Tropical Medicine and Infectious Disease Article Rabies Virus Antibodies from Oral Vaccination as a Correlate of Protection against Lethal Infection in Wildlife Susan M. Moore 1,* ID , Amy Gilbert 2, Ad Vos 3, Conrad M. Freuling 4 ID , Christine Ellis 2, Jeannette Kliemt 4 and Thomas Müller 4 ID 1 Kansas State University, Veterinary Diagnostic Laboratory, Rabies Laboratory, Manhattan, KS 66502, USA 2 National Wildlife Research Center, US Department of Agriculture, Animal and Plant Health Inspection Service, Wildlife Services, Fort Collins, CO 80521, USA;
[email protected] (A.G.);
[email protected] (C.E.) 3 IDT Biologika GmbH, 06861 Dessau-Rosslau, Germany;
[email protected] 4 Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Institute of Molecular Virology and Cell Biology, 17493 Greifswald-Insel Riems, Germany; Conrad.Freuling@fli.de (C.M.F.); Jeannette.Kliemt@fli.de (J.K.); Thomas.Mueller@fli.de (T.M.) * Correspondence:
[email protected]; Tel.: +1-785-532-4472 Received: 2 June 2017; Accepted: 8 July 2017; Published: 21 July 2017 Abstract: Both cell-mediated and humoral immune effectors are important in combating rabies infection, although the humoral response receives greater attention regarding rabies prevention. The principle of preventive vaccination has been adopted for strategies of oral rabies vaccination (ORV) of wildlife reservoir populations for decades to control circulation of rabies virus in free-ranging hosts. There remains much debate about the levels of rabies antibodies (and the assays to measure them) that confer resistance to rabies virus. In this paper, data from published literature and our own unpublished animal studies on the induction of rabies binding and neutralizing antibodies following oral immunization of animals with live attenuated or recombinant rabies vaccines, are examined as correlates of protection against lethal rabies infection in captive challenge settings.