The feline immunodeficiency virus-infected cat: a model for lentivirus-induced placental immunopathology and reproductive failure (mini-review).
OBJECTIVE
Pediatric human immunodeficiency virus (HIV) infection is largely a result of transplacental transmission, and pregnancy perturbation is more frequent in HIV-infected women. Dysregulation of placental immunology may occur during HIV infection, possibly facilitating HIV vertical transfer and miscarriage. The (FIV)-infected cat is a useful small-animal model for HIV pathogenesis because the viruses share common biological and clinical features. Transplacental transmission is readily achieved experimentally, resulting in a high proportion of infected offspring and frequent reproductive failure.


METHODS
We are using this model to examine lentivirus-induced placental immunopathology to determine the role aberrant immunology plays in intrauterine transmission and pregnancy perturbation.


RESULTS
Kittens were cesarean delivered from FIV-B-2542-infected and control queens at week 8 gestation (1 week short of term), and placental and fetal specimens were collected. On average, control queens delivered 3.8 kittens/litter, and 1 of 31 kittens (3.2%) was non-viable. FIV-infected queens produced 2.7 kittens/litter with 15 of 25 fetuses (60%) non-viable. The virus was detected in 14 of 15 placentas (93%) and 21 of 22 fetuses (95%) using polymerase chain reaction (PCR). Using a one-step, real time reverse transcriptase (RT)-PCR, we measured expression of representative placental T helper 1 (Th1) cytokines, interleukin (IL)-1beta and interferon (IFN)-gamma, a Th2 cytokine, IL-10, and chemokine receptor CXCR4. A comparison of placental cytokine expression between infected and control queens did not reveal differences between the two groups. However, elevated expression of Th1 cytokines and increased Th1/Th2 ratios (IL-1beta/IL-10) occurred in placentas from resorptions, indicating that increased placental Th1 cytokine expression was associated with pregnancy failure in the FIV-infected cat.


CONCLUSIONS
The potential to establish efficient FIV in utero transmission, coupled with the parallels in immunopathology between FIV-infected cats and HIV-infected humans, suggests the usefulness of the FIV-infected cat as a cost-effective, small-animal model to study lentivirus-induced immunopathology, transplacental infection, and reproductive failure.
Coats
Karen S
KS
Department of Biological Sciences and College of Veterinary Medicine, Mississippi State University, PO Box GY, MS 39762, USA. kcoats@biology.msstate.edu
D000818:Animals; D002415:Cats; D004195:Disease Models, Animal; D005260:Female; D005313:Fetal Death / Q000276:immunology* / Q000473:pathology / Q000821:virology; D006801:Humans; D016089:Immunodeficiency Virus, Feline / Q000276:immunology; D016180:Lentivirus Infections / Q000276:immunology* / Q000401:mortality / Q000473:pathology*; D010920:Placenta / Q000276:immunology* / Q000473:pathology* / Q000821:virology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000276:immunology* / Q000401:mortality / Q000473:pathology / Q000821:virology; D011270:Pregnancy, Animal