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In response to the aggressive global spread of the mosquito-borne chikungunya virus (CHIKV), an accurate and accessible diagnostic tool is of high importance. CHIKV, an arthritogenic alphavirus, comprises three genotypes: East/Central/South African (ECSA), West African (WA), and Asian. A previous rapid immunochromatographic (IC) test detecting CHIKV E1 protein showed promising performance for detection of the ECSA genotype. Unfortunately, this kit exhibited lower capacity for detection of the Asian genotype, currently in circulation in the Americas, reflecting the low avidity of one of the monoclonal antibodies (mAbs) in this IC kit for the E1 protein of the Asian-genotype because of a variant amino acid sequence. To address this shortcoming, we set out to generate a new panel of broad-spectrum mouse anti-CHIKV mAbs using hybridoma technology. We report here the successful generation of mouse anti-CHIKV mAbs targeting CHIKV E1 and capsid proteins. These mAbs possessed broad reactivity to all three CHIKV genotypes, while most of the mAbs lacked cross-reactivity towards Sindbis, dengue, and Zika viruses. Two of the mAbs also lacked cross-reactivity towards other alphaviruses, including O'nyong-nyong, Ross River, Mayaro, Western Equine Encephalitis, Eastern Equine Encephalitis, and Venezuelan Equine Encephalitis viruses. In addition, another two mAbs cross-reacted weakly only with most closely related O'nyong-nyong virus. Effective diagnosis is one of the keys to disease control but to date, no antibody-based rapid IC platform for CHIKV is commercially available. Thus, the application of the mAbs characterized here in the rapid diagnostic IC kit for CHIKV detection is expected to be of great value for clinical diagnosis and surveillance purposes. [ABSTRACT FROM AUTHOR]

Vesicular stomatitis virus (VSV) is highly immunogenic and able to stimulate both innate and adaptive immune responses. However, its ability to induce adverse effects has held back the use of VSV as a potential vaccine vector. In this study we developed VSV-ΔP, a safe yet potent replication-defective recombinant VSV in which the phosphoprotein (P) gene was deleted. VSV-ΔP replicated only in supporting cells expressing P (BHK-P cells) and at levels more than 2 logs lower than VSV. In vivo studies indicated that the moderate replication of VSV-ΔP in vitro was associated with the attenuation of this virus in the mouse model, whereas mice intracranially injected with VSV succumbed to neurotoxicity. Furthermore, we constructed VSV and VSV-ΔP expressing a variety of antigens including hemagglutinin-neuraminidase (HN) from Newcastle disease virus (NDV), hemagglutinin (HA) from either a 2009 H1N1 pandemic influenza virus (pdm/09) or the avian H7N9. VSV and VSV-ΔP incorporated the foreign antigens on their surface resulting in induction of robust neutralizing antibody, serum IgG, and hemagglutination inhibition (HAI) titers against their corresponding viruses. These results indicated that VSV with P gene deletion was attenuated in vitro and in vivo, and possibly expressed the foreign antigen on its surface. Therefore, the P gene-deletion strategy may offer a potentially useful and safer approach for attenuating negative-sense RNA viruses which use phosphoprotein as a cofactor for viral replication. [ABSTRACT FROM AUTHOR]

Four serotypes of dengue virus (DENV), type 1 to 4 (DENV-1 to DENV-4), exhibit approximately 25–40% of the difference in the encoded amino acid residues of viral proteins. Reverse transcription of RNA extracted from specimens followed by PCR amplification is the current standard method of DENV serotype determination. However, since this method is time-consuming, rapid detection systems are desirable. We established several mouse monoclonal antibodies directed against DENV non-structural protein 1 and integrated them into rapid DENV detection systems. We successfully developed serotype-specific immunochromatography systems for all four DENV serotypes. Each system can detect 104 copies/mL in 15 min using laboratory and clinical isolates of DENV. No cross-reaction between DENV serotypes was observed in these DENV isolates. We also confirmed that there was no cross-reaction with chikungunya, Japanese encephalitis, Sindbis, and Zika viruses. Evaluation of these systems using serum from DENV-infected individuals indicated a serotype specificity of almost 100%. These assay systems could accelerate both DENV infection diagnosis and epidemiologic studies in DENV-endemic areas. [ABSTRACT FROM AUTHOR]