Monoclonal antibodies to Cache Valley virus for serological diagnosis

Abstract

Cache Valley virus (CVV) is a mosquito-borne virus in the genus Orthobunyavirus, family Peribunyaviridae. It was first isolated from a Culiseta inorata mosquito in Cache Valley, Utah in 1956 and is known to circulate widely in the Americas. While only a handful of human cases have been reported since its discovery, it is the causative agent of fetal death and severe malformations in livestock. CVV has recently emerged as a potential viral pathogen causing severe disease in humans. Currently, the only serological assay available for diagnostic testing is plaque reduction neutralization test which takes several days to perform and requires biocontainment. To expand diagnostic capacity to detect CVV infections by immunoassays, 12 hybridoma clones secreting anti-CVV murine monoclonal antibodies (MAbs) were developed. All MAbs developed were found to be non-neutralizing and specific to the nucleoprotein of CVV. Cross-reactivity experiments with related orthobunyaviruses revealed several of the MAbs reacted with Tensaw, Fort Sherman, Tlacotalpan, Maguari, Playas, and Potosi viruses. Our data shows that MAbs CVV14, CVV15, CVV17, and CVV18 have high specific reactivity as a detector in an IgM antibody capture test with human sera.

The Adaptive Immune Response against Bunyavirales

“…A distinctive characteristic of orthobunyaviruses is the genetic relatedness of viruses within serogroups, leading to cross-reactive Abs across the genus, including CSG and SSG members [ 145 , 146 , 147 ]. However, whether cross-reactive Abs can protect against multiple infections remains uncertain.…”

“…High N-specific Ab titers are also frequently reported during infection with orthobunyaviruses. However, antibodies against N exhibit sub-neutralizing or non-neutralizing activity, as observed in mice and rabbits infected with LACV, TAHV, SBV, and the Cache valley virus (CCV) [ 147 , 153 , 154 , 155 , 162 ].…”

Cache Valley virus: an emerging arbovirus of public and veterinary health importance

“…Outbred ICR mice were resistant to CVV infection and viral-induced teratogenicity in pregnant mice (Edwards et al 1998). However, interferon receptor-deficient mice are susceptible to CVV infection via peripheral routes of inoculation and vertical transmission of the virus resulting in spontaneous abortions and congenital malformations (Lopez et al 2021, Skinner et al 2022). The lack of an effective interferon response in these mice leading to productive CVV infections is not surprising given that interferon has been shown to play an essential role in restricting growth of orthobunyavirids, including CVV and La Crosse virus (Hefti et al 1999, Kochs et al 2002, Rodrigues Hoffmann et al 2013).…”

“…Anti-viral IgM is produced early in the course of infection, making it an ideal diagnostic analyte for detection of an acute and recent convalescent CVV infection in humans and livestock. The recent development of murine anti-CVV monoclonal antibodies (MAbs) has led to the development of an IgM antibody capture enzyme-linked immunosorbent assay (MAC-ELISA) that is currently undergoing validation at the US Centers for Disease Control's Arboviral Diseases Branch (ADB) diagnostic laboratory (Skinner et al 2022). ADB's diagnostic laboratory uses the MAC-ELISA platform to detect IgM to several medically important arboviruses, including dengue viruses, West Nile virus, St. Louis encephalitis virus, La Crosse virus, Zika virus, and Eastern equine encephalitis virus from acute or convalescent human specimens (Martin et al 2000, 2002).…”

“…One of the limiting factors in performing the CVV MAC-ELISA is the need for human positive control to include in the test because of a lack of human CVV infections. To overcome this, the development of a recombinant murine-human IgM antibody expressed in a stable HEK293 cell line using MAb CVV17 previously described has been undertaken (Skinner et al 2022). This recombinant antibody expressing the variable regions of the murine MAb CVV17 and the human constant regions of IgM can replace human positive control sera making the distribution and implementation of this assay more accessible (unpublished data).…”