treatment of rheumatoid arthritis.     

新型硫化氢供体GYY4137对脂多糖诱导的小鼠急性肺损伤的保护作用

目的:急性肺损伤是临床上常见的危重病,发病急,死亡率高,目前仍缺乏有效的治疗手段,新型的外源性硫化氢供体GYY4137具有抗炎、抗休克、抗癌及抗血栓等作用,本研究探讨其对脂多糖诱导的小鼠急性肺损伤的保护作用及其机制。方法:将BALB/c小鼠(18-20 g)随机分为3组:正常对照组(20只),脂多糖组(20只),治疗组(20只),然后复制小鼠脂多糖诱导的急性肺损伤模型:给予小鼠腹腔注射脂多糖(10 mg/kg)复制小鼠急性肺损伤模型模型,治疗组注射脂多糖1小时后给予腹腔注射GYY4137(50 mg/kg),在给予脂多糖8小时后将小鼠处死,留取血清与组织标本。检测小鼠血清中的炎症因子肿瘤坏死因子α、白介素6及白介素10的表达,检测小鼠血清中H2S的含量,测得肺脏湿/干比,检测肺组织中的髓过氧化物酶活性,并测得肺组织中与氧化应激相关的H2O2、·OH与SOD因子的含量。结果:脂多糖引起了严重的肺损伤,GYY4137对脂多糖导致的肺水肿、炎症反应及氧化应激损伤有不同程度的改善,保护了脂多糖造成的肺损伤,降低了脂多糖诱导的小鼠肺脏氧化应激损伤。其保护作用于抗炎、抗氧化有关。结论:GYY4137可能通过抗炎、抗氧化作用途径保护了脂多糖造成的急性肺损伤,可能在炎症疾病模型中也发挥相同作用,并且为未来临床使用缓释硫化氢供体提供了基础资料。     

Multiple CD4+ T cell subsets produce immunomodulatory IL-10 during respiratory syncytial virus infection

The host immune response is believed to contribute to the severity of pulmonary disease induced by acute respiratory syncytial virus (RSV) infection. Because RSV-induced pulmonary disease is associated with immunopathology, we evaluated the role of IL-10 in modulating the RSV-specific immune response. We found that IL-10 protein levels in the lung were increased following acute RSV infection, with maximum production corresponding to the peak of the virus-specific T cell response. The majority of IL-10-producing cells in the lung during acute RSV infection were CD4(+) T cells. The IL-10-producing CD4(+) T cells included Foxp3(+) regulatory T cells, Foxp3(-) CD4(+) T cells that coproduce IFN-γ, and Foxp3(-) CD4(+) T cells that do not coproduce IFN-γ. RSV infection of IL-10-deficient mice resulted in more severe disease, as measured by increased weight loss and airway resistance, as compared with control mice. We also observed an increase in the magnitude of the RSV-induced CD8(+) and CD4(+) T cell response that correlated with increased disease severity in the absence of IL-10 or following IL-10R blockade. Interestingly, IL-10R blockade during acute RSV infection altered CD4(+) T cell subset distribution, resulting in a significant increase in IL-17A-producing CD4(+) T cells and a concomitant decrease in Foxp3(+) regulatory T cells. These results demonstrate that IL-10 plays a critical role in modulating the adaptive immune response to RSV by limiting T-cell-mediated pulmonary inflammation and injury.     

Role of cystic fibrosis transmembrane conductance regulator in pulmonary clearance of Pseudomonas aeruginosa in vivo

Cystic fibrosis (CF)2 is a fatal genetic disease caused by mutations in the CF transmembrane conductance regulator (CFTR) that is commonly associated with chronic pulmonary infections with mucoid Pseudomonas aeruginosa (PA). To test the hypothesis that CFTR plays a direct role in PA adhesion and clearance, we have used mouse lines expressing varying levels of human (h) or mouse (m) CFTR. A subacute intratracheal dose of 3 x 10(6) bacteria was cleared with similar kinetics in control wild-type (WT) and transgenic mice overexpressing hCFTR in the lung from the surfactant protein C (SP-C) promoter (SP-C-hCFTR+/-). In a second series of experiments, the clearance of an acute intratracheal dose of 1.5 x 10(7) PA bacteria was also similar in WT, hemizygous SP-C-hCFTR+/-, and bitransgenic gut-corrected FABP-hCFTR+/+-mCFTR-/-, the latter lacking expression of mCFTR in the lung. However, a small but significant decrease in bacterial killing was observed in lungs of homozygote SP-C-hCFTR+/+ mice. Lung pathology in both WT and SP-C-hCFTR+/+ mice was marked by neutrophilic inflammation and bacterial invasion of perivascular and subepithelial compartments. Bacteria were associated primarily with leukocytes and were not associated with alveolar type II or bronchiolar epithelial cells, the cellular sites of SP-C-hCFTR+/+ transgene expression. The results indicate that there is no direct correlation between levels of CFTR expression and bacterial clearance or association of bacteria with epithelial cells in vivo.     

Role of PAR2 in murine pulmonary pseudomonal infection

Proteinases can influence lung inflammation by various mechanisms, including via cleavage and activation of protease-activated receptors (PAR) such as PAR2. In addition, proteinases such as neutrophil and/or Pseudomonas-derived elastase can disarm PAR2 resulting in loss of PAR2 signaling. Currently, the role of PAR2 in host defense against bacterial infection is not known. Using a murine model of acute Pseudomonas aeruginosa pneumonia, we examined differences in the pulmonary inflammatory response between wild-type and PAR2(-/-) mice. Compared with wild-type mice, PAR2(-/-) mice displayed more severe lung inflammation and injury in response to P. aeruginosa infection as indicated by higher bronchoalveolar lavage fluid neutrophil numbers, protein concentration, and TNF-alpha levels. By contrast, IFN-gamma levels were markedly reduced in PAR2(-/-) compared with wild-type mice. Importantly, clearance of P. aeruginosa was diminished in PAR2(-/-) mice. In vitro testing revealed that PAR2(-/-) neutrophils killed significantly less bacteria than wild-type murine neutrophils. Further, both neutrophils and macrophages from PAR2(-/-) mice displayed significantly reduced phagocytic efficiency compared with wild-type phagocytes. Stimulation of PAR2 on macrophages using a PAR2-activating peptide resulted in enhanced phagocytosis directly implicating PAR2 signaling in the phagocytic process. We conclude that genetic deletion of PAR2 is associated with decreased clearance of P. aeruginosa. Our data suggest that a deficiency in IFN-gamma production and impaired bacterial phagocytosis are two potential mechanisms responsible for this defect.     

Treatment with antileukinate, a CXCR2 chemokine receptor antagonist, protects mice against acute pancreatitis and associated lung injury

Acute pancreatitis is a common, and as yet incurable, clinical condition, the incidence of which has been increasing over recent years. Chemokines are believed to play a key role in the pathogenesis of acute pancreatitis. We have earlier shown that treatment with a neutralizing antibody against CINC, a CXC chemokine, protects rats against acute pancreatitis-associated lung injury. The hexapeptide antileukinate (Ac-RRWWCR-NH2) is a potent inhibitor of binding of CXC chemokines to the receptors (CXCR2). This study aims to evaluate the effect of treatment with antileukinate on acute pancreatitis and the associated lung injury in mice. Acute pancreatitis was induced in adult male Swiss mice by hourly intra-peritoneal injections of caerulein (50 microg/kg/h) for 10 h. Antileukinate (52.63 mg/kg, s.c.) was administered to mice either 30 min before or 1 h after starting caerulein injections. Severity of acute pancreatitis was determined by measuring plasma amylase, pancreatic water content, pancreatic myeloperoxidase (MPO) activity, pancreatic macrophage inflammatory protein-2 (MIP-2) levels and histological examination of sections of pancreas. A rise in lung MPO activity and histological evidence of lung injury in lung sections was used as criteria for pancreatitis-associated lung injury. Treatment with antileukinate protected mice against acute pancreatitis and associated lung injury, showing thereby that anti-chemokine therapy may be of value in this condition.     

Fingerprints of anergic T cells

Peripheral T cell tolerance may result from activation-induced cell death [1], anergy [1], and/or immune response modulation by regulatory T cells [2]. In mice that express a transgenic receptor specific for peptide 111-119 of influenza hemagglutinin presented by E(d) class II MHC molecules as well as hemagglutinin under control of the immunoglobulin-kappa promoter, we have found that anergic T cells [3] can also have immunoregulatory function and secrete IL-10 [4]. In order to obtain information on molecular mechanisms involved in anergy and immunoregulation, we have compared expression levels of 1176 genes in anergic, naive, and recently activated CD4+ T cells of the same specificity by gene array analysis. The results provide a plausible explanation for the anergic phenotype in terms of proliferation, provide new information on the surface phenotype of in vivo-generated anergic CD4+ T cells, and yield clues with regard to new candidate genes that may be responsible for the restricted cytokine production of in vivo-anergized CD4+ T cells. The molecular fingerprints of such T cells should enable the tracking of this small population in the normal organism and the study of their role in immunoregulation.     

Anticachectin/tumor necrosis factor-alpha antibodies attenuate development of cachexia in tumor models

C57BL/6 mice bearing either a transplantable methylcholanthrene-induced sarcoma or Lewis lung adenocarcinoma were passively immunized every other day with a rabbit immunoglobulin fraction raised against murine cachectin/tumor necrosis factor-alpha. Mice bearing methylcholanthrene-induced sarcoma developed tumor-associated hypophagia that was attenuated by anticachectin immunoglobulin treatment. In the same tumor-bearing animals, anticachectin treatment also significantly reduced the extent of carcass protein and fat loss, and reduced tumor weight. Mice bearing Lewis lung adenocarcinoma did not develop significant anorexia or carcass lean tissue depletion as tumor growth progressed, but they lost carcass lipid. Treatment of Lewis lung adenocarcinoma bearing mice with anticachectin antibodies diminished the degree of carcass lipid depletion and prevented plasma hypertriglyceridemia. However, in both tumor models, anticachectin treatment did not affect either the development of anemia, hypoalbuminemia or the increase in serum amyloid P concentrations seen with increasing tumor burden. We conclude that an endogenous cachectin response, inhibitable by exogenously administered antibody, contributes to anorexia and to changes in body fat and protein metabolism in these tumor-bearing animals. Neutralizing endogenous cachectin production with antibodies offers the potential to reduce tissue wasting that is frequently associated with neoplastic disease, but it does not appear to affect all of the hematologic and acute phase responses in these murine tumor models.     

Protective role of reactive oxygen species in endotoxin-induced lung inflammation through modulation of IL-10 expression

Reactive oxygen species (ROS) generated by NADPH oxidase are generally known to be proinflammatory, and it seems to be counterintuitive that ROS play a critical role in regulating the resolution of the inflammatory response. However, we observed that deficiency of the p47(phox) component of NADPH oxidase in macrophages was associated with a paradoxical accentuation of inflammation in a whole animal model of noninfectious sepsis induced by endotoxin. We have confirmed this observation by interrogating four separate in vivo models that use complementary methodology including the use of p47(phox-/-) mice, p47(phox-/-) bone marrow chimera mice, adoptive transfer of macrophages from p47(phox-/-) mice, and an isolated perfused lung edema model that all point to a relationship between excessive acute inflammation and p47(phox) deficiency in macrophages. Mechanistic data indicate that ROS deficiency in both cells and mice results in decreased production of IL-10 in response to treatment with LPS, at least in part, through attenuation of the Akt-GSK3-β signal pathway and that it can be reversed by the administration of rIL-10. Our data support the innovative concept that generation of ROS is essential for counterregulation of acute lung inflammation.     

Lymphocytes from SJL/J mice immunized with spinal cord respond selectively to a peptide of proteolipid protein and transfer relapsing demyelinating experimental autoimmune encephalomyelitis.

Relapsing experimental autoimmune encephalomyelitis (R-EAE) can be induced in SJL/J mice by immunization with spinal cord homogenate and adjuvant. The specific Ag(s) responsible for acute disease and subsequent relapses in this model is unknown. Myelin basic protein (BP), an encephalitogenic peptide of BP (BP 87-99), and proteolipid protein (PLP) can each induce R-EAE in SJL/J mice, and a peptide of PLP (PLP 139-151) has been reported to induce acute EAE. To determine the encephalitogens in cord-immunized mice with R-EAE, the in vitro proliferative responses of lymph node cells (LNC) and central nervous system mononuclear cells to BP, BP peptides, and PLP peptides were examined during acute EAE and during relapses. LNC responded only to PLP peptides 139-151 and 141-151 and did not respond to BP or its peptides during acute or chronic disease. Central nervous system mononuclear cells also preferentially responded to PLP 139-151 and 141-151 during acute and relapsing disease. A PLP 139-151 peptide-specific Th cell line was selected from LNC of cord-immunized donors. Five million peptide-specific line cells transferred severe relapsing demyelinating EAE to naive recipients. We conclude that PLP peptide 139-151 is the major encephalitogen for R-EAE in cord-immunized SJL/J mice. We demonstrate for the first time that Th cells specific for this peptide are sufficient to transfer relapsing demyelinating EAE. The predominance of a PLP immune response rather than a BP response in SJL/J mice suggests that genetic background may determine the predominant myelin Ag response in human demyelinating diseases such as multiple sclerosis.     

A Staphylococcus aureus mouse keratitis topical infection model: cytokine balance in different strains of mice

Staphylococcus is a leading cause of the potentially blinding disease microbial keratitis. Even with the use of antibiotic therapy, the host inflammatory response continues to damage the cornea, which may lead to blindness. Manipulation of the host response may help improve patient outcome from this devastating disease. We aim to understand the contribution of the host response to Staphylococcus aureus infection. A S. aureus keratitis mouse model was developed in both C57BL/6 and BALB/c mice using two different strains of S. aureus (8325-4 and Staph 38). Twenty-four hours postinfection, mice were killed and eyes were harvested for enumeration of bacteria, polymorphonuclear leucocytes, chemokines and cytokines. The laboratory strain 8325-4 was not as virulent as the clinical isolate Staph 38. In vitro data showed a 250-fold increase in invasion of human corneal epithelial cells by Staph 38 compared to 8325-4. BALB/c mice were susceptible to S. aureus infection whereas C57BL/6 mice were resistant. The resistant C57BL/6 mice were polarized towards a Th2 response, which may be protective for these mice. IL-4, IL-10 and IL-6 were elevated significantly in C57BL/6 mice infected with Staph 38 (P < 0.05). Macrophage inflammatory peptide (MIP)-2 was also significantly elevated in C57BL/6 mice (P < 0.001). The susceptible BALB/c mice had a muted cytokine response, which suggests that S. aureus might be 'walled off' during infection and might avoid host defences. IL-4, IL-10 and IL-6 cytokines may be protective during Gram-positive corneal infection and therefore may be useful for adjunct therapies in the treatment of this disease.     

Hypoxia upregulates lung microvascular neurokinin-1 receptor expression

Subacute exposure to moderate hypoxia can promote pulmonary edema formation. The tachykinins, a family of proinflammatory neuropeptides, have been implicated in the pathogenesis of pulmonary edema in some settings, including the pulmonary vascular leak associated with exposure to hypoxia. The effects of hypoxia on tachykinin receptor and peptide expression in the lung, however, remain poorly understood. We hypothesized that subacute exposure to moderate hypoxia increases lung neurokinin-1 (NK-1) receptor expression as well as lung substance P levels. We tested this hypothesis by exposing weanling Sprague-Dawley rats to hypobaric hypoxia (barometric pressure 0.5 atm) for 0, 24, 48, or 72 h. Hypoxia led to time-dependent increases in lung NK-1 receptor mRNA expression and lung NK-1 receptor protein levels at 48 and 72 h of exposure (P < 0.05). Immunohistochemistry and in situ NK-1 receptor labeling with substance P-conjugated fluorescent nanocrystals demonstrated that hypoxia increased NK-1 expression primarily in the pulmonary microvasculature and in alveolar macrophages. Hypoxia also led to increases in lung substance P levels by 48 and 72 h (P < 0.05) but led to a decrease in preprotachykinin mRNA levels (P < 0.05). We conclude that subacute exposure to moderate hypoxia upregulates lung NK-1 receptor expression and lung substance P peptide levels primarily in the lung microvasculature. We speculate that this effect may contribute to the formation of pulmonary edema in the setting of regional or environmental hypoxia.     

A key role of neurokinin 1 receptors in acute pancreatitis and associated lung injury

Earlier studies have shown that mice deficient in NK1 receptors or its ligand, substance P, are protected against acute pancreatitis and associated lung injury. In the current study, the protective effect of NK1 receptor blockage against acute pancreatitis and associated lung injury was investigated, using a specific receptor antagonist, CP-96345. Acute pancreatitis was induced in mice by intraperitoneal (i.p.) injections of caerulein. Substance P levels in plasma, pancreas, and lungs were found to be elevated in a caerulein dose-dependent manner. Mice treated with CP-96345, either prophylactically, or therapeutically, were protected against acute pancreatitis and associated lung injury as evident by attenuation in plasma amylase, pancreatic and pulmonary myeloperoxidase activities, and histological evidence of pancreatic and pulmonary injuries. Pulmonary microvascular permeability was also reduced as a result of CP-96345 treatment. These results point to a key role of NK1 receptors in acute pancreatitis and associated lung injury.     

Amelioration of established experimental autoimmune encephalomyelitis by an MHC anchor-substituted variant of proteolipid protein 139-151

Murine experimental autoimmune encephalomyelitis (EAE) is a CD4+ T cell-mediated autoimmune disorder directed against myelin proteins within the CNS. We propose that variant peptides containing amino acid substitutions at MHC anchor residues will provide a unique means to controlling the polyclonal autoimmune T cell response. In this study, we have identified an MHC variant of proteolipid protein (PLP) 139-151 (145D) that renders PLP(139-151)-specific T cell lines anergic in vitro, as defined by a significant reduction in proliferation and IL-2 production following challenge with wild-type peptide. In vivo administration of 145D before challenge with PLP(139-151) results in a significant reduction in disease severity and incidence. Importantly, we demonstrate the ability of an MHC variant peptide to ameliorate established EAE. An advantage to this treatment is that the MHC variant peptide does not induce an acute hypersensitivity reaction. This is in contrast to previous work in the PLP(139-151) model demonstrating that anaphylactic shock resulting in death occurs upon rechallenge with the encephalitogenic peptide. Taken together, these data demonstrate the effectiveness of MHC anchor-substituted peptides in the treatment of EAE and suggest their utility in the treatment of other autoimmune disorders.     

Combined CXCR1/CXCR2 antagonism decreases radiation-induced alveolitis in the mouse

The mechanisms leading to the radiation-induced lung responses of alveolitis and fibrosis are largely unknown. Herein we investigated whether CXC receptor 1 and 2 antagonism with CXCL8((3-72))K11R/G31P (G31P), a protein that reduces neutrophil chemotaxis in acute inflammatory response models, decreases the lung response to radiation. Mice of the AKR/J (alveolitis/pneumonitis responding) and KK/HIJ (fibrosis) strains received 18 Gy whole-thorax irradiation and a subset of these mice were treated with G31P (500 μg/kg) three times per week from the day of irradiation until euthanasia due to respiratory distress symptoms or 20 weeks after radiation treatment. Irradiated mice of both strains receiving G31P survived longer than mice receiving radiation alone. Radiation- and G31P-treated AKR/J mice surviving to the end of the experiment developed significantly less alveolitis, as measured histologically, than mice receiving radiation alone, but this difference was not evident in KK/HIJ mice. Using immunohistochemistry, G31P treatment was shown to increase the numbers of Gr-1-positive cells (neutrophils) in the lungs of unirradiated mice relative to control mice injected with saline, but the antagonist did not alter the numbers of Gr-1-positive cells in the lungs of radiation-treated mice. We conclude that G31P treatment reduces radiation-induced alveolitis but not fibrosis in mice.     

IkappaB kinase is a critical regulator of chemokine expression and lung inflammation in respiratory syncytial virus infection

Respiratory syncytial virus (RSV) is the major etiologic agent of severe epidemic lower respiratory tract infections in infancy. Airway mucosal inflammation plays a critical role in the pathogenesis of RSV disease in both natural and experimental infections. RSV is among the most potent biological stimuli that induce the expression of inflammatory genes, including those encoding chemokines, but the mechanism(s) that controls virus-mediated airway inflammation in vivo has not been fully elucidated. Herein we show that the inoculation of BALB/c mice with RSV results in rapid activation of the multisubunit IkappaB kinase (IKK) in lung tissue. IKK transduces upstream activating signals into the rate-limiting phosphorylation (and proteolytic degradation) of IkappaBalpha, the inhibitory subunit that under normal conditions binds to the nuclear factor (NF)-kappaB complex and keeps it in an inactive cytoplasmic form. Mice treated intranasally with interleukin-10 or with a specific cell-permeable peptide that blocks the association of the catalytic subunit IKKbeta with the regulatory protein NEMO showed a striking reduction of lung NF-kappaB DNA binding activity, chemokine gene expression, and airway inflammation in response to RSV infection. These findings suggest that IKKbeta may be a potential target for the treatment of acute or chronic inflammatory diseases of the lung.