Department of Medicine, Saint Louis University School of Medicine and National Institute of Allergy and Infectious Diseases Vaccine Treatment and Evaluation Unit, 1100 S. Grand Blvd (DRC-8), St. Louis, MO 63104, USA. firstname.lastname@example.org
Smallpox vaccination with replication deficient vaccinia strains such as Modified Vaccinia Ankara (MVA) may induce protective immunity with improved safety and tolerability profiles compared with currently available smallpox vaccines. Ninety subjects were randomized equally to six groups in a partially blinded, randomized, controlled clinical trial. IMVAMUNE (MVA-BN, Bavarian Nordic A/S, Kvistgård, Denmark) vaccine or placebo was administered at Study Days 0 and 28 by subcutaneous or intramuscular injection and five groups were challenged with Dryvax at study Day 112. Vaccination with two doses of IMVAMUNE was safe and well tolerated compared to Dryvax. IMVAMUNE produced comparable cellular and humoral immune responses to one dose of Dryvax and the immunity induced appears robust 90 days post-vaccination by evidence of attenuated primary cutaneous reaction responses following Dryvax. IMVAMUNE vaccination prior to Dryvax reduced virus replication at the Dryvax site, decreased the size of the primary cutaneous lesion, and decreased the time to healing but did not completely ameliorate the immune response.
The purpose of this study was to test the therapeutic potential of monomethoxypolyethylene glycol (mPEG) conjugated-allergen using a rodent model of allergic asthma. Previously, this conjugate has been shown to possess the dual capacity of inducing long-term ovalbumin (OA)-specific suppression of the antibody response and inactivating rat mast cells that have been sensitized with murine IgE to OA. Ovalbumin sensitized and challenged Brown Norway rats were studied. Fourteen days after sensitization, a test group of six rats received mPEG-OA solution intratracheally and were challenged 30 min later with aerosolized OA. Another group of seven sensitized rats was similarly challenged with OA 30 min after intratracheal administration of normal saline. A group of six sensitized rats received mPEG-OA solution intratracheally but were challenged with normal saline. Another group of seven sensitized rats received mPEG-BSA solution intratracheally and were challenged 30 min later with aerosolized OA. A final group of five unsensitized rats were neither challenged nor medicated intratracheally. Pulmonary resistance was measured before and for 8 h following inhalation challenge. mPEG-OA treatment had an inhibitory effect on the allergic late airway response, but the early response was not significantly altered. Both mPEG-OA and mPEG-BSA reduced the total cells, eosinophils and neutrophils, in bronchoalveolar lavage and decreased the expression of IL-4, IL-5 and IFN-gamma mRNA. In conclusion, mPEG-OA can prevent the development of allergen-induced late airway responses and reduce airway Th2-type cytokine expression whereas mPEG conjugated to an irrelevant antigen (BSA) is anti-inflammatory but does not affect the late response.
BACKGROUND: Gamma-delta (gammadelta) T cells regulate immune responses to foreign protein at mucosal surfaces. Whether they can modify allergen-induced early (EAR) and late airway responses (LAR) is unknown. OBJECTIVE: We have tested the hypothesis that the CD8+ subtype of gammadelta T cells decreases allergen-induced LAR and airway eosinophilia in the rat. METHODS: Brown Norway rats were administered, intraperitoneally, 3.5 x 10(4) lymph node CD8+gammadelta T cells from naive or sensitized rats. The recipients were sensitized to ovalbumin (OVA) in Al(OH)(3) 3 days after cell transfer and challenged with aerosolized OVA 14 days later. Serum IgE was measured before allergen challenge. After challenge, lung resistance was monitored for 8 hours and then bronchoalveolar lavage (BAL) was analyzed for eosinophil major basic protein (MBP), IL-4, IL-5, IL-13, and IFN-gamma messenger RNA-expressing cells. RESULTS: gammadelta T cells from naive donors significantly decreased LAR in OVA-challenged sensitized rats, whereas MBP(+) eosinophils were decreased by both gammadelta T cells from naive and sensitized donors. EAR and serum IgE levels were unchanged. The expression of IL-4, IL-5, and IL-13 by BAL cells of gammadelta T cell recipients was attenuated compared with OVA-challenged controls. This was accompanied by an increase in the expression of IFN-gamma. CONCLUSIONS: Our results are consistent with a suppressive role of CD8+gammadelta T cells on allergic airway responses. However, only gammadelta T cells from naive donors inhibit LAR.
IL-12 and IL-4 are critical cytokines for Th1 and Th2 differentiation, respectively. To assess the roles of these cytokines in the development of experimental immune-mediated blepharoconjunctivitis (EC) in Brown Norway (BN) rats, their effects were tested either in vitro or in vivo. Draining lymph node cells from rats immunized with ragweed pollen (RW) in Al(OH)3 were collected and cultured for 3 days with RW in the presence of IL-4, IL-12, or PBS as a control. After harvesting the culture supernatants for cytokine ELISA and the cells for cytokine reverse transcriptase-polymerase chain reaction, 10 million cells were injected intravenously into syngeneic recipient rats (n = 12 per group). The rats were challenged with RW by eye drops 4 days after transfer. Eyes were harvested for histology 24 h later. Furthermore, IL-12 (500 ng per injection) or PBS was injected intraperitoneally every other day seven times from the day of active immunization (n = 6 per group). One day after the last injection, rats were challenged and EC was evaluated as above. Transfer of cells with IL-4 in vitro augmented eosinophilic infiltration in the conjunctiva compared with the other two groups, whereas IL-12 in vitro suppressed eosinophilic infiltration and increased lymphocytic infiltration. Interferon-gamma production was augmented by IL-12. IL-4 RNA expression was augmented by IL-4. IL-12 administration in vivo augmented lymphocytic infiltration in the conjunctiva without affecting infiltration of eosinophils. In conclusion, IL-4 and IL-12 either in vitro or in vivo augmented Th2 and Th1 immunity, respectively, thus leading to distinct histological features of EC.
Gold salts are beneficial in the treatment of rheumatoid arthritis but may induce immune-mediated disorders in predisposed patients. Gold salts induce Th2-dependent autoimmunity in Brown-Norway (BN) rats but not in Lewis (LEW) rats. The aim of this study was to define molecular targets of gold salts and to approach why LEW rats are resistant. Gold salts act on early steps of transduction in T cells from BN and LEW rats since they trigger tyrosine phosphorylation of numerous proteins including p56(lck) and a calcium signal which results in IL-4 and IFN-gamma expression by BN and LEW T cells. However, the IL-4 response was favored in BN spleen cells in vitro and in vivo. IFN-gamma, produced in part by CD8(+) cells, contributes to the resistance of LEW rats since gold salt-injected LEW rats receiving anti-CD8 or anti-IFN-gamma mAb displayed the parameters characteristics of gold salt-induced Th2 autoimmunity although to a lesser extent than in BN rats. Gold salts transduce a signal in BN and LEW spleen cells resulting in IL-4 and IFN-gamma gene transcription with a preferential IL-4 response in BN rats, a Th2-prone strain, while IFN-gamma contributes to the resistance of LEW rats.
Heaves is a common condition of horses of cold climate that is characterized by small airway inflammation and obstruction following exposure of susceptible horses to moldy hay and straw. It has been shown that helper T lymphocytes (Th) orchestrate the inflammatory response in asthma and in various animal models of allergic lung diseases by the release of Th2-type cytokines. Results of previous studies indicate that a predominant expression of Th2-type response by airway cells may also be present in heaves. To evaluate the temporal mRNA expression of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) type cytokines in heaves and their relationship to clinical disease, we studied the pulmonary mechanics and cytokine mRNA expression (IL-4, IL-5 and IFN-gamma) in bronchoalveolar lavage lymphocytes of horses with heaves (n=6) and control (n=6) before and after 24h and 9 days of continuous natural inhalation challenge. Starting 24h after challenge horses with heaves, but not control horses, had a significant increase in pulmonary elastance and the number of lymphocytes expressing mRNA for IL-4 and IL-5. These changes were further increased at 9 days, at which time the number of cells positive for IFN-gamma mRNA was decreased. In this study we have shown that BAL lymphocytes of horses with heaves during clinical exacerbation have a predominant Th2-type cytokine response and that this response coincides in time with the presence of airway obstruction.
T lymphocytes are exquisitely sensitive to the antiproliferative effects of nitric oxide. We examined the effects of oral administration of two nitric oxide synthase inhibitors, Nw-nitro-L-arginine methyl ester (L-NAME) and L-N6-(1-iminoethyl)lysine (L-NIL), on the course of T cell-dependent autoimmune interstitial nephritis in Brown Norway rats. Kidneys from rats immunized to produce interstitial nephritis display a net generation of nitric oxide end products. By immunohistochemical staining, the cytokine-inducible nitric oxide synthase (iNOS) is expressed in cortical tubular epithelial cells. Treatment with either inhibitor results in markedly more severe disease following immunization. Animals receiving L-NAME were hypertensive, while those treated with L-NIL, a highly selective inhibitor of iNOS, were not. Evaluation of the expression of IFN-gamma, IL-2, and IL-4 in diseased kidneys by quantitative reverse transcriptase-PCR demonstrated that L-NAME-treated animals displayed significantly augmented levels of IFN-gamma and IL-2 with preserved ratios of IFN-gamma/IL-4 and IL-2/IL-4, while L-NIL-treated animals had augmented levels of IL-2 and IFN-gamma with augmented IFN-gamma/IL-4 and IL-2/IL-4 ratios. Animals treated with L-NAME or L-NIL both had augmented Ag-specific IgG responses. The L-NAME group demonstrated increases in both the IgG2a and IgG1 subtypes, with a constant IgG2a/IgG1 ratio, while the L-NIL group demonstrated an increase in the ratio of the IgG2a/IgG1 response. These Ab and cytokine data suggest that the L-NIL-treated animals had a skewing of their immune response toward a Th1-like response. We conclude that in autoimmune interstitial nephritis, generation of nitric oxide through the iNOS pathway has host-protective effects, and suggest that this may be broadly applicable to T cell-mediated pathologies.
The events subsequent to antigen challenge in allergic asthmatics involve the synthesis of pro-inflammatory cytokines. However, little is known how cytokine gene activation prior to allergen challenge may influence this series of events, nor how cytokine gene expression is related to antigen-induced alterations in lung function. Using a novel in vitro explant technique, we hypothesized that the local expression of cytokines influenced the development of antigen-induced late-onset airway responses, and that alterations in cytokine messenger ribonucleic acid (mRNA) expression were associated with antigen-induced changes in airway luminal area. Explants were prepared from excised lungs of ovalbumin-sensitized Brown-Norway rats. Airways were challenged by direct application of ovalbumin or an irrelevant control antigen. Cryostat sections of explants were used for in situ hybridization and mRNA for interleukin (IL)-2, IL-4 and interferon (IFN)-gamma were detected using radiolabelled probes. We found that the presence of high numbers of cells expressing IFN-gamma and IL-2 mRNA within the airways attenuated the development of antigen-induced late airway responses in sensitized rat lung explants. Furthermore, we observed that cytokine mRNA for IL-4 was significantly increased following allergen exposure in sensitized lung explants exhibiting late airway responses. This study implicates the local expression of interferon-gamma and interleukin-2 messenger ribonucleic acid in the failure of sensitized rat lung explants to exhibit late airway responses, and provides evidence linking local interleukin-4 messenger ribonucleic acid expression to the sequelae of events occurring as a result of antigen exposure within the airways.