The use of green fluorescent protein-tagged virus-like particles as a tracer in the early phase of chikungunya infection.

To visually examine the early phase of chikungunya virus (CHIKV) infection in target cells, we constructed a virus-like particle (VLP) in which the envelope protein E1 is fused with green fluorescent protein (GFP). This chikungunya VLP-GFP (CHIK-VLP-EGFP), purified by density gradient fractionation, was observed as 60-70 nm-dia. particles and was detected as tiny puncta of fluorescence in the cells.

Lymphoid tissue-resident Alcaligenes LPS induces IgA production without excessive inflammatory responses via weak TLR4 agonist activity.

Alcaligenes are opportunistic commensal bacteria that reside in gut-associated lymphoid tissues such as Peyer's patches (PPs); however, how they create and maintain their homeostatic environment, without inducing an excessive inflammatory response remained unclear. We show here that Alcaligenes-derived lipopolysaccharide (Alcaligenes LPS) acts as a weak agonist of toll-like receptor 4 and promotes IL-6 production from dendritic cells, which consequently enhances IgA production. The inflammatory activity of Alcaligenes LPS was weaker than that of Escherichia coli-derived LPS and therefore no excessive inflammation was induced by Alcaligenes LPS in vitro or in vivo.

Genome-Wide Screening Uncovers the Significance of N-Sulfation of Heparan Sulfate as a Host Cell Factor for Chikungunya Virus Infection.

The molecular mechanisms underlying chikungunya virus (CHIKV) infection are poorly characterized. In this study, we analyzed the host factors involved in CHIKV infection using genome-wide screening. Human haploid HAP1 cells, into which an exon-trapping vector was introduced, were challenged with a vesicular stomatitis virus pseudotype bearing the CHIKV E3 to E1 envelope proteins.

Intranasal hydroxypropyl-β-cyclodextrin-adjuvanted influenza vaccine protects against sub-heterologous virus infection.

Intranasal vaccination with inactivated influenza viral antigens is an attractive and valid alternative to currently available influenza (flu) vaccines; many of which seem to need efficient and safe adjuvant, however. In this study, we examined whether hydroxypropyl-β-cyclodextrin (HP-β-CD), a widely used pharmaceutical excipient to improve solubility and drug delivery, can act as a mucosal adjuvant for intranasal flu vaccines. We found that intranasal immunization of mice with hemagglutinin split- as well as inactivated whole-virion influenza vaccine with HP-β-CD resulted in secretion of antigen-specific IgA and IgGs in the airway mucosa and the serum as well.

Neutralization activity of patient sera collected during the 2008-2009 Chikungunya outbreak in Thailand.

Chikungunya virus (CHIKV) infection typically causes fever, rash, myalgia, and arthralgia and sometimes results in recurrent joint pain or, in severe cases, neurological disorders or death. How CHIKV infection leads to prolonged or severe symptoms is still not well understood. In this study, we examined the neutralization (NT) titer of 98 serum samples collected from patients during the 2008-2009 chikungunya outbreak in Thailand.

Evolution of adaptive immunity: implications of a third lymphocyte lineage in lampreys.

An alternative antigen receptor, named the variable lymphocyte receptor (VLR), was first identified in lampreys in 2004. Since then, the mechanism of VLR diversification via somatic gene assembly and the function of VLR-expressing lymphocytes have been the subject of much research. VLRs comprise leucine-rich repeat (LRR) motifs and are found only in the most phylogenetically distant vertebrates from mammals, lampreys, and hagfish.

Development of a pseudotyped-lentiviral-vector-based neutralization assay for chikungunya virus infection.

Chikungunya virus (CHIKV) is a mosquito-borne alphavirus that causes chikungunya fever in Africa, South Asia, and Southeast Asia. Because the mosquito vector Aedes albopictus is present in habitats across Europe, North America, and East Asia, CHIKV has become a serious worldwide public health concern. Infection with CHIKV typically causes fever, rash, myalgia, and arthralgia.

Regulation of antigen-receptor gene assembly in hagfish.

Variable lymphocyte receptors (VLRs) are antigen receptors in the jawless vertebrates lamprey and hagfish. VLR genes are classified into VLRA and VLRB, and lymphocytes expressing VLRA are T-cell-like, whereas those expressing VLRB are B-cell-like in the sea lamprey. Diverse VLR genes are assembled somatically in lymphocytes; however, how the assembly is regulated is still largely unknown.

Antigen-receptor genes of the agnathan lamprey are assembled by a process involving copy choice.

Jawless vertebrates have acquired immunity but do not have immunoglobulin-type antigen receptors. Variable lymphocyte receptors (VLRs) have been identified in lamprey that consist of multiple leucine-rich repeat (LRR) modules. An active VLR gene is generated by the assembly of a series of variable gene segments, including many that encode LRRs.