Effects of incidental infections and immune activation on disease progression in experimentally feline immunodeficiency virus-infected cats.
Specific pathogen-free cats were experimentally infected with feline immunodeficiency virus (FIV) and subsequently exposed to common infectious pathogens and immune stimuli over a 3-year period. Cats with preexisting FIV infection showed signs of disease after exposure to Haemobartonella felis, Toxoplasma gondii, feline herpesvirus-1, and feline calicivirus similar to signs in non-FIV-infected cats, although they were more severe. No adverse effects of immunization with inactivated rabies virus vaccine and a synthetic polyproline immunogen were observed in either FIV-infected or non-FIV-infected cats, whereas the application of a diphtheria-tetanus-pertussis vaccine caused transient fever and lymphadenopathy in both groups of animals. Primary immune responses to pathogens or immunogens were usually delayed or diminished in FIV-infected compared with non-FIV-infected cats. Repeated infections and immune activation had no significant effects on the levels of FIV-specific antibodies or on the proportion of peripheral blood mononuclear cells (PBMCs) containing FIV proviral DNA. However, FIV-infected cats that were not exposed to immune stimuli had lower CD4+ T-lymphocyte numbers and lower CD4+/CD8+ T lymphocyte ratios at the end of the 3-year study than FIV-infected cats exposed to cofactors. The latter also had normal levels of interleukin-3 receptor (IL-2R) and major histocompatibility class II (MHC-II) antigen expression on PBMCs, while FIV-infected cats not exposed to cofactors had up-regulated IL-2R and down-regulated MHC-II antigen expression. It was concluded that repeated immune stimulation did not have a deleterious effect on the course of FIV-induced immunodeficiency.
Reubel
G H
GH
Department of Medicine, School of Veterinary Medicine, University of California, Davis.
Dean
G A
GA
George
J W
JW
Barlough
J E
JE
Pedersen
N C
NC
D000711:Anaplasmataceae Infections / Q000150:complications / Q000662:veterinary*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D016516:CD4-CD8 Ratio; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D017250:Caliciviridae Infections / Q000150:complications / Q000662:veterinary; D017927:Calicivirus, Feline; D002415:Cats; D015721:Diphtheria-Tetanus-Pertussis Vaccine / Q000276:immunology; D016181:Feline Acquired Immunodeficiency Syndrome / Q000150:complications* / Q000276:immunology; D005260:Female; D006566:Herpesviridae Infections / Q000150:complications / Q000662:veterinary; D000949:Histocompatibility Antigens Class II / Q000097:blood; D016089:Immunodeficiency Virus, Feline / Q000235:genetics / Q000276:immunology*; D007958:Leukocyte Count / Q000662:veterinary; D007963:Leukocytes, Mononuclear / Q000382:microbiology; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D009504:Neutrophils / Q000276:immunology; D011897:Random Allocation; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013047:Specific Pathogen-Free Organisms; D050378:T-Lymphocytes, Regulatory / Q000276:immunology; D014124:Toxoplasmosis, Animal / Q000150:complications*; D014777:Virus Diseases / Q000150:complications / Q000662:veterinary*
D000914:Antibodies, Viral; D015721:Diphtheria-Tetanus-Pertussis Vaccine; D000949:Histocompatibility Antigens Class II; D015375:Receptors, Interleukin-2