Differences in Env and Gag protein expression patterns and epitope availability in feline immunodeficiency virus infected PBMC compared to infected and transfected feline model cell lines.
Env and Gag are key components of the FIV virion that are targeted to the plasma membrane for virion assembly. They are both important stimulators and targets of anti-FIV immunity. To investigate and compare the expression pattern and antigenic changes of Gag and Env in various research models, infected PBMC (the natural FIV host cells) and GFox, and transfected CrFK were stained over time with various Env and Gag specific MAbs. In FIV infected GFox and PBMC, Env showed changes in epitope availability for antibody binding during processing and trafficking, which was not seen in transfected CrFK. Interestingly, epitopes exposed on intracellular Env and Env present on the plasma membrane of CrFK and GFox seem to be hidden on plasma membrane expressed Env of FIV infected PBMC. A kinetic follow up of Gag and Env expression showed a polarization of both Gag and Env expression to specific sites at the plasma membrane of PBMC, but not in other cell lines. In conclusion, mature trimeric cell surface expressed Env might be antigenically distinct from intracellular monomeric Env in PBMC and might possibly be unrecognizable by feline humoral immunity. In addition, Env expression is restricted to a small area on the plasma membrane and co-localizes with a large moiety of Gag, which may represent a preferred FIV budding site, or initiation of virological synapses with direct cell-to-cell virus transmission.
Ghent University, Faculty of Veterinary Medicine, Department of Virology, Parasitology and Immunology, Laboratory of Virology, Merelbeke, Belgium.
Inge D M
IDM
Roukaerts
Custom Monoclonals International, West Sacramento, United States.
Chris K
CK
Grant
Ghent University, Faculty of Veterinary Medicine, Department of Virology, Parasitology and Immunology, Laboratory of Virology, Merelbeke, Belgium.
Sebastiaan
S
Theuns
Ghent University, Faculty of Veterinary Medicine, Department of Virology, Parasitology and Immunology, Laboratory of Virology, Merelbeke, Belgium.
Isaura
I
Christiaens
Ghent University, Faculty of Veterinary Medicine, Department of Virology, Parasitology and Immunology, Laboratory of Virology, Merelbeke, Belgium.
Delphine D
DD
Acar
Ghent University, Faculty of Veterinary Medicine, Department of Virology, Parasitology and Immunology, Laboratory of Virology, Merelbeke, Belgium.
Sebastiaan
S
Van Bockstael
Ghent University, Faculty of Veterinary Medicine, Department of Virology, Parasitology and Immunology, Laboratory of Virology, Merelbeke, Belgium.
Lowiese M B
LMB
Desmarets
Ghent University, Faculty of Veterinary Medicine, Department of Virology, Parasitology and Immunology, Laboratory of Virology, Merelbeke, Belgium. Electronic address: hans.nauwyck@ugent.be.
Hans J
HJ
Nauwynck
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology / Q000378:metabolism; D000914:Antibodies, Viral / Q000276:immunology; D002415:Cats; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D002478:Cells, Cultured; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D016181:Feline Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000821:virology; D015870:Gene Expression; D015686:Gene Products, env / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D015683:Gene Products, gag / Q000737:chemistry / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D006031:Glycosylation; D016089:Immunodeficiency Virus, Feline / Q000502:physiology*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism* / Q000821:virology*; D011485:Protein Binding / Q000276:immunology; D054730:Protein Interaction Domains and Motifs / Q000276:immunology; D055503:Protein Multimerization
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000939:Epitopes; D015686:Gene Products, env; D015683:Gene Products, gag