Reduction In Footpad Swelling Research Articles

Inhibition of BET Proteins Regulates Fcγ Receptor Function and Reduces Inflammation in Rheumatoid Arthritis.

Overactivation of immune responses is a hallmark of autoimmune disease pathogenesis. This includes the heightened production of inflammatory cytokines such as Tumor Necrosis Factor α (TNFα), and the secretion of autoantibodies such as isotypes of rheumatoid factor (RF) and anticitrullinated protein antibody (ACPA). Fcγ receptors (FcγR) expressed on the surface of myeloid cells bind Immunoglobulin G (IgG) immune complexes. Recognition of autoantigen-antibody complexes by FcγR induces an inflammatory phenotype that results in tissue damage and further escalation of the inflammatory response. Bromodomain and extra-terminal protein (BET) inhibition is associated with reduced immune responses, making the BET family a potential therapeutic target for autoimmune diseases such as rheumatoid arthritis (RA). In this paper, we examined the BET inhibitor PLX51107 and its effect on regulating FcγR expression and function in RA. PLX51107 significantly downregulated expression of FcγRIIa, FcγRIIb, FcγRIIIa, and the common γ-chain, FcϵR1-γ, in both healthy donor and RA patient monocytes. Consistent with this, PLX51107 treatment attenuated signaling events downstream of FcγR activation. This was accompanied by a significant decrease in phagocytosis and TNFα production. Finally, in a collagen-induced arthritis model, PLX51107-treatment reduced FcγR expression in vivo accompanied by a significant reduction in footpad swelling. These results suggest that BET inhibition is a novel therapeutic approach that requires further exploration as a treatment for patients with RA.

Polylactide Nanoparticles as a Biodegradable Vaccine Adjuvant: A Study on Safety, Protective Immunity and Efficacy against Human Leishmaniasis Caused by Leishmania Major.

Leishmaniasis is the 3rd most challenging vector-borne disease after malaria and lymphatic filariasis. Currently, no vaccine candidate is approved or marketed against leishmaniasis due to difficulties in eliciting broad immune responses when using sub-unit vaccines. The aim of this work was the design of a particulate sub-unit vaccine for vaccination against leishmaniasis. The poly (D,L-lactide) nanoparticles (PLA-NPs) were developed in order to efficiently adsorb a recombinant L. major histone H2B (L. major H2B) and to boost its immunogenicity. Firstly, a study was focused on the production of well-formed nanoparticles by the nanoprecipitation method without using a surfactant and on the antigen adsorption process under mild conditions. The set-up preparation method permitted to obtain H2B-adsorbed nanoparticles H2B/PLA (adsorption capacity of about 2.8% (w/w)) with a narrow size distribution (287 nm) and a positive zeta potential (30.9 mV). Secondly, an in vitro release assay performed at 37 °C, pH 7.4, showed a continuous release of the adsorbed H2B for almost 21 days (30%) from day 7. The immune response of H2B/PLA was investigated and compared to H2B + CpG7909 as a standard adjuvant. The humoral response intensity (IgG) was substantially similar between both formulations. Interestingly, when challenged with the standard parasite strain (GLC94) isolated from a human lesion of cutaneous leishmaniasis, mice showed a significant reduction in footpad swelling compared to unvaccinated ones, and no deaths occurred until week 17th. Taken together, these results demonstrate that PLA-NPs represent a stable, cost-effective delivery system adjuvant for use in vaccination against leishmaniasis.

Repeated intravenous injection of adipose tissue derived mesenchymal stem cells enhances Th1 immune responses in Leishmania major-infected BALB/c mice

Mesenchymal stem cell (MSCs) therapy are among new strategies that are used to combat infections through immunomodulation. Cell number, route and frequency of injection and the duration of exposure to the infectious agent are of the main factors to determine the effectiveness of cell therapy. The current study was aimed to assess the effect of multiple intravenous (i.v.) injection of adipose tissue derived (AD)-MSCs on immune response of Leishmania (L.) major-infected BALB/c mice. Therefore, infected mice received AD-MSCs four times during the early phase of infection through i.v. route. They were then monitored weekly for footpad swelling and lesion development. Parasite burden, nitric oxide (NO) and cytokine production were measured in the spleen and lymph node 90 days post-infection. Delayed lesion development, significant reduction in footpad swelling and lower parasite burden in the spleen of AD-MSCs-treated mice showed the relative effect of AD-MSCs therapy in the control of L. major dissemination. In addition, MSCs were able to manage direct cytokine responses toward T‐helper 1 (Th1). Although the level of interleukin (IL)-10 was still higher than the associated level of tumor necrosis factor (TNF)-α, a shift towards higher level of TNF-α was also observed.

Electro-acupuncture at Acupoint ST36 Ameliorates Inflammation and Regulates Th1/Th2 Balance in Delayed-Type Hypersensitivity.

Increasing evidence indicates anti-allergic and anti-inflammatory effects of electro-acupuncture (EA) therapy. However, its underlying mechanism on delayed-type hypersensitivity (DTH), a classic allergic inflammatory disease, still remains unclear. In this study, we aimed to explore the immunomodulatory mechanism of EA intervention in a mouse model of ovalbumin (OVA)-induced DTH. Mice were randomly divided into four groups: Control, OVA-DTH, DTH + EA, DTH + Sham. "Zusanli" acupoint (ST36) was used for DTH + EA, whereas a non-acupoint (localized 5mm below the "Zusanli" acupoint) was selected for DTH + Sham. Footpad thickness was checked, and the infiltration of inflammatory cells was estimated by hematoxylin and eosin staining. Levels of IgG and IgE in serum of different groups and inflammatory cytokines in the supernatants from homogenized footpads, including IFN-γ, TNF-α, IL-4, and IL-5, were determined by ELISA. Cell proliferation of spleen lymphocytes was assayed by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT). The frequency of CD4+IFN-γ+ and CD4+IL-4+ T cells was analyzed with flow cytometry. In addition, the mRNA and protein expression of T-bet and GATA-3 were evaluated by real-time PCR and Western blotting, respectively. Our data showed EA treatment at acupoint ST36 relieved the pathological progression of DTH responses via reduction in footpad swelling, infiltration of inflammatory cells, levels of IgG and IgE as well as decreased production of IFN-γ and TNF-α in homogenized footpad tissue. Moreover, detailed studies were performed revealing that EA attenuated the percentage of CD4+IFN-γ+ T cells and prevented Th cells differentiation into Th1 cells, and this results from inhibiting secretion of IFN-γ and suppressing expression of T-bet, an IFN-γ transcription factor. The results indicated that EA treatment improved Th1-mediated allergic skin inflammation via restoring Th1/Th2 balance by curbing Th1 differentiation. These findings suggested that EA at acupoint ST36 might be a useful and promising therapeutic for allergic inflammatory as well as Th1-mediated inflammation response.

β-Adrenergic blockade protects BALB/c mice against infection with a small inoculum of Leishmania mexicana mexicana (LV4).

In order to test the influence of the sympathetic nervous system on Leishmania mexicana infection, groups of female BALB/c mice were treated (i.p.) with the non-selective β-adrenergic receptor (β-AR) antagonist (S)-propranolol (5mg/kg thrice a day), the β2-AR agonist clenbuterol (1mg/kg once a day) or the α2-AR antagonist yohimbine (2mg/kg twice a day) during 5days. During the second day of treatments, mice were inoculated in the footpad with 1×10(6) or 1×10(3) metacyclic promastigotes of L. mexicana mexicana (LV4). The lesion size was measured weekly, and parasite burden on week 12. In mice treated with (S)-propranolol, the percentage of splenic T lymphocytes producing IFN-γ after antigen challenge was determined by flow cytometry. In mice infected with 1×10(6) parasites, only (S)-propranolol caused a reduction of footpad swelling (p<0.05, weeks 11-12), without effects on parasite burden, or in the percentage of IFN-γ-immunopositive CD4(+) or CD8(+) T lymphocytes. In mice infected with 1×10(3) parasites, the effects of treatments vs. control group were as follows: (a) inhibition of footpad swelling by (S)-propranolol (p<0.01, weeks 3-12), clenbuterol (p<0.05, weeks 7-10), and yohimbine (p<0.01, week 7); (b) a decrease of the parasite burden by (S)-propranolol (p<0.01) and yohimbine (p<0.05); (c) in control mice the percentage of CD4(+) T-cells producing IFN-γ was 6.2±0.5%, while in those treated with (S)-propranolol it increased to 8.7±0.6% (p<0.01); (d) in control mice the percentage of CD8(+) T-cells producing IFN-γ was 3.1±0.4%, while in those treated with (S)-propranolol it increased to 10.4±0.2% (p<0.01). These results indicate that the blockade of β-ARs during infection of BALB/c mice with an inoculum of L. mexicana mexicana similar to that delivered by the bite of a sand fly produces a Th1 bias in the immune response, favoring an increment of T lymphocytes secreting IFN-γ, which correlated with a reduced parasite burden (p<0.05, Spearman's test). We suggest that β-AR antagonists could be of therapeutic value, either as treatment or as adjuvant of vaccines for L. mexicana.

Leishmania donovani recombinant iron superoxide dismutase B1 protein in the presence of TLR-based adjuvants induces partial protection of BALB/c mice against Leishmania major infection

In this study, we tested the protective efficacy of recombinant Leishmania donovani iron superoxide dismutase B1 (SODB1) against Leishmania major infection in BALB/c mice. Mice were challenged with L. major 3weeks after the second boost immunization with rSODB1 alone or in the presence of adjuvants. Injection of BALB/c mice with rSODB1 alone elicited both humoral and cellular immune responses. Administration of rSODB1 with CpG ODN or GLA-SE (a synthetic toll-like receptor 4 agonist) adjuvant resulted in the induction of anti-SODB1 IgG1, and more importantly of significantly high levels of IgG2a isotype. Immunization of mice with rSODB1 alone or with adjuvant induced the production of IFN-γ by splenocytes in response to stimulation with L. major soluble leishmanial antigens (SLA). Moreover, immunization protocols involving rSODB1 resulted in a significant decrease in IL-10 as compared to controls. The presence of CpG ODN or GLA-SE adjuvant in the immunization protocols resulted in a relative increase in IFN-γ in response to stimulation with rSODB1 in comparison to immunization with rSODB1 alone. Mice immunized with rSODB1 plus CpG ODN or GLA-SE, were able to partially control their Leishmania infections, as indicated by the reduction in footpad swelling and parasite numbers, compared to controls. These results suggest that immunization with recombinant SODB1 protein together with CpG ODN or GLA-SE can be potential vaccine candidate against leishmaniasis.

Oral Administration of 1,4-Aryl-2-mercaptoimidazole Inhibits T-Cell Proliferation and Reduces Clinical Severity in the Murine Experimental Autoimmune Encephalomyelitis Model

T cells play a pivotal role in the initiation and progression of multiple sclerosis. We have found that 1,4-aryl-2-mercaptoimidazole (KRM-III) inhibited T-cell antigen receptor- and phorbol myristate acetate/ionomycin-induced activation of nuclear factor of activated T cells (NFAT) and T-cell proliferation with an IC(50) of 5 microM. The KRM-III-mediated inhibitory effect was specific for NFAT activation but not for nuclear factor kappaB. Oral administration of 90 mg/kg KRM-III resulted in complete abrogation of anti-CD3 antibody-induced T-cell activation and a 45.8% reduction in footpad swelling in bovine serum albumin-induced delayed-type hypersensitivity. In the murine experimental autoimmune encephalomyelitis (EAE) model, oral administration of KRM-III significantly attenuated the severity of disease when given before or after disease onset. Draining lymph node cells from KRM-III-treated mice showed markedly reduced proliferation in response to myelin oligodendrocyte glycoprotein peptide. Histological analysis indicated that KRM-III reduced the infiltration of inflammatory cells to the white matter of spinal lumbar cords. These results demonstrate that KRM-III efficiently inhibits T-cell activation and inflammatory responses and lessens EAE clinical signs, which suggest KRM-III as a potential lead compound for the treatment of T-cell-driven autoimmune diseases.

The Nucleoside hydrolase DNA vaccine VR1012NH36 in prophylactic vaccination against mice tegumentar leishmaniasis

The VR1012NH36 DNA vaccine was immunoprophylactic and immunotherapeutic against mice visceral leishmaniasis by L.(L.) chagasi and cutaneous leishmaniasis by L. (L.) mexicana. We here evaluated the protection induced by three sc doses of FML (150μg) + saponin (100μg), or two doses of VR1012 empty plasmid (100μg) or VR1012NH36 (100μg) vaccine against the footpad L. (L.) amazonensis infection with 1 million promastigotes. After infection, the anti-FML IgG, IgG1 and IgG2a antibodies were significantly increased over the saline controls only in the FML saponin vaccinated animals. The DTH response against L.(L.) amazonesis lysate was increased by both vaccines over the saline controls before infection. Regarding the reduction of parasite lesions, at week 26 after infection, significant differences were found in the footpad swelling (ANOVA; p=0.004). Protection was measured as the reduction in footpad swelling. Considering the mean values of each group as well as the individual results, the highest protection was determined by the DNA vaccine followed by the FML saponin vaccine. The DNA vaccine induced 80.4%, the empty plasmid 26.5% and the FML vaccine, 49% of reduction (p<0.05) indicating antigen-specific protection. Indeed, the increase in footpad sizes was detected in 5 of 7 mice treated with saline, 3 treated with empty plasmid, in 1 treated with the FML and in only 2 treated with the NH36 DNA vaccine. Noteworthy, the increase in the NH36 DNA treated mice started on week 26 while in other groups, between weeks 12-14. At the end of the assay, on week 33, survival was 90% for the DNA vaccine group and 70% for the empty plasmid, FMLSAP and saline treated animals. Of note, while deaths begun at week 12 in other groups, the only obit in the DNA vaccinated animals occurred at week 33. Our results point out that the NH36 gene of L. (L.) donovani, as a DNA vaccine, followed by the FMLSAP vaccine, induce significant cross-protective response against tegumentar leishmaniasis induced by L.(L.) amazonensis, indicating its potential use as a bivalent vaccine against visceral and tegumentar leishmaniasis.

Preventative antiinflammatory effect of potamogetonan, a pectin from the common pondweed Potamogeton natans L.

The pectic polysaccharide named potamogetonan (PN) was obtained using extraction of the leaves and stems of the common pondweed Potamogeton natans L. by an aqueous ammonium oxalate. The purified potamogetonan PN-300 was obtained using membrane ultrafiltration of PN and proved to be pectin with a molecular weight of 300 kDa. The capacity of potamogetonan PN-300 to prevent inflammation was assessed using a carrageenan paw edema test in mice. Oral administration of PN-300 24 h prior to induction of inflammation was found to reduce edema formation in a dose-related manner. The maximal effect of PN-300 was observed at 1 h after carrageenan injection (60% reduction of footpad swelling) and was comparable to that of indomethacin. The delayed edema (5 h) was less affected by pre-administration of PN-300 (33% reduction). PN-300 was found to improve the survival of mice subjected to a lethal dose of LPS. The anti-endotoxemic effect of PN-300 was shown to be mediated by decreased TNF-alpha and IL-1beta and increased IL-10 production.Thus, a pectin named potamogetonan PN-300 was isolated from P. natans and was shown to possess a preventive antiinflammatory effect following oral administration.

Effects of tumor necrosis factor alpha on dendritic cell accumulation in lymph nodes draining the immunization site and the impact on the anticryptococcal cell-mediated immune response.

Cell-mediated immune (CMI) responses and tumor necrosis factor alpha (TNF-alpha) have been shown to be essential in acquired protection against Cryptococcus neoformans. Induction of a protective anticryptococcal CMI response includes increases in dendritic cells (DC) and activated CD4(+) T cells in draining lymph nodes (DLN). During the expression phase, activated CD4(+) T cells accumulate at a peripheral site where cryptococcal antigen is injected, resulting in a classical delayed-type hypersensitivity (DTH) reaction. Induction of a nonprotective anticryptococcal CMI response results in no significant increases in the numbers of DC or activated CD4(+) T cells in DLN. This study focuses on examining the role of TNF-alpha in induction of protective and nonprotective anticryptococcal CMI responses. We found that neutralization of TNF-alpha at the time of immunization with the protective immunogen (i) reduces the numbers of Langerhans cells, myeloid and lymphoid DC, and activated CD4(+) T cells in DLN and (ii) diminishes the total numbers of cells, the numbers of activated CD4(+) T cells, and amount of gamma interferon at the DTH reaction site. Although TNF-alpha neutralization during induction of the nonprotective CMI response had little effect on cellular and cytokine parameters measured, it did cause a reduction in footpad swelling when mice received challenge in the footpad. Our findings show that TNF-alpha functions during induction of the protective CMI response by influencing the accumulation of all three DC subsets into DLN. Without antigen stimulated DC in DLN, activated CD4(+) T cells are not induced and thus not available for the expression phase of the CMI response.