Contribution of classic and alternative effector pathways in peanut-induced anaphylactic responses

Food allergy affects approximately 5% of children and is the leading cause of hospitalization for anaphylactic reactions in westernized countries. However, the pathways of anaphylaxis in food allergy are still relatively unknown. We investigated the effector pathways of allergic and anaphylactic responses of different strains of mice in a clinical relevant model of peanut allergy. C3H/HeOuJ, C57BL/6 and BALB/c mice were sensitized by intragastric peanut extract and challenged by intragastric or intraperitoneal injection of peanut. Peanut-specific T cell responses, IgE, IgG1 and IgG2a and mucosal mast cell degranulation were induced to different extent in C3H/HeOuJ, C57BL/6 and BALB/c mice. Interestingly, anaphylactic symptoms after systemic challenge were highest in C3H/HeOuJ followed by C57BL/6 but were absent in BALB/c mice. Mechanistic studies showed that the food allergic systemic anaphylaxis was dependent on platelets, FcRγ and mast cells, and partially dependent on platelet activating factor and monocytes/macrophages, depending on mouse strain. These data demonstrate that in three mouse strains, components of the classic and alternative anaphylactic cascade are differently expressed, leading to differential outcomes in parameters of allergic disease and food induced systemic anaphylaxis.     

Dietary unripe apple polyphenol inhibits the development of food allergies in murine models

The incidence of type I allergic disorders has been increasing worldwide, particularly, the hypersensitivity to food. We first showed that apple condensed tannin (ACT) intake would inhibit the development of the oral sensitization and that the inhibition could correlate with the rise in the population of TCR(gamma)delta-T cells in the intestinal intraepithelial lymphocytes (IEL) using W/W(V) mice and B10A mice which were ovalbumin (OVA)-orally sensitized. Serum OVA-specific immunoglobulin E and immunoglobulin G1 titers in the OVA-orally sensitized W/W(V) and B10A mice ad libitium fed ACT were extremely inhibited compared to those of the control. The ACT intakes of OVA-sensitized W/W(V) and B10A mice inhibited the immediate reduction of the body temperature or the rise in serum histamine induced by active systemic anaphylaxis. The proportions of the TCR(gamma)delta-T cells in the IEL of the OVA-orally sensitized W/W(V) and B10A mice ad libitium fed ACT were significantly greater than that in the controls. Furthermore, ACT feeding by itself could induce the rise in the percentage of the TCR(gamma)delta-T cells among the IEL of the W/W(V) and B10A mice. This suggests that the ACT intake may prevent the development of food allergies and this effect could be correlated with the rise in the percentage of TCR(gamma)delta-T cells among the IEL.     

Expression of toll-like receptor 2 on gamma delta T cells bearing invariant V gamma 6/V delta 1 induced by Escherichia coli infection in mice

We recently reported that the number of gamma delta T cells was increased after infection with Escherichia coli in C3H/HeN mice. We here showed that an i.p. injection with native lipid A derived from E. coli induced an increase of gamma delta T cells in the peritoneal cavity of LPS-responsive C3H/HeN mice and, albeit to a lesser degree, also in LPS-hyporesponsive C3H/HeJ mice. The purified gamma delta T cells from C3H/HeN and C3H/HeJ mice expressed a canonical TCR repertoire encoded by V gamma 6-J gamma 1/V delta 1-D delta 2-J delta 2 gene segments and proliferated in response to the native lipid A derived from E. coli in a TCR-independent manner. The lipid A-reactive gamma delta T cells bearing canonical V gamma 6/V delta 1 expressed Toll-like receptor (TLR) 2 mRNA, while TLR4 mRNA was undetectable. Treatment with a TLR2 anti-sense oligonucleotide resulted in hyporesponsiveness of the gamma delta T cells to the native lipid A. TLR2-deficient mice showed an impaired increase of the gamma delta T cells following injection of native lipid A. These results suggest that TLR2 is involved in the activation of canonical V gamma 6/V delta 1 T cells by native E. coli lipid A.     

IL-9 promotes but is not necessary for systemic anaphylaxis

Anaphylaxis represents an extreme form of allergic reaction, consisting of a sensitization phase during which allergen-specific IgE are produced and an acute effector phase triggered by allergen-induced degranulation of mast cells. We studied the role of IL-9, a Th2 cytokine implicated in asthma, in different models of murine anaphylaxis. Using a passive model of systemic anaphylaxis, in which anti-DNP IgE Abs were administered before challenge with DNP-BSA, we found that IL-9-transgenic mice or wild-type mice treated with IL-9 for 5 days were highly sensitive to fatal anaphylaxis. This effect was reproduced in both anaphylaxis-susceptible and -resistant backgrounds (FVB/N or [FVB/N x BALB/c] F(1) mice, respectively) and correlated with increased serum concentrations of mouse mast cell protease-1 level, a protein released upon mast cells degranulation. By contrast, IL-9 did not increase the susceptibility to passive cutaneous anaphylaxis. IL-9 expression also increased the susceptibility to fatal anaphylaxis when mice were sensitized by immunization against OVA before challenge with the same Ag. In this model, serum from sensitized, IL-9-transgenic mice was more potent in transferring susceptibility to OVA challenge into naive mice, indicating that IL-9 also promotes the sensitization stage. Finally, using IL-9R-deficient mice, we found that despite its anaphylaxis-promoting activity, IL-9 is dispensable for development of both passive and active anaphylaxis, at least in the C57BL/6 mouse background. Taken together, the data reported in this study indicate that IL-9 promotes systemic anaphylaxis reactions, acting at both the sensitization and effector stages, but is not absolutely required for this process.     

Influence of glucocorticoids on time-of-day-dependent variations in IgE-, histamine-, and platelet-activating factor-mediated systemic anaphylaxis in different mouse strains

A time-of-day-dependent variation in IgE-mediated passive systemic anaphylaxis was previously reported in ICR mice. In the present study, we investigated time-of-day-dependent variations in IgE-, histamine-, and platelet-activating factor (PAF)-mediated systemic anaphylaxis in C57BL/6, BALB/c, and NC/Nga mice at 9:00?h and 21:00?h, and evaluated the potential influence of glucocorticoids (GCs) on these variations. We found significant time-of-day-dependent variations in IgE-mediated systemic anaphylaxis in C57BL/6 mice, and in histamine- and PAF-mediated systemic anaphylaxis in BALB/c mice. Significant daily variations in IgE-, histamine-, and PAF-mediated systemic anaphylaxis were not observed in NC/Nga mice. Pretreatment with dexamethasone and adrenalectomy abolished the daily variations in IgE-mediated systemic anaphylaxis in C57BL/6 mice and in PAF-mediated systemic anaphylaxis in BALB/c mice, suggesting that GCs from adrenal glands are pivotal in regulating these variations. In contrast, pretreatment with dexamethasone and adrenalectomy did not abolish the daily variation in histamine-mediated systemic anaphylaxis in BALB/c mice, suggesting that GC-independent and adrenal gland-independent mechanisms are important for the variation. The present study demonstrated that time-of-day-dependent variations in systemic anaphylaxis differed among inbred mouse strains and with anaphylaxis-inducing substances. Thus, mouse strains, time of experiment, and anaphylaxis-inducing substances used must be considered to obtain appropriate experimental results.     

The roles of mast cells and Kupffer cells in rat systemic anaphylaxis

Mast cells and other cells such as macrophages have been shown to mediate systemic anaphylaxis. We determined the roles of mast cells and Kupffer cells in hepatic and systemic anaphylaxis of rats. Roles of mast cells were examined by using the mast cell-deficient white spotting (Ws/Ws) rat; the Ws/Ws and wild type (+/+) rats were sensitized with ovalbumin (1 mg). Roles of Kupffer cells were examined by depleting Kupffer cells using gadolinium chloride or liposome-encapsulated dichloromethylene diphosphonate in the Ws/Ws and Sprague-Dawley rats. An intravenous injection of 0.6 mg ovalbumin caused substantial anaphylactic hypotension in both the Ws/Ws and +/+ rats; however, the occurrence was delayed in the Ws/Ws rats. After antigen, portal venous pressure increased by 13.1 cmH2O in the +/+ rats, while it increased only by 5.7 cmH2O in the Ws/Ws rats. In response to antigen, the isolated perfused liver of the Ws/Ws rats also showed weak venoconstriction, the magnitude of which was one tenth as large as that of the +/+ rats, indicating that hepatic anaphylaxis was primarily due to mast cells. In contrast, Kupffer cell depletion did not attenuate anaphylactic hepatic venoconstriction in isolated perfused livers. In conclusion, mast cells are involved mainly in anaphylactic hepatic presinusoidal portal venoconstriction but only in the early stage of anaphylactic systemic hypotension in rats. Macrophages, including Kupffer cells, do not participate in rat hepatic anaphylactic venoconstriction.     

Modifications by BCG of the mortality of the irradiated mouse]

Freeze-dried Bacillus Calmette Guerin (B.C.G.) of Institut Pasteur was given by intravenous route to mice at 1,2 and 4 mg/kg before and after gamma irradiation of animals by 1 000 rad. B.C.G. 1 mg/kg injected the day or the day after irradiation has a protective effect (mortality reduced from 77% for controls to 58% and 50% for treated mice). B.C.G. given before irradiation in single or double doses increased mortality.     

Induction of histiocytic sarcoma in mouse skeletal muscle

Myeloid sarcomas are extramedullary accumulations of immature myeloid cells that may present with or without evidence of pathologic involvement of the bone marrow or peripheral blood, and often coincide with or precede a diagnosis of acute myeloid leukemia (AML). A dearth of experimental models has hampered the study of myeloid sarcomas and led us to establish a new system in which tumor induction can be evaluated in an easily accessible non-hematopoietic tissue compartment. Using ex-vivo transduction of oncogenic Kras(G12V) into p16/p19(-/-) bone marrow cells, we generated transplantable leukemia-initiating cells that rapidly induced tumor formation in the skeletal muscle of immunocompromised NOD.SCID mice. In this model, murine histiocytic sarcomas, equivalent to human myeloid sarcomas, emerged at the injection site 30-50 days after cell implantation and consisted of tightly packed monotypic cells that were CD48+, CD47+ and Mac1+, with low or absent expression of other hematopoietic lineage markers. Tumor cells also infiltrated the bone marrow, spleen and other non-hematopoietic organs of tumor-bearing animals, leading to systemic illness (leukemia) within two weeks of tumor detection. P16/p19(-/-); Kras(G12V) myeloid sarcomas were multi-clonal, with dominant clones selected during secondary transplantation. The systemic leukemic phenotypes exhibited by histiocytic sarcoma-bearing mice were nearly identical to those of animals in which leukemia was introduced by intravenous transplantation of the same donor cells. Moreover, murine histiocytic sarcoma could be similarly induced by intramuscular injection of MLL-AF9 leukemia cells. This study establishes a novel, transplantable model of murine histiocytic/myeloid sarcoma that recapitulates the natural progression of these malignancies to systemic disease and indicates a cell autonomous leukemogenic mechanism.     

High level expression of the plasma cell antigen PC.1 on the T-cell subset expanding in MRL/MpJ-lpr/lpr mice: detection with a xenogeneic monoclonal antibody and alloantisera

MRL/MpJ-lpr/lpr (MRL-lpr/lpr) mice spontaneously develop a systemic lupus erythematosus-like syndrome associated with the expansion of a T-cell subset exerting helper activity for autoantibody production. Several studies have demonstrated that these T cells have unusual phenotypic characteristics including the expression of the B220 B-cell marker. To further characterize the antigenic profiles of these T cells, we have generated monoclonal antibodies (MAb) by immunizing rats with MRL-lpr/lpr T cells. Using flow cytofluorometry analysis, one of these MAb (4G6), described here, was found to react strongly with T cells of MRL-lpr/lpr mice but weakly with T cells of congenic mice lacking the lpr mutation (MRL/MpJ-+/+ mice). This MAb also stained brightly T cells from C3H/Hej-lpr/lpr mice and dimly those from normal C3H/Hej mice. However, it failed to react with T cells from C57Bl/6-lpr/lpr mice or normal C57Bl/6 (B6) mice. Analysis of 4G6 reactivity (weak vs negative) of T cells in a series of inbred strains demonstrated a correlation with the Pca-1a genotype known to result in expression of the PC.1 antigen on plasma cells. Immunoprecipitation studies revealed that the 4G6 antigen has a mean apparent molecular weight of 115,000, under reducing conditions, similar to that of PC.1. Moreover, high expression of 4G6 was found on plasmacytoma lines and B blasts but not on T blasts. Identity of the 4G6 antigen with PC.1 was confirmed by the finding that conventional anti-PC.1 alloantisera could block the cell surface binding of the 4G6 MAb. Therefore, T cells from MRL-lpr/lpr (and C3H-lpr/lpr) mice aberrantly carry high levels of a plasma cell antigen, detected by the 4G6 MAb, which substantiates further that these T cells represent a unique subset with some surface properties of the B-cell lineage.     

IgG-mediated systemic anaphylaxis to protein antigen can be induced even under conditions of limited amounts of antibody and antigen

Systemic anaphylaxis is an acute, severe, and potentially fatal allergic reaction. Two classes of antibodies, IgE and IgG, contribute to the development of anaphylaxis in mice, through different mechanisms with distinct usage of effector cells and chemical mediators. Larger quantities of antibody and antigen are reportedly required to induce IgG-mediated anaphylaxis than IgE-mediated one, suggesting that the former may not happen as frequently as the latter in real life. To readdress this issue, we established in the present study a novel mouse model of passive IgG-mediated systemic anaphylaxis to a native protein antigen, ovalbumin (OVA), rather than artificially haptenated protein antigens used in previous studies. Passive sensitization of mice with a cocktail of but not individual IgG1 mAbs specific to distinct OVA epitopes elicited systemic anaphylaxis in response to OVA challenge. Importantly, much smaller doses of antibody and antigen than previously reported were sufficient for the induction of IgG-mediated systemic anaphylaxis. Moreover, a relatively small dose of antigen could induce severe anaphylaxis through both IgE- and IgG-mediated mechanisms when mice had been passively sensitized with antigen-specific IgE and IgG. These results strongly suggest that IgG-mediated systemic anaphylaxis is not rare among antibody-mediated systemic anaphylaxis, in contrast to previous thought, and significantly contributes to active systemic anaphylaxis in real life, at least in mice.     

The cellular basis for immune interferon production in autoimmune MRL-Ipr/Ipr mice

Disturbances in immune interferon (IFN gamma) activity have been implicated in the development of human systemic lupus erythematosus (SLE) and the spontaneous disease sustained by autoimmune-prone mice. We therefore investigated the cellular basis for IFN gamma production in MRL-Ipr/Ipr mice and examined the relationship between synthesis of interleukin 2 (IL 2) and IFN gamma. In vitro IL 2 and IFN gamma production in 3 to 6-mo-old, autoimmune MRL-Ipr/Ipr and MRL-+/+ mice was compared with that seen in age- and sex-matched, immunologically normal CBA/J mice. 5 X 10(6) spleen cells were pulsed with 5 micrograms of concanavalin A (Con A), and the cellfree supernatant was assayed for IL 2 and IFN gamma activity at various times up to 72 hr. We found that peak levels of IL 2 in MRL mice were less than 10% of those in the CBA/J. Yet, production of IFN gamma by cells from the autoimmune and normal strains was quite comparable. The addition of murine IL 2 to optimally Con A-stimulated cells from the MRL-Ipr/Ipr or normal mice did not affect the subsequent peak production of IFN gamma. Although the primary producers of IFN gamma in cultures of normal mice bear the Lyt-2+ phenotype, the Lyt-1+2- T-cell subset was found to be the principal source of IFN gamma in the aged MRL-Ipr/Ipr. These data suggest that Lyt-1+ cells from MRL-Ipr/Ipr mice may be differentially responsive to the signal delivered by the same mitogenic lectin with respect to lymphokine production and may indicate a distorted commitment of such cells toward production of IFN gamma and repression of IL 2 synthesis. The relationship between hypoproduction of IL 2, this usual source of IFN gamma, and the autoimmune disease sustained by MRL-Ipr/Ipr mice remains unclear.     

Effect of in vitro interferon treatment on the rapid clearance of murine leukemia cells in vivo.

Previous work showed that interferon (IFN) can protect target cells from NK mediated lysis in vitro. In the present study we investigate the effect of IFN alpha/beta or IFN gamma treatment of three different murine leukemia cell lines. For this purpose FLC-745 (susceptible to the antiproliferative activity of IFN alpha/beta and gamma), FLC-3C18 (IFN alpha/beta -resistant and IFN gamma - susceptible) of DBA/2 origin and EL-4 (IFN alpha/beta - susceptible and IFN gamma - resistant) leukemia of C57B1/6 origin were treated with IFN alpha/beta or gamma in vitro and assayed for their susceptibility to natural resistance measured in vivo as organ rapid clearance 4 hr after iv injection into syngeneic mice. Using young or Poly I:C stimulated hosts, but not mice with low levels of natural resistance (i.e. older animals or mice treated with cyclophosphamide), slower elimination of treated cells was observed with: (a) FLC-745 cells treated with IFN alpha/beta and IFN gamma and (b) FLC 3C18 treated with IFN gamma. Such a delayed clearance was not observed with: (a) FLC-3C18 cells treated with IFN alpha/beta and (b) EL-4 leukemia cells preincubated with IFN alpha/beta or IFN gamma. These results suggest that under selected conditions IFNs can protect leukemic cells from in vivo natural reactivity.     

A mechanism for anti-asialo GM 1 antibody-induced anaphylactoid response in mice infected with Trichinella pseudospiralis

Intravenous injection of anti-asialo GM 1 antibody into mice infected with Trichinella pseudospiralis resulted in rapid acute illness or death accompanied by a dramatic rise in hematocrit values in these animals. The described antibody-induced changes were reversible by intravenous infusion of Hanks' balanced salt solution (HBSS). These effects were not seen in uninfected mice or in Trichinella spiralis-infected mice injected with anti-asialo GM 1 antibody. Viability of T. spiralis or T. pseudospiralis infective L1 larvae, both isolated worms and those housed in muscle, was unaffected by exposure to anti-asialo GM 1 antibody and complement. Infectivity of larvae of T. pseudospiralis decreased significantly following exposure to anti-asialo GM 1 antibody. Release of protein by T. pseudospiralis infective L1 larvae during incubation in the presence of anti-asialo GM 1 antibody was significantly greater than that released by worms incubated in normal rabbit serum or HBSS. Protein released by infective L1 larvae of T. pseudospiralis was identified as Trichinella excretory/secretory antigens by immunoblot. Intravenous injection of T. pseudospiralis excretory/secretory products resulted in anaphylaxis in T. pseudospiralis-infected mice but not in uninfected or T. spiralis-infected mice. Excretory/secretory product-induced anaphylactoid response also was reversible by the intravenous injection of HBSS or by injection of an antihistamine. Significantly higher levels of total IgE were observed in sera from mice infected with T. pseudospiralis compared to uninfected or T. spiralis-infected mice. Binding of anti-asialo GM 1 antibody to the surface of T. pseudospiralis muscle larvae induced release of excretory/secretory antigen by the parasite.(ABSTRACT TRUNCATED AT 250 WORDS)     

Strain-dependent induction of allergic sensitization caused by peanut allergen DNA immunization in mice

To investigate the potential application of allergen gene immunization in the modulation of food allergy, C3H/HeSn (C3H) mice received i.m. injections of pAra h2 plasmid DNA encoding one of the major peanut allergens, Ara h2. Three weeks following pDNA immunization, serum Ara h2-specific IgG2a, IgG1, but not IgE, were increased significantly in a dose-dependent manner. IgG1 was 30-fold higher in multiply compared with singly immunized mice. Ara h2 or peanut protein injection of immunized mice induced anaphylactic reactions, which were more severe in multiply immunized mice. Heat-inactivated immune serum induced passive cutaneous anaphylaxis, suggesting that anaphylaxis in C3H mice was mediated by IgG1. IgG1 responses were also induced by intradermal injection of pAra h2, and by i.m. injection of pOMC, the plasmid DNA encoding the major egg allergen protein, ovomucoid. To elucidate whether the pDNA immunization-induced anaphylaxis was a strain-dependent phenomenon, AKR/J and BALB/c mice also received multiple i.m. pAra h2 immunizations. Injection of peanut protein into these strains at weeks 3 or 5 following immunization did not induce reactions. Although IgG2a was increased significantly from week 2 in AKR/J mice and from week 4 in BALB/c mice and remained elevated for at least 6 wk, no IgG1 or IgE was detected. These results indicate that the type of immune responses to pDNA immunization in mice is strain dependent. Consequently, models for studying human allergen gene immunization require careful selection of suitable strains. In addition, this suggests that similar interindividual variation is likely in humans.     

Anti-Candida resistance in the mouse brain and effect of intracerebral administration of interleukin 1

The effects of intracerebral and intravenous Candida albicans infection on experimental meningo-encephalitis in mice were compared. Naive mice inoculated with two C. albicans strains of different pathogenicity (highly virulent CA-6 and poorly virulent PCA-2) were more resistant to infection when the yeasts were inoculated by the intracerebral rather than the intravenous route. In immunized mice, in which systemic immunity had been induced by long-term colonization with low-virulence PCA-2 cells, increased intracerebral resistance to challenge with virulent Candida was observed at about two weeks post-infection. In contrast, the inoculation of PCA-2 cells directly into the brain resulted in early, long-lasting activation of local microbicidal mechanisms against intracerebral challenge with CA-6, Staphylococcus aureus or Aspergillus fumigatus. Increased local anti-Candida resistance was also observed upon intracerebral injection of human recombinant interleukin 1. These data suggest that, in addition to the intracerebral expression of systemic antifungal immunity, microbial mechanisms may be locally activated in the brain, possibly through release of endogenous interleukin 1.     

Helminth infection protects mice from anaphylaxis via IL-10-producing B cells

Modulation of the immune system by infection with helminth parasites, including schistosomes, is proposed to reduce the levels of allergic responses in infected individuals. In this study we investigated whether experimental infection with Schistosoma mansoni could alter the susceptibility of mice to an extreme allergic response, anaphylaxis. We formally demonstrate that S. mansoni infection protects mice from an experimental model of systemic fatal anaphylaxis. The worm stage of infection is shown to mediate this protective effect. In vivo depletion studies demonstrated an imperative role for B cells and IL-10 in worm-mediated protection. Furthermore, worm infection of mice increases the frequency of IL-10-producing B cells compared with that in uninfected mice. However, transfer of B cells from worm-infected mice or in vitro worm-modulated B cells to sensitized recipients exacerbated anaphylaxis, which was attributed to the presence of elevated levels of IL-4-producing B cells. Worm-modulated, IL-10-producing B cells from IL-4-deficient, but not IL-5-, IL-9- or IL-13-deficient, mice conferred complete resistance to anaphylaxis when transferred to naive mice. Therefore, we have dissected a novel immunomodulatory mechanism induced by S. mansoni worms that is dependent on an IL-10-producing B cell population that can protect against allergic hypersensitivity. These data support a role for helminth immune modulation in the hygiene hypothesis and further illustrate the delicate balance between parasite induction of protective regulatory (IL-10) responses and detrimental (IL-4) allergic responses.     

The Role of Lumbar Sympathetic Nerves in Regulation of Blood Flow to Skeletal Muscle during Anaphylactic Hypotension in Anesthetized Rats

During hypovolemic shock, skeletal muscle blood flow could be redistributed to vital organs via vasoconstriction in part evoked by activation of the innervating sympathetic nerve activity. However, it is not well known whether this mechanism operates during anaphylactic shock. We determined the femoral artery blood flow (FBF) and lumbar sympathetic nerve activity (LSNA) mainly regulating the hindquater muscle blood flow during anaphylactic hypotension in anesthetized rats. Anesthetized Sprague-Dawley rats were randomly allocated to the following groups (n = 7/group): (1) non-sensitized, (2) anaphylaxis, (3) anaphylaxis-lumbar sympathectomy (LS) and (4) anaphylaxis-sinoaortic denervation (SAD) groups. Anaphylaxis was induced by an intravenous injection of the ovalbumin antigen to the sensitized rats. The systemic arterial pressure (SAP), heart rate (HR), central venous pressure (CVP), FBF and LSNA were continuously measured. In the anaphylaxis group, LSNA and HR increased, while SAP and FBF decreased after antigen injection. In the anaphylaxis-SAD group, LSNA did not significantly change during the early phase, but the responses of SAP and FBF were similar to those in the anaphylaxis group. In the anaphylaxis-LS group, both FBF and SAP decreased similarly to the anaphylaxis group during anaphylactic hypotension. These results indicated that LSNA increased via baroreceptor reflex, but this sympathoexcitation or LS did not affect antigen-induced decreases in FBF or SAP. Lumbar sympathetic nerves are not involved in regulation of the blood flow to the hindlimb or systemic blood pressure during anaphylactic hypotension in anesthetized rats.     

Respiratory Syncytial Virus G and/or SH Protein Alters Th1 Cytokines, Natural Killer Cells, and Neutrophils Responding to Pulmonary Infection in BALB/c Mice

BALB/c mice sensitized to vaccinia virus expressed G protein of respiratory syncytial virus (RSV) develop a Th2-type cytokine response and pulmonary eosinophilia when challenged with live RSV. In this study, BALB/c mice were immunized or challenged with an RSV mutant lacking the G and SH proteins or with DNA vaccines coding for RSV G or F protein. F or G protein DNA vaccines were capable of sensitizing for pulmonary eosinophilia. The absence of the G and/or SH protein in the infecting virus resulted in a consistent increase both in pulmonary natural killer cells and in gamma interferon and tumor necrosis factor expression, as well as, with primary infection, a variable increase in neutrophils and CD11b(+) cells. The development of pulmonary eosinophilia in formalin-inactivated RSV-vaccinated mice required the presence of the G and/or SH protein in the challenge virus. These data show that G and/or SH protein has a marked impact on the inflammatory and innate immune response to RSV infection.     

Immune suppression in vivo with antigen-modified syngeneic cells. II. T cell-mediated nonresponsiveness to fowl gamma-globulin.

Intravenous administration of syngeneic spleen cells coupled with the palmitoyl derivative of fowl gammma-globulin (p-F gamma G) results in a profound state of F gamma G-specific tolerance in C57BL/6 mice. Administration of p-F gamma G coupled syngeneic cells specifically reduces both the primary and secondary hapten and carrier-specific PFC responses to TNP-F gamma G. Since the haptenic response is affected, the tolerance functions at the level of the F gamma G-specific helper T cell. As few as 10(3) p-F gamma G spleen cells carrying only 1 ng of p-F gamma G can induce tolerance. At least a 2-day-induction period is required. This nonresponsiveness is long lived, lasting over 120 days. Spleen cells from tolerized mice can transfer suppression to normal syngeneic recipients. Treatment of tolerant spleens with anti-Thy 1.2 antiserum + C eliminates the suppressor cell activity. In addition, thymocytes and purified splenic T cells from tolerized mice can transfer suppression to normal recipients. Thus, at least a component of this nonresponsiveness is mediated by suppressor T cells. The requirement of antigen association with cell membrane components and the general applicability of this method of inducing T cell nonresponsiveness are discussed.     

CTLA4IgG gene delivery prevents autoantibody production and lupus nephritis in MRL/lpr mice

MRL/MP-lpr/lpr (MRL/lpr) mice spontaneously develop an autoimmune syndrome closely resembling systemic lupus erythematosus (SLE) in humans, characterized by hypergammaglobulinemia, various autoantibody production, and the development of fatal glomerulonephritis. We have previously demonstrated that systemic administration of soluble form of CTLA4IgG prevented autoantibody-related diseases in MRL/lpr mice. To test the potential protective effects of CTLA4IgG gene delivery on the development of lupus nephritis, we injected MRL/lpr mice with a recombinant adenovirus vector containing CTLA4IgG gene, Adex1CACTLA4IgG (AdCTLA4IgG). It was demonstrated that a single administration of intravenous injection of AdCTLA4IgG into MRL/lpr mice resulted in almost complete amelioration of lupus nephritis.