Immunization with a Synthetic Peptide Vaccine Fails to Protect Mule Deer (Odocoileus hemionus) from Chronic Wasting Disease

Abstract

ABSTRACT:Chronic wasting disease (CWD) adversely affects both wild and captive cervid populations. A vaccine to prevent CWD would be a highly desirable tool to aid in disease management. To this end, we tested in mule deer a combination of CWD vaccines consisting of cervid prion peptide sequences 168-VDQYNNQNTFVHDC-182 and 145-NDYEDRYYRENMYRYPNQ-164 that had previously been shown to delay onset of clinical disease and increase survival in a mouse-adapted scrapie model. Thirteen captive mule deer (Odocoileus hemionus) were divided into vaccine (n57) and control groups (n56), and given prime and boost vaccinations intramuscularly 5 wk apart. Eight weeks postprime (3 wk postboost), all animals were challenged via natural exposure to an environment contaminated with infective CWD prions. Deer were monitored intermittently for prion infection by rectal and tonsil biopsies beginning 275 days postchallenge. All vaccinates responded to both peptide conjugates present in the combination vaccine as measured by enzyme-linked immunosorbent assay. However, all deer eventually became infected regardless of vaccine status.

Chronic wasting disease in white‐tailed deer: infection, mortality, and implications for heterogeneous transmission

“…Alternatively, vaccination strategies might eventually prove successful, but so far no vaccines have been demonstrated to be effective in preventing CWD infection (Pilon et al. , Goñi et al. ).…”

“…4) represent W A , transmission among all classes with transmission that differs based on the source (yearlings, adult females, and adult males) of infection; W B1 , no transmission among adult males and yearlings, equal transmission among adult females and yearlings, distinct transmission between adult males, and symmetric transmission between adult females and males; W B2 , like W B1 , with asymmetric transmission from females to males as two times that of transmission from males to females; W B3 , like W B2 , with asymmetric transmission from females to males as three times that of transmission from males to females. Transmission coefficients denoted by symbols are identical to the corresponding numerical values in the table. demonstrated to be effective in preventing CWD infection (Pilon et al 2013, Goñi et al 2015. A third alternative for CWD control involves potential disruption of disease transmission to adult males, which could reduce the rate of infection and therefore the male and population prevalence.…”

Cellulose ether treatment in vivo generates chronic wasting disease prions with reduced protease resistance and delayed disease progression

“…Despite considerable efforts to develop an effective vaccine to contain CWD expansion (Pilon et al . ; Goni et al . ; Taschuk et al .…”

“…The geographic range of CWD expanded to 26 US states and 3 Canadian provinces in North America, as well as Norway, Finland, and Sweden in Northern Europe (CDC C. f. D. C. a. P. (2019)). Despite considerable efforts to develop an effective vaccine to contain CWD expansion (Pilon et al 2013;Goni et al 2015;Taschuk et al 2017;Abdelaziz et al 2017;Abdelaziz et al 2018), the eradication of CWD seems not to be realistic to date. In addition, extended incubation periods, subtle early clinical signs, a persisting infectious agent in the environment, and incomplete understanding of transmission all constrain options for controlling CWD.…”

Mucosal immunization with an attenuated Salmonella vaccine partially protects white-tailed deer from chronic wasting disease

“…Recently Pilon et al assessed systemic immunization in deer with PrP peptides, but documented only titers to the synthetic peptides and failed to produce any therapeutic effect [29]. Mucosal immunization is potentially an ideal means to prevent prion transmission and infection which typically has an oral route.…”