Augmentation Of Immune Response Research Articles

Molecular Analysis of Implantation Defects in Homeobox Gene Hoxa10-Deficient Mice

The success of embryo implantation depends on the receptivity of the uterus. Abdominal B class homeobox gene Hoxa10 is dynamically expressed around implantation, and is indispensable for establishing uterine receptivity. However, the exact mechanism through which HOXA10 exerts its function remains elusive. In this report, we investigated the molecular basis for the implantation failure caused by Hoxa10 deficiency using both knock-out mouse models and global gene expression profiling approaches. We demonstrated that augmented local immune response through T/B cells alone is not sufficient to explain the implantation defects observed in the Hoxa10-null uterus. We also uncovered a group of potential genes and signaling pathways that may participate in the downstream events mediated by HOXA10.

Erythropoietin treatment is associated with an augmented immune response to the influenza vaccine in hematologic patients

The objective of this study was to examine whether treatment with recombinant human erythropoietin (rHuEPO), previously found to be associated with a positive effect on cell-mediated immunity and humoral immunity (hepatitis B vaccine), is associated with an improved response to the seasonal influenza (flu) vaccine. Three groups received flu vaccine: healthy controls, hematologic patients not treated with rHuEPO ("No EPO" group), and hematologic patients receiving rHuEPO for their anemia ("EPO" group). Anti-flu Ab titer was measured (complement fixation test) from blood samples drawn before and approximately 3-4 weeks, 7-8 weeks and 4 months after vaccination. Nineteen healthy subjects were compared with 17 No EPO and 17 EPO patients. Mean ages were 59.5, 61.3, and 73.1 years, respectively (EPO patients were older; p = 0.005). In the healthy group, the percentage of those sustaining only a partial (twofold) response, a strong (fourfold or greater) response, and an overall response (combined partial and strong responses) were 31.6%, 57.9%, and 89.5%, respectively. In the No EPO group, values were 35.3%, 17.6%, and 52.9%, respectively. EPO group results were similar to those of the healthy controls: 23.5%, 58.8%, and 82.4% (p = 0.016, EPO vs. No EPO). In conclusion, hematologic patients (NoEPO group) respond poorly to the flu vaccine, compared with healthy subjects, and rHuEPO treatment is associated with an improved immune response to the flu vaccine in hematologic patients, with titers similar to those of healthy subjects.

De-regulated expression of microRNAs contributes to augmented T helper (TH) cell activity in experimental asthma

Background: Bronchial asthma is a heterogeneous chronic inflammatory disease, which is orchestrated by antigen-specific TH cells. By secreting cytokines, these cells shape the augmented immune response, which finally leads to structural changes of chronic inflamed airways. MicroRNA (miRNA), as small non-coding RNAs, are recognized as key regulatory elements in gene expression and have been linked with a number of complex human chronic inflammatory diseases. Yet, their implication in augmented TH cell activity in asthma has not been thoroughly investigated. Methods: T helper cell were isolated from murine lungs in the progression of ovalbumin- induced allergic airway inflammation and profiled by FACS, microarray and real-time RT-PCR. Results: Effector T helper cell subsets were FACS-sorted and characterized based on gene, protein and miRNA expression. These data were employed to identify TH- cell subset specific gene and miRNA expression levels. In addition, changes in gene and miRNA levels in the progression of experimental asthma were identified. Conclusion: The generated data provide evidence for TH cell subset specific miRNA expression as well as augmented expression of miRNA in the progression of experimental asthma. Furthermore, they permit the identification of miRNA-dependent and independent signalling pathways in TH cell subset important for disease development.

Loss of Cytoskeletal Transport during Egress Critically Attenuates Ectromelia Virus Infection In Vivo

Egress of wrapped virus (WV) to the cell periphery following vaccinia virus (VACV) replication is dependent on interactions with the microtubule motor complex kinesin-1 and is mediated by the viral envelope protein A36. Here we report that ectromelia virus (ECTV), a related orthopoxvirus and the causative agent of mousepox, encodes an A36 homologue (ECTV-Mos-142) that is highly conserved despite a large truncation at the C terminus. Deleting the ECTV A36R gene leads to a reduction in the number of extracellular viruses formed and to a reduced plaque size, consistent with a role in microtubule transport. We also observed a complete loss of virus-associated actin comets, another phenotype dependent on A36 expression during VACV infection. ECTV ΔA36R was severely attenuated when used to infect the normally susceptible BALB/c mouse strain. ECTV ΔA36R replication and spread from the draining lymph nodes to the liver and spleen were significantly reduced in BALB/c mice and in Rag-1-deficient mice, which lack T and B lymphocytes. The dramatic reduction in ECTV ΔA36R titers early during the course of infection was not associated with an augmented immune response. Taken together, these findings demonstrate the critical role that subcellular transport pathways play not only in orthopoxvirus infection in an in vitro context but also during orthopoxvirus pathogenesis in a natural host. Furthermore, despite the attenuation of the mutant virus, we found that infection nonetheless induced protective immunity in mice, suggesting that orthopoxvirus vectors with A36 deletions may be considered another safe vaccine alternative.

Augmented humoral immune response and decreased cell-mediated immunity by Aloe vera in rats

The present study was performed to explore the effect of aqueous extract of Aloe vera on parameters of humoral and cell-mediated immunity. Delayed-type hypersensitivity was assessed by measuring foot pad thickness following sensitisation by keyhole limpet haemocyanin injection and subsequently challenged by the same. Humoral immunity was assessed by measurement of haemagglutination titre to sheep red blood cells. Aloe vera (400mg/kg, p.o.) produced a significant decrease in foot pad thickness compared with the control group, and also significantly enhanced the secondary humoral immune response. Thus, these findings suggest that A. vera can modulate immune response by augmenting secondary humoral immunity and decreasing cell-mediated immunity.

Superior Induction of T Cell Responses to Conserved HIV-1 Regions by Electroporated Alphavirus Replicon DNA Compared to That with Conventional Plasmid DNA Vaccine

Vaccination using "naked" DNA is a highly attractive strategy for induction of pathogen-specific immune responses; however, it has been only weakly immunogenic in humans. Previously, we constructed DNA-launched Semliki Forest virus replicons (DREP), which stimulate pattern recognition receptors and induce augmented immune responses. Also, in vivo electroporation was shown to enhance immune responses induced by conventional DNA vaccines. Here, we combine these two approaches and show that in vivo electroporation increases CD8(+) T cell responses induced by DREP and consequently decreases the DNA dose required to induce a response. The vaccines used in this study encode the multiclade HIV-1 T cell immunogen HIVconsv, which is currently being evaluated in clinical trials. Using intradermal delivery followed by electroporation, the DREP.HIVconsv DNA dose could be reduced to as low as 3.2 ng to elicit frequencies of HIV-1-specific CD8(+) T cells comparable to those induced by 1 μg of a conventional pTH.HIVconsv DNA vaccine, representing a 625-fold molar reduction in dose. Responses induced by both DREP.HIVconsv and pTH.HIVconsv were further increased by heterologous vaccine boosts employing modified vaccinia virus Ankara MVA.HIVconsv and attenuated chimpanzee adenovirus ChAdV63.HIVconsv. Using the same HIVconsv vaccines, the mouse observations were supported by an at least 20-fold-lower dose of DNA vaccine in rhesus macaques. These data point toward a strategy for overcoming the low immunogenicity of DNA vaccines in humans and strongly support further development of the DREP vaccine platform for clinical evaluation.

Characterization of the rabbit neonatal Fc receptor (FcRn) and analyzing the immunophenotype of the transgenic rabbits that overexpresses FcRn.

The neonatal Fc receptor (FcRn) regulates IgG and albumin homeostasis, mediates maternal IgG transport, takes an active role in phagocytosis, and delivers antigen for presentation. We have previously shown that overexpression of FcRn in transgenic mice significantly improves the humoral immune response. Because rabbits are an important source of polyclonal and monoclonal antibodies, adaptation of our FcRn overexpression technology in this species would bring significant advantages. We cloned the full length cDNA of the rabbit FcRn alpha-chain and found that it is similar to its orthologous analyzed so far. The rabbit FcRn - IgG contact residues are highly conserved, and based on this we predicted pH dependent interaction, which we confirmed by analyzing the pH dependent binding of FcRn to rabbit IgG using yolk sac lysates of rabbit fetuses by Western blot. Using immunohistochemistry, we detected strong FcRn staining in the endodermal cells of the rabbit yolk sac membrane, while the placental trophoblast cells and amnion showed no FcRn staining. Then, using BAC transgenesis we generated transgenic rabbits carrying and overexpressing a 110 kb rabbit genomic fragment encoding the FcRn. These transgenic rabbits – having one extra copy of the FcRn when hemizygous and two extra copies when homozygous - showed improved IgG protection and an augmented humoral immune response when immunized with a variety of different antigens. Our results in these transgenic rabbits demonstrate an increased immune response, similar to what we described in mice, indicating that FcRn overexpression brings significant advantages for the production of polyclonal and monoclonal antibodies.

Modified CD4+ T-cell response in recipients of old cardiac allografts

With an increasing demand, organs from elderly donors are more frequently utilized for transplantation. Herein, we analyzed the impact of donor age on CD4(+) T-cell responses with regard to regulatory and effector mechanisms. Young (3months) BM12 recipients were engrafted with young or old (18months) B6 cardiac allografts. Systemic CD4(+) T-cell responses and intragraft changes were monitored and compared to age-matched syngenic transplant controls. While elderly, nonmanipulated hearts contained significantly elevated frequencies of donor-derived leukocytes prior to transplantation, allograft survival was age-independent. T-cell activation, however, was delayed and associated with a compromised immune response in mixed lymphocyte cultures (MLR; P=0.0002) early after transplantation (day 14). During the time course after transplantation, recipients of old grafts demonstrated an augmented immune response as shown by significantly higher frequencies of activated CD4(+) T-cells and a stronger in vitro alloreactivity (MLR; ELISPOT; P<0.01). In parallel, frequencies of regulatory T-cells had increased systemically and overall fewer CD4(+) T-cells were detected intragraft. Interestingly, changes in the CD4(+) T-cell response were not reflected by graft morphology. Of note, transplantation of young and old syngenic hearts did not show age-related differences of the CD4(+) T-cells response suggesting that old grafts can recover from a period of short cold ischemia time. Our data suggest that donor age is associated with an augmented CD4(+) T-cells response which did not affect graft survival in our model. These findings contribute to a better understanding of the immune response following the engraftment of older donor organs.

Immunity to the melanoma inhibitor of apoptosis protein (ML-IAP; livin) in patients with malignant melanoma

Therapeutic targeting of melanoma antigens frequently focuses on the melanocyte differentiation or cancer-testis families. Antigen-loss variants can often result, as these antigens are not critical for tumor cell survival. Exploration of functionally relevant targets has been limited. The melanoma inhibitor of apoptosis protein (ML-IAP; livin) is overexpressed in melanoma, contributing to disease progression and treatment resistance. Improved understanding of the significance of ML-IAP immune responses in patients has possible therapeutic applications. We found ML-IAP frequently expressed in melanoma metastases by immunohistochemistry. To assess spontaneous immunity to ML-IAP, an overlapping peptide library representing full-length protein was utilized to screen cellular responses in stage I–IV patients and healthy controls by ELISPOT. A broad array of CD4+ and CD8+ cellular responses against ML-IAP was observed with novel class I and class II epitopes identified. Specific HLA-A*0201 epitopes were analyzed further for frequency of reactivity. The generation of specific CD4+ and cytotoxic T cells revealed potent functional capability including cytokine responsiveness to melanoma cell lines and tumor cell killing. In addition, recombinant ML-IAP protein used in an ELISA demonstrated high titer antibody responses in a subset of patients. Several melanoma patients who received CTLA-4 blockade with ipilimumab developed augmented humoral immune responses to ML-IAP as a function of treatment which was associated with beneficial clinical outcomes. High frequency immune responses in melanoma patients, associations with favorable treatment outcomes, and its essential role in melanoma pathogenesis support the development of ML-IAP as a disease marker and therapeutic target.Electronic supplementary materialThe online version of this article (doi:10.1007/s00262-011-1124-1) contains supplementary material, which is available to authorized users.

Enhanced Control of Pathogenic Simian Immunodeficiency Virus SIVmac239 Replication in Macaques Immunized with an Interleukin-12 Plasmid and a DNA Prime-Viral Vector Boost Vaccine Regimen

DNA priming has previously been shown to elicit augmented immune responses when administered by electroporation (EP) or codelivered with a plasmid encoding interleukin-12 (pIL-12). We hypothesized that the efficacy of a DNA prime and recombinant adenovirus 5 boost vaccination regimen (DNA/rAd5) would be improved when incorporating these vaccination strategies into the DNA priming phase, as determined by pathogenic simian immunodeficiency virus SIVmac239 challenge outcome. The whole SIVmac239 proteome was delivered in 5 separate DNA plasmids (pDNA-SIV) by EP with or without pIL-12, followed by boosting 4 months later with corresponding rAd5-SIV vaccine vectors. Remarkably, after repeated low-dose SIVmac239 mucosal challenge, we demonstrate 2.6 and 4.4 log reductions of the median SIV peak and set point viral loads in rhesus macaques (RMs) that received pDNA-SIV by EP with pIL-12 compared to the median peak and set point viral loads in mock-immunized controls (P < 0.01). In 5 out of 6 infected RMs, strong suppression of viremia was observed, with intermittent "blips" in virus replication. In 2 RMs, we could not detect the presence of SIV RNA in tissue and lymph nodes, even after 13 viral challenges. RMs immunized without pIL-12 demonstrated a typical maximum of 1.5 log reduction in virus load. There was no significant difference in the overall magnitude of SIV-specific antibodies or CD8 T-cell responses between groups; however, pDNA delivery by EP with pIL-12 induced a greater magnitude of SIV-specific CD4 T cells that produced multiple cytokines. This vaccine strategy is relevant for existing vaccine candidates entering clinical evaluation, and this model may provide insights into control of retrovirus replication.

Pharmacology and immune modulating properties of 5-androstene-3β,7β,17β-triol, a DHEA metabolite in the human metabolome

Androst-5-ene-3β,7β,17β-triol (βAET) is an anti-inflammatory metabolite of DHEA that is found naturally in humans, but in rodents only after exogenous DHEA administration. Unlike DHEA, C-7-oxidized DHEA metabolites cannot be metabolized into potent androgens or estrogens, and are not peroxisome proliferators in rodents. The objective of our current studies was to characterize the pharmacology of βAET to enable clinical trials in humans. The pharmacology of βAET was characterized by pharmacokinetics, drug metabolism, nuclear hormone receptor interactions, androgenicity, estrogenicity, and systemic toxicity studies. βAET's acute anti-inflammatory activity and immune modulating characteristics were measured in vitro in RAW264.7 cells and in vivo in murine models with parenteral administration. βAET was rapidly metabolized and cleared from circulation in mice and monkeys. βAET was weakly androgenic and estrogenic in immature rodents, but not bound by androgen, estrogen, progesterone, or glucocorticoid nuclear hormone receptors. βAET did not induce peroxisome proliferation, nor was it systemically toxic or trophic for sex hormone responsive tissues in mature rats and monkeys. βAET significantly attenuated acute inflammation both in vitro and in vivo, augmented immune responses in adult mice, and reversed immune senescence in aged mice. βAET may contribute to the anti-inflammatory activity in rodents attributed to DHEA. Unlike DHEA, βAET's anti-inflammatory activity cannot be ascribed to activation of PPARs, androgen, or estrogen nuclear hormone receptors. Exogenous βAET is unlikely to produce untoward toxicity or hormonal perturbations in humans.

Identification of novel small molecule inducers of endothelium-driven innate immunity (54.10)

Abstract The endothelium plays a critical role in promoting inflammation in cardiovascular disease and other chronic inflammatory conditions. Conversely, an augmented immune response can be protective against microbial pathogens and in cancer immunotherapy. Many small molecule screens have sought to identify agents that prevent endothelial cell activation. Yet, small molecule screens to identify agents that induce endothelial cell activation have not been reported. In this regard, a bioassay was developed which identifies activated endothelium by its capacity to trigger MIP1 beta from primary monocytes. Subsequently, a 642 compound library of 39 distinctive scaffolds generated by diversity oriented synthesis was screened for small molecules that activated the endothelium. From the identified inflammatory compounds, 96 analogs of one particular class of compounds were efficiently prepared by solid phase split-and-pool synthesis. Structure-function analysis combined with transcriptional profiling of active and inactive analogues identified inflammatory gene networks induced exclusively by the active compound. The identification of a family of chemical probes that augment innate immunity through endothelial cell activation provides a framework for understanding gene networks involved in endothelial inflammation as well as the development of novel endothelium-driven immunotherapeutic agents.

T cell expression of NOX2 regulates T helper differentiation (113.10)

Abstract Absence of phagocyte NADPH oxidase (NOX2) activity causes chronic granulomatous disease (CGD), a primary immunodeficiency characterized by recurrent bacterial infections. In seeming contradiction, immune responses to agents such as H. pylori and influenza imply an altered or augmented adaptive immune response in CGD. We have shown NOX2 expression in T cells, and oxidase deficient T cells demonstrate Th1 skewed cytokine secretion upon in vitro stimulation. The goal of this study was to determine if these differences are T cell inherent, or if other cells promote T helper polarization. Activation of purified naive CD4+ T cells from NOX2-deficient mice led to augmented IFN-γ and diminished IL-4 production, consistent with a Th1 skewing of naïve T cells. This was supported by enhanced expression of the transcription factor T-bet and lower levels of GATA-3. Similar to NOX2-deficient cells, Th2-biased BALB/c T cells treated with the antioxidant N-acetyl cysteine produced increased IFN-γ and decreased IL-4 as compared to untreated controls. Inhibition of TCR-induced STAT5 phosphorylation was identified as a potential mechanism for skewed T helper differentiation. Stimulation of TCR-transgenic, OT-II T cells in vitro with NOX2-deficient splenic APC produced similar amounts of IL-4, IL-17, and IFN-γ as compared to those incubated with wild type APC, supporting the conclusion that NOX2 can regulate the adaptive immune response in a T cell inherent fashion.

Diversity through phosphine catalysis identifies octahydro-1,6-naphthyridin-4-ones as activators of endothelium-driven immunity

The endothelium plays a critical role in promoting inflammation in cardiovascular disease and other chronic inflammatory conditions, and many small-molecule screens have sought to identify agents that prevent endothelial cell activation. Conversely, an augmented immune response can be protective against microbial pathogens and in cancer immunotherapy. Yet, small-molecule screens to identify agents that induce endothelial cell activation have not been reported. In this regard, a bioassay was developed that identifies activated endothelium by its capacity to trigger macrophage inflammatory protein 1 beta from primary monocytes. Subsequently, a 642-compound library of 39 distinctive scaffolds generated by a diversity-oriented synthesis based on the nucleophilic phosphine catalysis was screened for small molecules that activated the endothelium. Among the active compounds identified, the major classes were synthesized through the sequence of phosphine-catalyzed annulation, Tebbe reaction, Diels-Alder reaction, and in some cases, hydrolysis. Ninety-six analogs of one particular class of compounds, octahydro-1,6-naphthyridin-4-ones, were efficiently prepared by a solid-phase split-and-pool technique and by solution phase analog synthesis. Structure-function analysis combined with transcriptional profiling of active and inactive octahydro-1,6-naphthyridin-4-one analogs identified inflammatory gene networks induced exclusively by the active compound. The identification of a family of chemical probes that augment innate immunity through endothelial cell activation provides a framework for understanding gene networks involved in endothelial inflammation as well as the development of novel endothelium-driven immunotherapeutic agents.

Hypomorphic Mutation in the Site-1 Protease Mbtps1 Endows Resistance to Persistent Viral Infection in a Cell-Specific Manner

The prototypic arenavirus lymphocytic choriomeningitis virus (LCMV), which naturally persists in rodents, represents a model for HIV, HBV, and HCV. Cleavage of the viral glycoprotein precursor by membrane-bound transcription factor peptidase, site 1 (Mbtps1 or site-1 protease), is crucial for the life cycle of arenaviruses and therefore represents a potential target for therapy. Recently, we reported a viable hypomorphic allele of Mbtps1 (woodrat) encoding a protease with diminished enzymatic activity. Using the woodrat allele, we examine the role of Mbtps1 during persistent LCMV infection. Surprisingly, Mbtps1 inhibition limits persistent but not acute viral infection and is associated with an organ/cell type-specific decrease in viral titers. Analysis of bone marrow-derived dendritic cells from woodrat mice supports their specific role in resolving persistent viral infection. These results support in vivo targeting of Mbtps1 in the treatment of arenavirus infections and demonstrate a critical role for dendritic cells in persistent viral infections.

Gp130 on macrophages/granulocytes modulates inflammation during experimental tuberculosis

gp130 is a common receptor chain for cytokines such as interleukin (IL)-27 and IL-6. During experimental tuberculosis (TB), IL-27 prevents optimal antimycobacterial protection and limits the pathological sequelae of chronic inflammation. The anti-inflammatory properties of IL-27 have been attributed mainly to its suppressive effect on T helper (TH) cells. However, because gp130 cytokines also suppress the inflammatory immune response of macrophages, IL-27 may also regulate inflammation by limiting the secretion of pro-inflammatory cytokines. To specifically address the role of gp130 cytokines on macrophages, the outcome of experimental TB was analysed in macrophage/neutrophil-specific gp130-deficient (LysM cre gp130 loxP/loxP) mice. In these mice, the enhanced induction of inflammatory cytokines and increased expression of the inducible nitric oxide synthase (NOS2) and LRG47 was linked to a greatly augmented TH17 immune response and matrix metalloproteinase (MMP)-9 expression. However, this amplified inflammatory immune response in Mtb-infected LysM cre gp130 loxP/loxP mice was not associated with reduced bacterial loads and/or accelerated pathology. Our study revealed an immunoregulatory function of gp130 cytokines on macrophages/granulocytes, which is, however, not critical for modulating the outcome of TB.

Characteristics of severe adverse events after peptide vaccination for advanced cancer patients: Analysis of 500 cases

The purpose of this study was to investigate severe adverse events (SAEs) after therapeutic peptide vaccination for advanced cancer patients. We investigated SAEs following personalized peptide vaccinations in 500 advanced cancer patients, including 174 prostate, 74 colon, 51 pancreatic and 43 gastric cancer patients. The number of vaccination cycles varied widely, from 3 to 112. The severity of adverse events was scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 3, and events with a grade of >3 were defined as SAEs and were evaluated by the Institutional Safety Evaluation Committee. A total of 215 SAEs in 102 patients were recorded during the vaccine trials. The main causes for these events were cancer progression (152 SAEs in 78 patients), combined cancer treatments other than vaccination (35 in 21 patients), diseases other than cancer (20 in 19 patients), peptide vaccines (6 in 6 patients) and suicide (1 in 1 patient). The 6 vaccine-related SAEs, all grade 3, consisted of skin reactions at each injection site, cellulitis around the injection site, edemas of the head and neck regions, colitis, rectal bleeding and bladder-vaginal fistulae. Both cellular and humoral responses to the vaccinated peptides were highly boosted in all 6 of these patients, indicating the involvement of augmented immune responses in these SAEs. The clinical responses in these 6 patients consisted of 2 partial responses and 4 stable diseases. The majority of SAEs after peptide vaccination for advanced cancer patients were caused by cancer progression. The appearance of vaccine-related SAEs, except inflammatory injection site reactions, was unexpected, and fortunately the incidence was very low. Our results suggest that physicians should be on guard for these rare SAEs associated with augmented immune responses.

IL-17 Is Necessary for Host Protection against Acute-Phase Trypanosoma cruzi Infection

IL-17A is a key cytokine that induces inflammatory responses through the organized production of inflammatory cytokines, such as IL-6, TNF-alpha, and GM-CSF, and induces neutrophil migration. The roles of IL-17A in infection of intracellular protozoan parasites have not been elucidated, although augmented immune responses by IL-17A are important for the resolution of some bacterial and fungal infections. Therefore, we experimentally infected IL-17A-deficient (IL-17A(-/-)) mice with Trypanosoma cruzi. IL-17A(-/-) mice had a lower survival rate and prolonged worse parasitemia compared with control C57BL/6 wild-type (WT) mice postinfection. In the infected IL-17A(-/-) mice, multiple organ failure was observed compared with WT mice, as reflected by the marked increase in serologic markers of tissue injury, such as aspartate aminotransferase, which resulted in increased mortality of IL-17A(-/-) mice. Expression of cytokines, such as IFN-gamma, IL-6, and TNF-alpha, was lower in liver-infiltrating cells from the IL-17A(-/-) mice compared with WT mice. A similar defect was observed in the expression of neutrophil enzymes, such as myeloperoxidase and lipoxygenase, whereas cellular infiltration into the infected tissues was not affected by IL-17A deficiency. These results suggested that the efficient activation of immune-related cells critical for the killing of T. cruzi was impaired in the absence of IL-17A, resulting in the greater susceptibility of those mice to T. cruzi infection. From these results, we conclude that IL-17A is important for the resolution of T. cruzi infection.

Early-life viral infection and allergen exposure interact to induce an asthmatic phenotype in mice

BackgroundEarly-life respiratory viral infections, notably with respiratory syncytial virus (RSV), increase the risk of subsequent development of childhood asthma. The purpose of this study was to assess whether early-life infection with a species-specific model of RSV and subsequent allergen exposure predisposed to the development of features of asthma.MethodsWe employed a unique combination of animal models in which BALB/c mice were neonatally infected with pneumonia virus of mice (PVM, which replicates severe RSV disease in human infants) and following recovery, were intranasally sensitised with ovalbumin. Animals received low-level challenge with aerosolised antigen for 4 weeks to elicit changes of chronic asthma, followed by a single moderate-level challenge to induce an exacerbation of inflammation. We then assessed airway inflammation, epithelial changes characteristic of remodelling, airway hyperresponsiveness (AHR) and host immunological responses.ResultsAllergic airway inflammation, including recruitment of eosinophils, was prominent only in animals that had recovered from neonatal infection with PVM and then been sensitised and chronically challenged with antigen. Furthermore, only these mice exhibited an augmented Th2-biased immune response, including elevated serum levels of anti-ovalbumin IgE and IgG1 as well as increased relative expression of Th2-associated cytokines IL-4, IL-5 and IL-13. By comparison, development of AHR and mucous cell change were associated with recovery from PVM infection, regardless of subsequent allergen challenge. Increased expression of IL-25, which could contribute to induction of a Th2 response, was demonstrable in the lung following PVM infection. Signalling via the IL-4 receptor α chain was crucial to the development of allergic inflammation, mucous cell change and AHR, because all of these were absent in receptor-deficient mice. In contrast, changes of remodelling were evident in mice that received chronic allergen challenge, regardless of neonatal PVM infection, and were not dependent on signalling via the IL-4 receptor.ConclusionIn this mouse model, interaction between early-life viral infection and allergen sensitisation/challenge is essential for development of the characteristic features of childhood asthma, including allergic inflammation and a Th2-biased immune response.

Erythropoietin Treatment Is Associated with Augmented Immune Response to the Influenza Vaccine in Hematologic Patients.

Abstract 1637Poster Board I-663 IntroductionRecombinant human erythropoietin (EPO) has been effective in treating various types of anemia. EPO receptors on non-erythroid cells suggest that EPO may also have non-erythroid effects. Indeed, we have previously shown that EPO has anti-neoplastic immunomodulating effects in both patients and mice (Mittelman PNAS 2001; Mittelman Eur J Haematol 2004). EPO effects were demonstrated in both the cellular and humoral immune systems (Katz Acta Haematol 2005; Katz Eur J Immunol 2007; Prutchi-Sagiv Br J Haematol 2006; Prutchi-Sagiv Exp Hematol 2008; Lifshitz Mol Immunol 2009). Hassan et al. (Ren Fail 2003) have reported that patients with renal failure treated with EPO had a higher antibody (Ab) titer in response to the Hepatitis B vaccine. We therefore hypothesized that EPO plays a general role in augmenting the immune response. To test this hypothesis we examined the effect of EPO on the antibody response to the seasonal influenza (flu) vaccine. MethodsThree groups, all receiving the flu vaccine, were tested: A) Healthy controls (HC), B) Hematologic patients not receiving EPO (H-NoEPO), C) Hematologic patients on EPO for anemia (H-EPO). Mean ages of the participants [95% CI] were 59.5 [56.5-62.4], 59.6 [50.9-68.2], and 73.9 [68.8-79.0] respectively. Flu vaccine and EPO were ordered by the attending physicians only, irrespective of the study. Blood samples were drawn prior to and 3 weeks, 7 weeks and 4 months after the flu vaccination. Anti-flu Ab titer was measured using the complement fixation test. The results are presented as the number (percentage) of tested individuals who responded with at least two- or four-fold increase in anti-flu titers, compared to their baseline. P value represents comparison of H-EPO to H-NoEPO. ResultsOf the HC individuals, 90% doubled (at least) and 58% quadrupled their anti-flu Ab titers. Of the H-NoEPO patients only 56% doubled and 19% quadrupled their titers. However, 72% of the H-EPO patients doubled and 56% quadrupled their titers, a response approaching that of healthy controls, despite their being significantly older. Conclusions1) Hematologic patients respond poorly to the flu vaccine, compared to healthy subjects. 2) EPO treatment is associated with an improved immune response to the flu vaccine in hematologic patients. This suggests that EPO may serve as an immune augmenting agent for the flu vaccine and possibly other vaccines as well.TableAnti-flu Ab response, indicating the number of subjects (N) and the percent (%) having at least two- and/or four-fold increased Ab titers, compared to the baseline levels before vaccination. P value is for comparison of H-EPO and H-NoEPO.HCH-NoEPOH-EPOPTotal N191618Increase ≥ 2-fold N (%)17 (90)9 (56)13 (72)0.33Increase ≥ 4-fold N (%)11 (58)3 (19)10 (56)0.028 DisclosuresOff Label Use: Non erythroid effects: immune, anti-cancer (all under investigation). Prutchi-Sagiv:BioGAL- Start up (inactive): Equity Ownership. Mittelman:BioGAL- Start up (inactive): Equity Ownership, Patents & Royalties.