Cytokines induced by Sendai virus in human peripheral blood leukocytes

Oncolysis by paramyxoviruses: multiple mechanisms contribute to therapeutic efficiency

Oncolytic paramyxoviruses include some strains of Measles, Mumps, Newcastle disease, and Sendai viruses. All these viruses are well equipped for promoting highly specific and efficient malignant cell death, which can be direct and/or immuno-mediated. A number of proteins that serve as natural receptors for oncolytic paramyxoviruses are frequently overexpressed in malignant cells. Therefore, the preferential interaction of paramyxoviruses with malignant cells rather than with normal cells is promoted. Due to specific genetic defects of cancer cells in the interferon (IFN) and apoptotic pathways, viral replication has the potential to be promoted specifically in tumors. Viral mediation of syncytium formation (a polykaryonic structure) promotes intratumoral paramyxo-virus replication and spreading, without exposure to host neutralizing antibodies. So, two related processes: efficient intratumoral infection spread as well as the consequent mass malignant cell death, both are enhanced. In general, the paramyxoviruses elicit strong anticancer innate and adaptive immune responses by triggering multiple danger signals. The paramyxoviruses are powerful inducers of IFN and other immuno-stimulating cytokines. These viruses efficiently promote anticancer activity of natural killer cells, dendritic cells, and cytotoxic T lymphocytes. Moreover, a neuraminidase (sialidase), a component of the viral envelope of Newcastle Disease, Mumps, and Sendai viruses, can cleave sialic acids on the surface of malignant cells thereby unmasking cancer antigens and exposing them to the immune system. These multiple mechanisms contribute to therapeutic efficacy of oncolytic paramyxovi-ruses and are responsible for encouraging results in preclinical and clinical studies.

Interleukin-1β mediates virus-induced m2 muscarinic receptor dysfunction and airway hyperreactivity

Respiratory viral infections are associated with the majority of asthma attacks. Inhibitory M2 receptors on parasympathetic nerves, which normally limit acetylcholine (ACh) release, are dysfunctional after respiratory viral infection. Because IL-1β is up-regulated during respiratory viral infections, we investigated whether IL-1β mediates M2 receptor dysfunction during parainfluenza virus infection. Virus-infected guinea pigs were pretreated with the IL-1β antagonist anakinra. In the absence of anakinra, viral infection increased bronchoconstriction in response to vagal stimulation but not to intravenous ACh, and neuronal M2 muscarinic receptors were dysfunctional. Pretreatment with anakinra prevented virus-induced increased bronchoconstriction and M2 receptor dysfunction. Anakinra did not change smooth muscle M3 muscarinic receptor response to ACh, lung viral loads, or blood and bronchoalveolar lavage leukocyte populations. Respiratory virus infection decreased M2 receptor mRNA expression in parasympathetic ganglia extracted from infected animals, and this was prevented by blocking IL-1β or TNF-α. Treatment of SK-N-SH neuroblastoma cells or primary cultures of guinea pig parasympathetic neurons with IL-1β directly decreased M2 receptor mRNA, and this was not synergistic with TNF-α treatment. Treating guinea pig trachea segment with TNF-α or IL-1β in vitro increased tracheal contractions in response to activation of airway nerves by electrical field stimulation. Blocking IL-1β during TNF-α treatment prevented this hyperresponsiveness. These data show that virus-induced hyperreactivity and M2 dysfunction involves IL-1β and TNF-α, likely in sequence with TNF-α causing production of IL-1β.

Local production of CCL3, CCL11, and IFN-γ correlates with disease severity in murine parainfluenza virus infection

Background

Using a murine model of parainfluenza virus infection (mPIV1 or Sendai virus; SeV), we compared the inflammatory responses to lethal and sub-lethal infections in inbred DBA/2 mice.

Methods

Mice were intranasally inoculated with either 1.6×10³ or 1.6×10⁵ infectious units (IU) of SeV or diluent control. Clinical data including daily weights, oxygen saturation, and lung function via whole body plethysmography were collected on days 0, 3–7, and 9–14. Clarified whole lung homogenates were evaluated for inflammatory markers by enzyme-linked immunoassay (ELISA). Data were analyzed using ANOVA or Student t-tests, as appropriate.

Results

Mice inoculated with 1.6×10⁵ IU of SeV developed a lethal infection with 100% mortality by day 7, while mice inoculated with 1.6×10³ IU developed a clinically significant infection, with universal weight loss but only 32% mortality. Interestingly, peak virus recovery from the lungs of mice inoculated with 1.6×10⁵ IU of SeV did not differ substantially from that detected in mice that received the 100-fold lower inoculum. In contrast, concentrations of CCL5 (RANTES), CCL11 (eotaxin), interferon-γ, CXCL10 (IP-10), and CCL3 (MIP-1α) were significantly higher in lung tissue homogenates from mice inoculated with 1.6×10⁵ IU (p < 0.05). In the lethal infection, levels of CCL11, interferon- γ and CCL3 all correlated strongly with disease severity.

Conclusion

We observed that severity of SeV-infection in DBA/2 mice was not associated with virus recovery but rather with the levels of proinflammatory cytokines, specifically CCL11, interferon- γ and CCL3, detected in lung tissue in response to SeV infection.

NLRC5 knockdown in chicken macrophages alters response to LPS and poly (I:C) stimulation

Background

NLRC5 is a member of the CARD domain containing, nucleotide-binding oligomerization (NOD)-like receptor (NLR) family, which recognizes pathogen-associated molecular patterns (PAMPs) and initiates an innate immune response leading to inflammation and/or cell death. However, the specific role of NLRC5 as a modulator of the inflammatory immune response remains controversial. It has been reported to be a mediator of type I IFNs, NF-kB, and MHC class I gene. But no study on NLRC5 function has been reported to date in chickens. In the current study, we investigated the role of NLRC5 in the regulation of IFNA, IFNB, IL-6, and MHC class I in the chicken HD11 macrophage cell line, by using RNAi technology. HD11 cells were transfected with one of five siRNAs (s1, s2, s3, negative-siRNA, or a mixture of s1, s2, s3-siRNAs). After 24 hours, cells were exposed to LPS or poly (I:C) or a vehicle control. Gene expression of NLRC5, IFNA, IFNB, IL-6, and MHC class I at 2, 4, 6, and 8 hours post stimulation (hps) was quantified by qPCR.

Results

The expression of NLRC5, IFNA, IFNB, and IL-6 genes in negative irrelevant transfection controls was up-regulated at 2 hps after LPS treatment compared to the vehicle controls. S3-siRNA effectively knocked down NLRC5 expression at 4 hps, and the expression of IFNA and IFNB (but not IL-6 and MHC class I) was also down-regulated at 4 hps in s3-siRNA transfected cells, compared to negative irrelevant transfection controls. Stimulation by LPS appeared to relatively restore the decrease in NLRC5, IFNA, and IFNB expression, but the difference is not significant.

Conclusions

Functional characterization of chicken NLRC5 in an in vitro system demonstrated its importance in regulating intracellular molecules involved in inflammatory response. The knockdown of NLRC5 expression negatively mediates gene expression of IFNA and IFNB in the chicken HD11 cell line; therefore, NLRC5 likely has a role in positive regulation of IFNA and IFNB expression. No direct relationship was found between NLRC5 knockdown and IL-6 and MHC class I expression. Future studies will further clarify the roles of NLRC5 and other NLRs in infectious diseases of chickens and may increase the efficacy of antiviral vaccine design.

Development of defective and persistent Sendai virus vector: a unique gene delivery/expression system ideal for cell reprogramming

The ectopic expression of transcription factors can reprogram differentiated tissue cells into induced pluripotent stem cells. However, this is a slow and inefficient process, depending on the simultaneous delivery of multiple genes encoding essential reprogramming factors and on their sustained expression in target cells. Moreover, once cell reprogramming is accomplished, these exogenous reprogramming factors should be replaced with their endogenous counterparts for establishing autoregulated pluripotency. Complete and designed removal of the exogenous genes from the reprogrammed cells would be an ideal option for satisfying this latter requisite as well as for minimizing the risk of malignant cell transformation. However, no single gene delivery/expression system has ever been equipped with these contradictory characteristics. Here we report the development of a novel replication-defective and persistent Sendai virus (SeVdp) vector based on a noncytopathic variant virus, which fulfills all of these requirements for cell reprogramming. The SeVdp vector could accommodate up to four exogenous genes, deliver them efficiently into various mammalian cells (including primary tissue cells and human hematopoietic stem cells) and express them stably in the cytoplasm at a prefixed balance. Furthermore, interfering with viral transcription/replication using siRNA could erase the genomic RNA of SeVdp vector from the target cells quickly and thoroughly. A SeVdp vector installed with Oct4/Sox2/Klf4/c-Myc could reprogram mouse primary fibroblasts quite efficiently; ∼1% of the cells were reprogrammed to Nanog-positive induced pluripotent stem cells without chromosomal gene integration. Thus, this SeVdp vector has potential as a tool for advanced cell reprogramming and for stem cell research.

A role for the human nucleotide-binding domain, leucine-rich repeat-containing family member NLRC5 in antiviral responses

Proteins of the nucleotide-binding domain, leucine-rich repeat (NLR)-containing family recently gained attention as important components of the innate immune system. Although over 20 of these proteins are present in humans, only a few members including the cytosolic pattern recognition receptors NOD1, NOD2, and NLRP3 have been analyzed extensively. These NLRs were shown to be pivotal for mounting innate immune response toward microbial invasion. Here we report on the characterization of human NLRC5 and provide evidence that this NLR has a function in innate immune responses. We found that NLRC5 is a cytosolic protein expressed predominantly in hematopoetic cells. NLRC5 mRNA and protein expression was inducible by the double-stranded RNA analog poly(I.C) and Sendai virus. Overexpression of NLRC5 failed to trigger inflammatory responses such as the NF-kappaB or interferon pathways in HEK293T cells. However, knockdown of endogenous NLRC5 reduced Sendai virus- and poly(I.C)-mediated type I interferon pathway-dependent responses in THP-1 cells and human primary dermal fibroblasts. Taken together, this defines a function for NLRC5 in anti-viral innate immune responses.

The role of interleukin-1beta and platelet-derived growth factor-AB in antifibrosis mediated by native human interferon alpha

BACKGROUND

Commercial preparations of native human interferon alpha (nHuIFN-alpha) contain several subtypes of interferon-alpha (IFN-alpha) and traces of other cytokines. Recently, we described its antifibrotic potential and showed nHuIFN-alpha to have a greater effect than that of recombinant human IFN-alpha (rHuIFN-alpha). We hypothesized that cooperation between different cytokines in the nHuIFN-alpha preparation is essential for this effect. Considerable concentrations of interleukin-1beta (IL-1beta) and platelet-derived growth factor AB (PDGF-AB) are present in the nHuIFN-alpha preparations.

METHODS

We tested the viability and the expression of procollagen type I messenger RNA (mRNA) in MRC5 fibroblasts treated with interleukin-1 beta (IL-1beta) and/or PDGF-AB, or the corresponding antibodies in combination with rHuIFN-alpha or nHuIFN-alpha.

RESULTS

We showed that neither IL-1beta nor PDGF-AB significantly affect the viability of MRC5 cells. Furthermore, cell viability was not affected when IL-1beta or PDGF-AB were applied along with rHuIFN-alpha, relative to the viability of cells treated with rHuIFN-alpha only. In contrast, both cytokines suppressed the synthesis of procollagen type I mRNA. When coadministered with rHuIFN-alpha, IL-1beta enhanced the suppression induced by rHuIFN-alpha. Conversely, PDGF-AB acted as an antagonist of rHuIFN-alpha and restored partially the synthesis of procollagen type I mRNA. Interestingly, the addition of IL-1beta to the PDGF-AB/rHuIFN-alpha mix not only abolished the antagonistic activity of PDGF-AB but also decreased the synthesis of procollagen type I mRNA beyond the level achieved by IL-1beta/rHuIFN-alpha. Therefore, IL-1beta was able to reverse the activity of PDGF-AB.

CONCLUSION

Our study suggests that IL-1beta is an important component of nHuIFN-alpha preparations, acting directly and indirectly to modulate the action of other components. This study provides insight into these complex cytokine networks, which is necessary for better and safer antifibrotic therapy.

Pharmacokinetic-pharmacodynamic modeling of alpha interferon response induced by a Toll-like 7 receptor agonist in mice

Recombinant alpha interferon (IFN-alpha) is used in the treatment of hepatitis C virus (HCV)-infected patients but is not optimal in terms of efficacy or tolerability. Toll-like 7 receptor (TLR-7) agonists stimulate the innate immune system to produce, among other cytokines, IFN-alpha and are being evaluated as alternative drugs to treat HCV infection. This paper describes the application of pharmacokinetic-pharmacodynamic (PK-PD) modeling to understanding the behavior of a TLR-7 agonist [9-benzyl-8-hydroxy-2-(2-methoxyethoxy) adenine (BHMA)] in mice, using IFN-alpha as a biomarker. This is the first report of such a PK-PD model, and the conclusions may be of utility in the clinical development of TLR-7 agonists for HCV infection.

Newly-developed Sendai virus vector for retinal gene transfer: reduction of innate immune response via deletion of all envelope-related genes

BACKGROUND

Recombinant Sendai virus vectors (rSeV) constitute a new class of cytoplasmic RNA vectors that have shown efficient gene transfer in various organs, including retinal tissue; however, the related immune responses remain to be overcome in view of clinical applications. We recently developed a novel rSeV from which all envelope-related genes were deleted (rSeV/dFdMdHN) and, in the present study, assess host immune responses following retinal gene transfer.

METHODS

rSeV/dFdMdHN or conventional F-gene deleted rSeV (rSeV/dF) was injected into subretinal space of adult Wistar rats or C57BL/6 mice. The transgene expression and histopathological findings were assessed at various time points. Immunological assessments, including the expression of proinflammatory cytokines, natural killer (NK)-cell activity, as well as SeV-specific cytotoxic T lymphocytes (CTLs) and antibodies, were performed following vector injection.

RESULTS

rSeV/dFdMdHN showed high gene transfer efficiency into the retinal pigment epithelium at an equivalent level to that seen with rSeV/dF. In the early phase, the upregulation of proinflammatory cytokines, local inflammatory cell infiltration and tissue damage that were all prominently seen in rSeV/dF injection were dramatically diminished using rSeV/dFdMdHN. NK cell activity was also decreased, indicating a reduction of the innate immune response. In the later phase, on the other hand, CTL activity and anti-SeV antibodies were similarly induced, even using rSeV/dFdMdHN, and resulted in transient transgene expression in both vector types.

CONCLUSIONS

Deletion of envelope-related genes of rSeV dramatically reduces the vector-induced retinal damage and may extend the utility for ocular gene transfer; however, further studies regulating the acquired immune response are required to achieve long-term transgene expression of rSeV.

TNF-alpha and IFN-alpha enhance influenza-A-virus-induced chemokine gene expression in human A549 lung epithelial cells

Lung epithelial cells are the primary cellular targets for respiratory virus pathogens such as influenza and parainfluenza viruses. Here, we have analyzed influenza A, influenza B and Sendai virus-induced chemokine response in human A549 lung epithelial cells. Influenza virus infection resulted in low CCL2/MCP-1, CCL5/RANTES, CXCL8/IL-8 and CXCL10/IP-10 production at late times of infection. However, when cells were pretreated with TNF-alpha or IFN-alpha, influenza-A-virus-induced chemokine production was greatly enhanced. Cytokine pretreatment resulted in enhanced expression of RIG-I, IKKepsilon, interferon regulatory factor (IRF)1, IRF7 and p50 proteins. Most importantly, influenza-A-virus-induced DNA binding of IRF1, IRF3, IRF7 and NF-kappaB onto CXCL10 ISRE and NF-kappaB elements, respectively, was markedly enhanced in cytokine-pretreated cells. Our results suggest that IFN-alpha and TNF-alpha have a significant role in priming epithelial cells for higher cytokine and chemokine production in influenza A virus infection.

Nonstructural proteins 4A and 4B of hepatitis C virus transactivate the interleukin 8 promoter

Interleukin 8 (IL-8) is induced in many cell types by various stimuli including virus infection. It was reported that nonstructural protein 5A (NS5A) of hepatitis C virus (HCV) was involved in induction of IL-8 expression at both mRNA and protein levels in cultured human cells. In this study, we aimed to determine whether or not another HCV protein(s) transactivates the IL-8 gene expression, by means of an IL-8 promoter-driven luciferase reporter assay and measurement of endogenous IL-8 mRNA and secreted IL-8 protein levels. We observed that NS4B, and NS4A to a lesser extent, significantly transactivated the IL-8 promoter, which resulted in enhanced production of IL-8 protein. Also, the IL-8 expression was augmented in Huh-7 cells harboring an HCV subgenomic RNA replicon, compared with the control cells. Deletion mutational analysis of the IL-8 promoter revealed the possible involvement of the transcription factor AP-1 in both NS4A- and NS4B-mediated IL-8 gene activation. In addition, the IL-8 gene activation by NS4B, but not that by NS4A, was likely to involve NF-kappaB and/or NFIL-6. The degree of the transactivation by NS4B and NS4A varied with different human cell lines, with HeLa cells showing the strongest activation followed by Huh-7 cells, and with HepG2 cells exhibiting a marginal level of activation. Taken together, our present results suggest the possibility that NS4B and NS4A play an important role in inducing the IL-8 gene expression under certain cellular conditions, which might be one of the strategies to establish persistent HCV infection.

Role of macrophages in virus-induced airway hyperresponsiveness and neuronal M2 muscarinic receptor dysfunction

Viral infections exacerbate asthma. One of the pathways by which viruses trigger bronchoconstriction and hyperresponsiveness is by causing dysfunction of inhibitory M(2) muscarinic receptors on the airway parasympathetic nerves. These receptors normally limit acetylcholine (ACh) release from the parasympathetic nerves. Loss of M(2) receptor function increases ACh release, thereby increasing vagally mediated bronchoconstriction. Because viral infection causes an influx of macrophages into the lungs, we tested the role of macrophages in virus-induced airway hyperresponsiveness and M(2) receptor dysfunction. Guinea pigs infected with parainfluenza virus were hyperresponsive to electrical stimulation of the vagus nerves but not to intravenous ACh, indicating that hyperresponsiveness was due to increased release of ACh from the nerves. In addition, the muscarinic agonist pilocarpine no longer inhibited vagally induced bronchoconstriction, indicating M(2) receptor dysfunction. Treating animals with liposome-encapsulated dichloromethylene-diphosphonate depleted macrophages as assessed histologically. In these animals, viral infection did not cause airway hyperresponsiveness or M(2) receptor dysfunction. These data suggest that macrophages mediate virus-induced M(2) receptor dysfunction and airway hyperresponsiveness.

Parainfluenza viruses

Human parainfluenza viruses (HPIV) were first discovered in the late 1950s. Over the last decade, considerable knowledge about their molecular structure and function has been accumulated. This has led to significant changes in both the nomenclature and taxonomic relationships of these viruses. HPIV is genetically and antigenically divided into types 1 to 4. Further major subtypes of HPIV-4 (A and B) and subgroups/genotypes of HPIV-1 and HPIV-3 have been described. HPIV-1 to HPIV-3 are major causes of lower respiratory infections in infants, young children, the immunocompromised, the chronically ill, and the elderly. Each subtype can cause somewhat unique clinical diseases in different hosts. HPIV are enveloped and of medium size (150 to 250 nm), and their RNA genome is in the negative sense. These viruses belong to the Paramyxoviridae family, one of the largest and most rapidly growing groups of viruses causing significant human and veterinary disease. HPIV are closely related to recently discovered megamyxoviruses (Hendra and Nipah viruses) and metapneumovirus.

Recombinant Sendai virus-mediated gene transfer into adult rat retinal tissue: efficient gene transfer by brief exposure

To determine the usefulness of recombinant Sendai virus (SeV) for ocular gene transfer, the authors characterized SeV-mediated gene transfer to the retinal tissue of adult rats via subretinal injection. Recombinant SeV encoding the lacZ gene achieved frequent transgene expression in the retinal pigment epithelium (RPE) (mean=38.76%), while gene transfer to other retinal cells was rare. These findings are similar to those of previous reports using adenoviruses. Peak reporter gene expression of SeV in cultured RPE cells was similar to that of adenovirus at the same titer; however, SeV achieved high levels of expression after a brief vector-cell contact time, while adenovirus required over 3hr for efficient gene transfer. This finding was also observed in vivo following a brief SeV filling in the subretinal space, and may therefore provide a clinical advantage in avoiding retinal damage due to prolonged detachment. The observed SeV-mediated gene expression in the rat retina was transient. The initial phase of the decrease in luciferase activity could be prevented by daily eye drops of dexamethasone, suggesting that the corticosteroid-sensitive host reaction may affect early clearance of the virus. The late decline of transgene expression (2 weeks) was inhibited by the immunosuppressant, cyclosporin A, in a dose-dependent manner, suggesting that the cytotoxic T-lymphocyte response may be important in this phase. This work represents the first report of SeV-mediated gene transfer to ocular tissue, and identifies recombinant SeV as a new tool for studies of retinal gene transfer and gene therapy.

Influenza A and sendai viruses induce differential chemokine gene expression and transcription factor activation in human macrophages

Chemokines regulate leukocyte traffic and extravasation into the site of inflammation. Here we show that influenza A- or Sendai virus-infected human macrophages produce MIP-1alpha, MIP-1beta, RANTES, MCP-1, MCP-3, MIP-3alpha, IP-10, and IL-8, whereas no upregulation of MIP-3beta, eotaxin, or MDC production was detected. Influenza A virus was a better inducer of MCP-1 and MCP-3 production than Sendai virus, whereas MIP-1alpha, MIP-1beta, RANTES, MIP-3alpha, and IL-8 were induced preferentially by Sendai virus. Infection in the presence of protein synthesis inhibitor indicated that ongoing protein synthesis was required for influenza A virus-induced expression of MCP-1, MCP-3, and IP-10 genes, whereas Sendai virus-induced chemokine mRNA expression took place in the absence of de novo protein synthesis. Neutralization of virus-induced IFN-alpha/beta resulted in downregulation of virus-induced IP-10, MCP-1, and MCP-3 mRNA expression. IFN-alpha or IFN-gamma were found to directly enhance MCP-1, MCP-3, and IP-10 mRNA expression. Both influenza A and Sendai viruses similarly activated transcription factor NF-kappaB. In contrast to NF-kappaB, IRFs and STATs, the other transcription factors involved in the regulation of chemokine gene expression, were differentially activated by these viruses. Influenza A virus more efficiently activated ISGF3 complex formation and Stat1 DNA-binding compared to Sendai virus, which in turn was a more potent activator of IRF-1. Our results show that during viral infections macrophages predominantly produce monocyte and Th1 cell attracting chemokines. Furthermore, virus-induced IFN-alpha/beta enhanced chemokine gene expression in macrophages emphasizing the role of IFN-alpha/beta in the development of Th1 immune responses.

Interleukin-6 production by endothelial cells after infection with influenza virus and cytomegalovirus

Inflammation plays a role in the pathogenesis of cardiovascular diseases. Viruses may be a cause of chronic inflammation, and both influenza virus and CMV have been associated with cardiovascular diseases. IL-6, a proinflammatory cytokine with antiviral effects, has a pivotal role in the immune response, and under pathologic conditions, prohemostatic effects of IL-6 could lead to pathologic thrombosis and vascular plaque instability. To investigate this role of IL-6, we measured the production of IL-6 by human endothelial cells after infection with influenza virus and CMV. After infection with influenza virus or CMV, IL-6 release into the medium increased (1756.5+/-156.9 pg/mL vs 284.4+/-55.3 pg/mL; P < .001) for influenza-Infected compared with uninfected cells after 36 hours' incubation. Ultracentrifuged influenza virus supernatants, heat-inactivated virus, and purified hemagglutinin were not able to elicit IL-6 synthesis by human endothelial cells. These findings show that CMV and influenza virus are capable of modulating the in vitro production of IL-6, a cytokine involved in vascular inflammation, by human endothelial cells.

Biological properties of interferon-alpha produced Ex vivo by whole blood of patients infected by human immunodeficiency virus-1

We investigated the biological properties of interferon (IFN)-alpha produced by Sendai virus (SV)-activated whole blood cultures in 20 patients infected with human immunodeficiency virus (HIV)-1 and 24 healthy controls. Supernatants of cultures were assayed for IFN-alpha by using an immunological method (DELFIA), biological methods and an in-vitro MxA induction assay. The levels of intracellular MxA protein were detected by an immunochemiluminescence assay. The levels of IFN-alpha in patients measured by DELFIA were significantly lower than those in healthy controls (P < 0.0001), but the antiviral activity of IFN-alpha in patients infected with HIV-1 was lower than predicted from DELFIA. The IFN-alpha produced by cells of patients infected with HIV-1 was able to induce MxA protein in human amnions WISH cells but was unable to protect these cells against Vesicular Stomatitis Virus (VSV)-induced cytopathic effects. A relative increased capability to induce the production of MxA protein in vitro was observed with the IFN-alpha contained in culture supernatant of virus-activated whole blood of HIV-1-infected patients with increased levels of MxA in their peripheral blood. These data suggest that biological properties of IFN-alpha produced in the course of HIV-1 infection are different from those observed with IFN-alpha of healthy subjects.

Natural pathogens of laboratory mice, rats, and rabbits and their effects on research

Laboratory mice, rats, and rabbits may harbor a variety of viral, bacterial, parasitic, and fungal agents. Frequently, these organisms cause no overt signs of disease. However, many of the natural pathogens of these laboratory animals may alter host physiology, rendering the host unsuitable for many experimental uses. While the number and prevalence of these pathogens have declined considerably, many still turn up in laboratory animals and represent unwanted variables in research. Investigators using mice, rats, and rabbits in biomedical experimentation should be aware of the profound effects that many of these agents can have on research.

Dynamic Regulation of α- and β-Chemokine Expression in the Central Nervous System During Mouse Hepatitis Virus-Induced Demyelinating Disease

Infection of C57BL/6 mice with the V5A13.1 strain of mouse hepatitis virus (MHV-V5A13.1) results in an acute encephalomyelitis and chronic demyelinating disease with features similar to the human demyelinating disease multiple sclerosis. Chemokines are a family of proinflammatory cytokines associated with inflammatory pathology in various diseases. The kinetics and histologic localization of chemokine production in the central nervous system of MHV-infected mice were examined to identify chemokines that contribute to inflammation and demyelination. Transcripts for the chemokines cytokine-response gene-2 (CRG-2), regulated on activation, normal T cell expressed and secreted (RANTES), macrophage-chemoattractant protein-1 and protein-3 (MCP-1, MCP-3), macrophage-inflammatory protein-1β (MIP-1β), and MIP-2 were detected in the brains of MHV-infected mice at 3 days postinfection (p.i.), and these transcripts were increased markedly in brains and spinal cords at day 7 p.i., which coincides with the occurrence of acute viral encephalomyelitis. By day 35 p.i., RANTES, CRG-2, and MIP-1β were detected in brains and spinal cords of mice with chronic demyelination. CRG-2 mRNA expression colocalized with viral RNA and was associated with demyelinating lesions. Astrocytes were the predominant cell type expressing CRG-2 mRNA. These observations suggest a role for chemokines, notably CRG-2, in the initiation and maintenance of an inflammatory response following infection with MHV, which is important in contributing to demyelination.

Identification of nine interferon-alpha subtypes produced by Sendai virus-induced human peripheral blood leucocytes

The human interferon-alpha (IFN-alpha) family is encoded by 13 different functional genes, and including all cloned sequence variants there are 28 potential IFN-alpha proteins. To find out which of the described sequences are expressed in normal human leucocytes, we have isolated and partly characterized the components of a highly purified IFN-alpha preparation produced by Sendai virus-induced human peripheral blood leucocytes. The identification protocol consisted of N-terminal sequencing and mass mapping of the proteins separated by reverse-phase HPLC and/or SDS/PAGE. The highly purified leucocyte IFN-alpha preparation was found to contain at least nine different IFN-alpha species: IFN-alpha1a, IFN-alpha2b, IFN-alpha4b, IFN-alpha7a, IFN-alpha8b, IFN-alpha10a, IFN-alpha14c, IFN-alpha17b and IFN-alpha21b. IFN-alpha1a was the major subtype, comprising approx. 30% of total leucocyte IFN-alpha. IFN-alpha14c, the only subtype containing potential N-glycosylation sites, was shown to be glycosylated at Asn-72. Molecular mass determination of the intact proteins by electrospray ionization MS showed that there are no other post-translational modifications in the IFN-alpha subtypes than the glycosylation of IFN-alpha2b and IFN-alpha14c. Only one sequence variant was found for each subtype, suggesting that the other described gene sequences represent allelic variants or mutations that are more rarely found in the general population.

Chemoattractant factors (IP-10, MIP-1alpha, IL-16) mRNA expression in mononuclear cells from different tissues during acute SIVmac251 infection of macaques

We have used semiquantitative RT-PCR to monitor the expression of mRNA encoding chemoattractant factors IP-10, MIP-1alpha, and IL-16 in freshly isolated peripheral blood mononuclear cells (PBMCs), lymph node mononuclear cells (LNMCs), and mononuclear cells obtained after bronchoalveolar lavages (BALMCs) of two cynomolgus macaques inoculated intravenously with a pathogenic isolate of simian immunodeficiency virus, SIVmac251. Concomitant with the peak of systemic viral replication (two weeks after experimental inoculation) and proinflammatory cytokine IL-6 mRNA expression, high levels of MIP-1alpha and IP-10 mRNA were produced in LNMCs and BALMCs. In BALMCs, in which we have reported a marked progressive overexpression of IFN-gamma mRNA coinciding with an increase in the CD8+ lymphocyte percentages, we noticed a progressive overexpression of IL-16 mRNA. Our results suggest the role of chemokines IP-10, MIP-1alpha, and IL-16 in the development of inflammatory and immune responses during the early stages of lentiviral infection.