Monoclonal antibodies to the spike protein of feline infectious peritonitis virus mediate antibody-dependent enhancement of infection of feline macrophages

C W Olsen, W V Corapi, C K Ngichabe, J D Baines, F W Scott
1992 Journal of Virology  
t Present address: Marjorie Kovler Oncology Laboratories, University of Chicago, Chicago, IL 60637. new consideration was introduced in 1989 when Stoddart provided evidence for antibody-dependent enhancement (ADE) of FIPV infection of primary feline peritoneal macrophages in vitro (41). ADE of virus infection occurs when monocytes and macrophages are more efficiently infected by complexes of virus plus antibody (Ab), via Fc receptor-mediated endocytosis, than by virus alone (33). A number of
more » ... 33). A number of human and animal viruses have been shown to be capable of utilizing this mechanism of infection. These include dengue virus and related flaviviruses (8, 32), respiratory syncytial virus (5, 17), influenza virus type A (26, 27), rabies virus (16) , and most recently human immunodeficiency virus type 1 (11, 44), as well as FIPV (41). The FIPV system provides a unique opportunity to investigate ADE of virus infectivity at both the in vitro and in vivo levels. Specific aspects of ADE of FIPV infection need to be elucidated because the immunopathogenesis of FIP has precluded the development of an effective, proven vaccine against FIPV infection (28). The aims of this work were to confirm that virus-specific feline antiserum can mediate ADE of FIPV infectivity in vitro and to determine whether FIPV-specific murine monoclonal Abs (MAbs) can demonstrate similar in vitro enhancement. A panel of MAbs was evaluated to define which viral protein(s) induces enhancing Abs and to determine whether distinct enhancing epitopes may be involved. MATERIALS AND METHODS Cells and viruses. FIPV strains 79-1146 and UCD1 were grown in A72 cells. Virus titers were calculated as 50% 956 on May 9, 2020 by guest
doi:10.1128/jvi.66.2.956-965.1992 fatcat:bq4grgnyqzdtrfwthvxydqfmki