Comprehensive Mapping of Common Immunodominant Epitopes in the Eastern Equine Encephalitis Virus E2 Protein Recognized by Avian Antibody Responses

Abstract

Eastern equine encephalitis virus (EEEV) is a mosquito-borne virus that can cause both human and equine encephalitis with high case fatality rates. EEEV can also be widespread among birds, including pheasants, ostriches, emu, turkeys, whooping cranes and chickens. The E2 protein of EEEV and other Alphaviruses is an important immunogenic protein that elicits antibodies of diagnostic value. While many therapeutic and diagnostic applications of E2 protein-specific antibodies have been reported, the specific epitopes on E2 protein recognized by the antibody responses of different susceptible hosts, including avian species, remain poorly defined. In the present study, the avian E2-reactive polyclonal antibody (PAb) response was mapped to linear peptide epitopes using PAbs elicited in chickens and ducks following immunization with recombinant EEEV E2 protein and a series of 42 partially overlapping peptides covering the entire EEEV E2 protein. We identified 12 and 13 peptides recognized by the chicken and duck PAb response, respectively. Six of these linear peptides were commonly recognized by PAbs elicited in both avian species. Among them five epitopes recognized by both avian, the epitopes located at amino acids 211–226 and 331–352 were conserved among the EEEV antigenic complex, but not other associated alphaviruses, whereas the epitopes at amino acids 11–26, 30–45 and 151–166 were specific to EEEV subtype I. The five common peptide epitopes were not recognized by avian PAbs against Avian Influenza Virus (AIV) and Duck Plague Virus (DPV). The identification and characterization of EEEV E2 antibody epitopes may be aid the development of diagnostic tools and facilitate the design of epitope-based vaccines for EEEV. These results also offer information with which to study the structure of EEEV E2 protein.

Mapping eastern equine encephalitis virus risk for white-tailed deer in Michigan

“…EEEV infections have been reported in domestic pigs (Elvinger et al, 1996), cattle (McGee et al, 1992), sheep (Bauer et al 2005), dogs (Farrar et al, 2005), and chickens (Griffiths & McClain, 1985), although these species typically do not show signs of disease and instead develop detectable antibodies against the virus. Similar resistance to EEEV has been observed in a variety of wildlife, including some passerine birds (Sun et al, 2013), wading birds (Gottdenker, Howerth, & Mead, 2003), ungulates (Berl et al, 2013; Lubelczyk et al, 2014; Schmitt et al, 2007), and snakes (Bingham et al, 2012). …”

The Structural Biology of Eastern Equine Encephalitis Virus, an Emerging Viral Threat

“…The structural and functional basis of neutralization by monoclonal antibodies (mAbs) has been previously investigated for several alphaviruses such as arthritogenic CHIKV, RRV and MAYV, and encephalitic VEEV and WEEV [ 44 , 45 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 ]. In the context of EEEV, prior investigations have focused on characterization of immune response to E2 peptides and compared their cross-reactivity to VEEV [ 151 , 152 , 153 , 154 ]. Two recent cryoEM investigations have provided structural insights into the neutralization of EEEV by Fab fragments from neutralizing mAbs [ 33 , 39 ].…”

The Structural Biology of Eastern Equine Encephalitis Virus, an Emerging Viral Threat

“…Structural basis of EEEV neutralization by monoclonal antibodies: The structural and functional basis of neutralization by monoclonal antibodies (mAbs) has been previously investigated for alphaviruses such as arthritogenic CHIKV, RRV, and, MAYV, and encephalitic VEEV and WEEV [44,45,[132][133][134][135][136][137][138][139][140][141][142][143][144][145][146][147][148][149][150]. In the context of EEEV, prior investigations have focused on characterization of immune response to E2 peptides and compared their cross-reactivity to VEEV [151][152][153][154]. Two recent cryoEM investigations have provided structural insights into the neutralization of EEEV by Fab fragments from neutralizing mAbs [33,39].…”