ABSTRACT
BACKGROUND: Previously, we have reported that IL-33 functioned as a protective modulator in dextran sulfate sodium- (DSS-) induced chronic colitis by suppressing Th17 cell response in colon lamina propria and IL-33 induced both regulatory B cells (Bregs) and regulatory T cells (Tregs) in mesenteric lymph nodes (MLNs) of mice with DSS-induced acute colitis. Moreover, we speculated that IL-33 would promote the Treg or Breg responses leading to the attenuation of DSS-induced chronic colitis. So, we investigated the role of IL-33 on Bregs and Tregs in the MLN of DSS-induced chronic colitis mice. METHODS: IL-33 was administered by intraperitoneal injection to mice with DSS-induced chronic colitis. Clinical symptoms, colon length, and histological changes were determined. The production of cytokines was measured by ELISA. The T and B cell subsets were measured by flow cytometry. The expression of mRNA of transcription factors was measured by quantitative real-time PCR. RESULTS: We show that IL-33 treatment increases both Breg and Treg responses in the MLN of mice with DSS-induced chronic colitis. Moreover, IL-33 treatment also decreases Th17 cell response in the MLN of mice with DSS-induced chronic colitis. CONCLUSION: Our data provide clear evidence that IL-33 plays a protective role in DSS-induced chronic colitis, which is closely related to increasing Breg and Treg responses in the MLN of mice as well as suppressing Th17 cell responses.
Subject(s)
B-Lymphocytes, Regulatory/immunology , Colitis/immunology , Interleukin-33/immunology , T-Lymphocytes, Regulatory/immunology , Th17 Cells/immunology , Animals , Chronic Disease , Dextran Sulfate , Disease Models, Animal , Humans , Immune Tolerance , Lymphocyte Activation , Male , Mice , Mice, Inbred C57BLABSTRACT
Non-structural protein 1 (NS1) is an important virulence factor encoded by influenza A virus. NS1 can interact with a variety of host cell proteins to interfere with the host innate immune response and to promote effective viral replication. Our previous work has shown that only the effector domain of NS1 (amino acid residues 74-230/237) is sufficient to interact with nucleolar and coiled-body phosphoprotein 1 (NOLC1). To investigate the exact region of NS1 that interacts with NOLC1, we used only the effector domain of NS1 and constructed various mutants having different deletions, and then tested their ability to interact with NOLC1 via pull-down assay. Only the mutant containing amino acid residues 104-200 showed positive interaction with NOLC1. To further determine the key amino acids of the NS1 effector domain which are crucial for interaction with NOLC1, several mutants containing a single amino acid substitution were made and their interaction with NOLC1 was tested. Only the mutant D120A or R195A showed reduced binding with NOLC1, suggesting that D120 and R195 were crucial to the binding of NS1 to NOLC1. This study lays the foundation for further research aiming at furthering our understanding of the interaction between NS1 and host cells.
Subject(s)
Influenza A Virus, H5N1 Subtype/metabolism , Influenza, Human/metabolism , Nuclear Proteins/metabolism , Phosphoproteins/metabolism , Viral Nonstructural Proteins/chemistry , Viral Nonstructural Proteins/metabolism , Amino Acid Sequence , Animals , COS Cells , Chlorocebus aethiops , Humans , Influenza A Virus, H5N1 Subtype/chemistry , Influenza A Virus, H5N1 Subtype/genetics , Influenza, Human/genetics , Influenza, Human/virology , Molecular Sequence Data , Nuclear Proteins/genetics , Phosphoproteins/genetics , Protein Binding , Protein Structure, Tertiary , Sequence Alignment , Viral Nonstructural Proteins/genetics , VirulenceABSTRACT
Genetically modified baculoviruses offer a promising alternative to chemical insecticides in the control of agricultural and forest insect pests. A novel bacmid, HaBacYH6, was constructed in which the ecdysteroid UDP-glucosyltransferase gene (egt) was replaced with a bacterial replication cassette containing a mini-F replicon, a kanamycin resistance gene, and the attTn7 site. Insertion of the enhanced green fluorescence protein gene (egfp) into HaBacYH6 showed that the bacmid can express an active exogenous protein. Bioassays showed that median lethal time (LT50) of HaBacYH6 was 89.23 h in third instar Helicoverpa armigera larvae, 15.81 h earlier than that of wild-type HearNPV-G4, though there was no significant difference in median lethal dose (LD50). The data indicate that HaBacYH6 can be used as a new Bac-to-Bac system, and can also provide a technology platform for generating more effective biological insecticides.