Erdenebileg Uyangaa

Oral co-administration of live attenuated Salmonella enterica serovar Typhimurium expressing chicken interferon-α and interleukin-18 enhances the alleviation of clinical signs caused by respiratory infection with avian influenza virus H9N2.

The combined use of cytokines has shown synergistic and/or additive effects in controlling several viral infections of livestock animals. However, little is known concerning the practical use of chicken cytokine combinations to control avian diseases. Here, we investigated the antiviral efficacy of oral co-administration of chicken interferon-α (chIFN-α) and chicken interleukin-18 (chIL-18) using attenuated Salmonella enterica serovar Typhimurium in chickens infected with avian influenza virus (AIV) H9N2. Our results demonstrate that oral co-administration of S. enterica serovar Typhimurium expressing chIFN-α and chIL-18 produced a greater alleviation of clinical signs caused by respiratory infection with AIV H9N2 in chickens, when compared to administration of S. enterica serovar Typhimurium expressing either chIFN-α or chIL-18 alone. Mortality, clinical symptom severity, and feed and water intake were used to access treatment effectiveness. This enhancement of antiviral immunity was further confirmed by evidence of reduced rectal shedding and decreased replication of AIV H9N2 in several different tissues of challenged chickens including trachea, lung, cecal tonsil, and brain. Furthermore, oral co-administration of chIFN-α and chIL-18 more efficiently modulated the immune responses of chickens against AIV H9N2 by enhancing both humoral and Th1-biased cell-mediated immunity, compared to single administration of either construct. Therefore, our results suggest that the combined administration of two chicken cytokines, chIFN-α and chIL-18, using attenuated S. enterica serovar Typhimurium as an oral carrier, provides an effective means for controlling respiratory disease caused by AIV H9N2 infection.

Oral administration of Salmonella enterica serovar Typhimurium expressing swine interleukin-18 induces Th1-biased protective immunity against inactivated vaccine of pseudorabies virus.

Enhancing and/or modulating innate and adaptive immunity by cytokines appears to be greatly useful to provide effective protective immunity against infectious diseases. However, an effective delivery system for mass administration in livestock industry is needed because of limitations such as cost, labor, time, and protein stability. Here the immunomodulatory functions of swine interleukine-18 (swIL-18), known as IFN-γ-inducing factor (IGIF), were evaluated in a vaccination model of pseudorabies virus (PrV) using attenuated Salmonella enterica serovar Typhimurium as the oral delivery system. The oral administration of S. enterica serovar Typhimurium expressing swIL-18 prior to vaccination with inactivated PrV vaccine induced enhanced levels of serum PrV-specific IgG and its IgG2 isotype, compared to administration of S. enterica serovar Typhimurium harboring the empty vector. Furthermore, S. enterica serovar Typhimurium expressing swIL-18 mounted Th1-biased cellular immune responses against PrV antigen, as evaluated by the production of IFN-γ and IL-4 from peripheral blood mononuclear cells of piglets. Subsequently, Th1-biased immunity induced by S. enterica serovar Typhimurium expressing swIL-18 showed rapid response and rendered piglets displayed more alleviated clinical signs following the virulent PrV challenge. Also, this alleviation of clinical signs was further confirmed by the reduction of nasal excretion of PrV after challenge. The present study demonstrates the extended use of immunomodulatory functions of swIL-18 orally delivered by attenuated S. enterica serovar Typhimurium.

Protective effects of red ginseng extract against vaginal herpes simplex virus infection

Numerous studies have suggested that Korean red ginseng (KRG) extract has various immune modulatory activities both in vivo and in vitro. In this study, we used a mouse model to examine the effects of orally administered KRG extract on immunity against herpes simplex virus (HSV). Balb/c mice were administered with 100, 200, and 400 mg/kg oral doses of KRG extract for 10 d and then vaginally infected with HSV. We found that KRG extract rendered recipients more resistant against HSV vaginal infection and further systemic infection, including decreased clinical severity, increased survival rate, and accelerated viral clearance. Such results appeared to be mediated by increased vaginal IFN-γ secretion. Moreover, increased mRNA expression of IFN-γ, granzyme B, and Fas-ligand was identified in the iliac lymph node and vaginal tracts of KRG extract treated groups (200 and 400 mg/kg). These results suggest that the activities of local natural killer cells were promoted by KRG extract consumption and that KRG may be an attractive immune stimulator for helping hosts overcome HSV infection.

Enhancement of Th1-biased protective immunity against avian influenza H9N2 virus via oral co-administration of attenuated Salmonella enterica serovar Typhimurium expressing chicken interferon-α and interleukin-18 along with an inactivated vaccine

BackgroundControl of currently circulating re-assorted low-pathogenicity avian influenza (LPAI) H9N2 is a major concern for both animal and human health. Thus, an improved LPAI H9N2 vaccination strategy is needed to induce complete immunity in chickens against LPAI H9N2 virus strains. Cytokines play a crucial role in mounting both the type and extent of an immune response generated following infection with a pathogen or after vaccination. To improve the efficacy of inactivated LPAI H9N2 vaccine, attenuated Salmonella enterica serovar Typhimurium was used for oral co-administration of chicken interferon-α (chIFN-α) and chicken interleukin-18 (chIL-18) as natural immunomodulators.ResultsOral co-administration of S. enterica serovar Typhimurium expressing chIFN-α and chIL-18, prior to vaccination with inactivated AI H9N2 vaccine, modulated the immune response of chickens against the vaccine antigen through enhanced humoral and Th1-biased cell-mediated immunity, compared to chickens that received single administration of S. enterica serovar Typhimurium expressing either chIFN-α or chIL-18. To further test the protective efficacy of this improved vaccination regimen, immunized chickens were intra-tracheally challenged with a high dose of LPAI H9N2 virus. Combined administration of S. enterica serovar Typhimurium expressing chIFN-α and chIL-18 showed markedly enhanced protection compared to single administration of the construct, as determined by mortality, clinical severity, and feed and water intake. This enhancement of protective immunity was further confirmed by reduced rectal shedding and replication of AIV H9N2 in different tissues of challenged chickens.ConclusionsOur results indicate the value of combined administration of chIFN-α and chIL-18 using a Salmonella vaccine strain to generate an effective immunization strategy in chickens against LPAI H9N2.

Oral administration of live attenuated Salmonella enterica serovar Typhimurium expressing chicken interferon-α alleviates clinical signs caused by respiratory infection with avian influenza virus H9N2.

Low pathogenic avian influenza (LPAI) H9N2 has attracted considerable attention due to severe commercial losses in the poultry industry. Furthermore, avian influenza virus (AIV) H9N2-infected chickens can be a reservoir for viral transmission to mammals including pigs and humans, complicating control of viral mutants. Chicken interferon-alpha (chIFN-α) may be useful as an exogenous antiviral agent to control AIV H9N2 infection. However, a superior vehicle for administration of chIFN-α is needed because of challenges of protein stability, production cost, and labor associated with mass administration. Presently, oral administration of single dose of attenuated Salmonella enterica serovar Typhimurium expressing chIFN-α alleviated clinical signs and histopathological changes caused by respiratory infection with AIV H9N2 and reduced the excretion of virus in cloacal swab samples. Similarly, chickens administered S. enterica serovar Typhimurium expressing chIFN-α showed inhibited replication of AIV H9N2 in several different tissues including trachea, lung, cecal tonsil, and brain. Furthermore, immune responses specific for challenged AIV H9N2 were enhanced in chickens administered S. enterica serovar Typhimurium expressing chIFN-α, as determined by hemagglutination inhibition assay of sera, proliferation and IFN-γ and interleukin-4 expression by AIV H9N2 antigen-stimulated peripheral blood mononuclear cells and splenocytes. Therefore, oral administration of S. enterica serovar Typhimurium expressing chIFN-α can successfully control clinical signs caused by respiratory infection with AIV H9N2, which provides valuable insight into the use of attenuated Salmonella vaccine as an oral delivery system of chIFN-α to prevent the replication of AIV H9N2 in respiratory tract.

Enhanced protection against infection with transmissible gastroenteritis virus in piglets by oral co-administration of live attenuated Salmonella enterica serovar Typhimurium expressing swine interferon-α and interleukin-18

The enhanced effect of cytokine combinations has been assessed empirically, based on their immunobiological mechanisms. However, far less is known of the enhanced protection of practical cytokine combinations against viral infection in the livestock industry, due to cost and production issues associated with mass administration. This study demonstrates the enhanced protection of oral co-administration of swine interferon-α (swIFN-α) and interleukin-18 (swIL-18) against infection with transmissible gastroenteritis virus (TGEV) in piglets using attenuated Salmonella enterica serovar Typhimurium as carrier of cytokine proteins. A single oral co-administration of S. enterica serovar Typhimurium expressing swIFN-α and swIL-18 induced enhanced alleviation of the severity of diarrhea caused by TGEV infection, compared to piglets administered S. enterica serovar Typhimurium expressing swIFN-α or swIL-18 alone. This enhancement was further observed by the reduction of TGEV shedding and replication, and the expression of IFN-stimulated gene products in the intestinal tract. The results suggest that the combined administration of the swIFN-α and swIL-18 cytokines using attenuated S. enterica serovar Typhimurium as an oral carrier provides enhanced protection against intestinal tract infection with TGEV.

Systemic and mucosal immunity induced by attenuated Salmonella enterica serovar Typhimurium expressing ORF7 of porcine reproductive and respiratory syndrome virus

Oral administration of attenuated Salmonella vaccine may provide valuable advantages such as low cost, easy preparation, and safety. Attenuated Salmonella vaccines also serve as carriers of foreign antigens and immunomodulatory cytokines. Presently, an attenuated Salmonella enterica serovar Typhimurium strain was used as a carrier for open reading frame 7 (ORF7) protein of porcine reproductive and respiratory syndrome virus (PRRSV), a swine pathogen of significant global economic importance. Initially, an attenuated S. enterica serovar Typhimurium expressing ORF7 gene derived from PRRSV Korean isolate was constructed. Following oral administration of a single dose of the attenuated Salmonella vaccine expressing PRRSV ORF7, humoral and cell-mediated immune responses specific for ORF7 were induced at both systemic and mucosal sites including spleen, mesenteric lymph node, Peyers patch, and laminar propria, as evaluated by determining serum ORF7-specific IgG and mucosal IgA responses, as well as Th1- and Th2-type cytokine production from antigen-stimulated T cells. The induced humoral responses were sustained for at least 12weeks post-immunization. In particular, the immunized mice displayed immune responses to both the foreign ORF7 antigen and Salmonella itself. The results indicate the value of attenuated S. enterica serovar Typhimurium as an oral carrier of PRRSV antigenic proteins to induce effective systemic and mucosal immunity.

Live attenuated Salmonella enterica serovar Typhimurium expressing swine interferon-α has antiviral activity and alleviates clinical signs induced by infection with transmissible gastroenteritis virus in piglets

Enhancing innate and acquired immunity by cytokines such as IFN-alpha appears to be useful as a first line of defense against viral infection. However, the practical use of cytokines in livestock is not evident due to cost and production issues associated with mass administration. In this study, we tested the efficacy of live attenuated Salmonella enterica serovar Typhimurium designed to secrete swine IFN-alpha (swIFN-alpha) protein for preventing the clinical signs caused by infection with transmissible gastroenteritis virus (TGEV), one of the diarrhea-causing viruses in the swine industry. Attenuated Salmonella vaccine (chi8501) containing swIFN-alpha-encoding pYA3560 vector (chi8501/swIFN-alpha) successfully induced the secretion of swIFN-alpha protein into the culture supernatants, as confirmed by SDS-PAGE and Western blot. The culture supernatants of chi8501/swIFN-alpha had antiviral activity against TGEV with 50% effective dose (ED(50)) of 320 per mg of supernatant protein. In addition, oral administration of chi8501/swIFN-alpha reduced the severity of clinical signs caused by TGEV infection with the effect more apparent at 6-8 days post-infection, and reduced excretion of TGEV in feces. Similarly, the amount of TGEV in intestinal tissues and mesenteric lymph node of chi8501/swIFN-alpha-administered piglets was lower than in piglets that were treated with control bacteria. These results indicate the value of attenuated Salmonella vaccines as delivery systems of cytokines that can be used for mass administration, thereby overcoming cost and production issues.

Distinct Upstream Role of Type I IFN Signaling in Hematopoietic Stem Cell-Derived and Epithelial Resident Cells for Concerted Recruitment of Ly-6Chi Monocytes and NK Cells via CCL2-CCL3 Cascade.

Type I interferon (IFN-I)-dependent orchestrated mobilization of innate cells in inflamed tissues is believed to play a critical role in controlling replication and CNS-invasion of herpes simplex virus (HSV). However, the crucial regulators and cell populations that are affected by IFN-I to establish the early environment of innate cells in HSV-infected mucosal tissues are largely unknown. Here, we found that IFN-I signaling promoted the differentiation of CCL2-producing Ly-6Chi monocytes and IFN-γ/granzyme B-producing NK cells, whereas deficiency of IFN-I signaling induced Ly-6Clo monocytes producing CXCL1 and CXCL2. More interestingly, recruitment of Ly-6Chi monocytes preceded that of NK cells with the levels peaked at 24 h post-infection in IFN-I–dependent manner, which was kinetically associated with the CCL2-CCL3 cascade response. Early Ly-6Chi monocyte recruitment was governed by CCL2 produced from hematopoietic stem cell (HSC)-derived leukocytes, whereas NK cell recruitment predominantly depended on CC chemokines produced by resident epithelial cells. Also, IFN-I signaling in HSC-derived leukocytes appeared to suppress Ly-6Ghi neutrophil recruitment to ameliorate immunopathology. Finally, tissue resident CD11bhiF4/80hi macrophages and CD11chiEpCAM+ dendritic cells appeared to produce initial CCL2 for migration-based self-amplification of early infiltrated Ly-6Chi monocytes upon stimulation by IFN-I produced from infected epithelial cells. Ultimately, these results decipher a detailed IFN-I–dependent pathway that establishes orchestrated mobilization of Ly-6Chi monocytes and NK cells through CCL2-CCL3 cascade response of HSC-derived leukocytes and epithelium-resident cells. Therefore, this cascade response of resident–to-hematopoietic–to-resident cells that drives cytokine–to-chemokine–to-cytokine production to recruit orchestrated innate cells is critical for attenuation of HSV replication in inflamed tissues.

Prophylactic and therapeutic modulation of innate and adaptive immunity against mucosal infection of herpes simplex virus.

Herpes simplex virus types 1 and 2 (HSV-1 and HSV-2) are the most common cause of genital ulceration in humans worldwide. Typically, HSV-1 and 2 infections via mucosal route result in a lifelong latent infection after peripheral replication in mucosal tissues, thereby providing potential transmission to neighbor hosts in response to reactivation. To break the transmission cycle, immunoprophylactics and therapeutic strategies must be focused on prevention of infection or reduction of infectivity at mucosal sites. Currently, our understanding of the immune responses against mucosal infection of HSV remains intricate and involves a balance between innate signaling pathways and the adaptive immune responses. Numerous studies have demonstrated that HSV mucosal infection induces type I interferons (IFN) via recognition of Toll-like receptors (TLRs) and activates multiple immune cell populations, including NK cells, conventional dendritic cells (DCs), and plasmacytoid DCs. This innate immune response is required not only for the early control of viral replication at mucosal sites, but also for establishing adaptive immune responses against HSV antigens. Although the contribution of humoral immune response is controversial, CD4+ Th1 T cells producing IFN-γ are believed to play an important role in eradicating virus from the hosts. In addition, the recent experimental successes of immunoprophylactic and therapeutic compounds that enhance resistance and/or reduce viral burden at mucosal sites have accumulated. This review focuses on attempts to modulate innate and adaptive immunity against HSV mucosal infection for the development of prophylactic and therapeutic strategies. Notably, cells involved in innate immune regulations appear to shape adaptive immune responses. Thus, we summarized the current evidence of various immune mediators in response to mucosal HSV infection, focusing on the importance of innate immune responses.