Env-expressing autologous T lymphocytes induce neutralizing antibody and afford marked protection against feline immunodeficiency virus.
The envelope (Env) glycoproteins of HIV and other lentiviruses possess neutralization and other protective epitopes, yet all attempts to induce protective immunity using Env as the only immunogen have either failed or afforded minimal levels of protection. In a novel prime-boost approach, specific-pathogen-free cats were primed with a plasmid expressing Env of feline immunodeficiency virus (FIV) and feline granulocyte-macrophage colony-stimulating factor and then boosted with their own T lymphocytes transduced ex vivo to produce the same Env and interleukin 15 (3 x 10(6) to 10 x 10(6) viable cells/cat). After the boost, the vaccinees developed elevated immune responses, including virus-neutralizing antibodies (NA). Challenge with an ex vivo preparation of FIV readily infected all eight control cats (four mock vaccinated and four naïve) and produced a marked decline in the proportion of peripheral CD4 T cells. In contrast, five of seven vaccinees showed little or no traces of infection, and the remaining two had reduced viral loads and underwent no changes in proportions of CD4 T cells. Interestingly, the viral loads of the vaccinees were inversely correlated to the titers of NA. The findings support the concept that Env is a valuable immunogen but needs to be administered in a way that permits the expression of its full protective potential.
Dipartimento di Patologia Sperimentale, Università di Pisa, Via San Zeno 37, I-56127 Pisa, Italy. pistello@biomed.unipi.it
Mauro
M
Pistello
Francesca
F
Bonci
Elisa
E
Zabogli
Francesca
F
Conti
Giulia
G
Freer
Fabrizio
F
Maggi
Mario
M
Stevenson
Mauro
M
Bendinelli
D000276:Adjuvants, Immunologic / Q000008:administration & dosage; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D018791:CD4 Lymphocyte Count; D002415:Cats; D016181:Feline Acquired Immunodeficiency Syndrome / Q000276:immunology / Q000517:prevention & control*; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000008:administration & dosage; D007117:Immunization, Secondary / Q000379:methods; D016089:Immunodeficiency Virus, Feline / Q000276:immunology*; D010957:Plasmids / Q000008:administration & dosage / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014611:Vaccination / Q000379:methods; D019444:Vaccines, DNA / Q000008:administration & dosage / Q000276:immunology; D014759:Viral Envelope Proteins / Q000235:genetics / Q000276:immunology*; D019562:Viral Load
D000276:Adjuvants, Immunologic; D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D019444:Vaccines, DNA; D014759:Viral Envelope Proteins; D016178:Granulocyte-Macrophage Colony-Stimulating Factor