Improved health and survival of FIV-infected cats is associated with the presence of autoantibodies to the primary receptor, CD134.
We analyzed antibody responses in sera from feline immunodeficiency virus (FIV)-infected and uninfected cats. A strong antiviral response to the viral surface glycoprotein (SU) was noted in both natural and experimental infections. In addition, 143 of 226 FIV-infected animals (63%) also expressed antibodies to the primary binding receptor, CD134, whereas cats infected with other feline RNA viruses, including calicivirus, coronavirus, herpesvirus, and feline leukemia virus, did not. Both affinity-purified anti-CD134 and anti-SU antibodies blocked FIV infection ex vivo. FACS analyses revealed that the anti-CD134 antibodies bound to a cryptic epitope on the receptor that was only exposed when SU bound to CD134. Anti-CD134 binding caused displacement of SU from the surface of the cell and inhibition of infection. The presence of antibodies to CD134 correlated with lower virus loads and a better overall health status in FIV(+) cats, whereas anti-SU antibodies were present independent of health status. The findings are consistent with a role for antireceptor antibodies in protection from virus spread and disease progression.
Grant
Chris K
CK
Custom Monoclonals International, West Sacramento, CA 95691, USA.
Fink
Elizabeth A
EA
Sundstrom
Magnus
M
Torbett
Bruce E
BE
Elder
John H
JH
D000818:Animals; D001323:Autoantibodies / Q000276:immunology*; D002415:Cats; D002460:Cell Line; D016181:Feline Acquired Immunodeficiency Syndrome / Q000097:blood / Q000276:immunology / Q000503:physiopathology; D006801:Humans; D016089:Immunodeficiency Virus, Feline / Q000276:immunology* / Q000502:physiology; D053262:Receptors, OX40 / Q000276:immunology*; D015996:Survival Rate; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology; D019562:Viral Load; D053586:Virus Internalization
D001323:Autoantibodies; D053262:Receptors, OX40