Early pathogenesis of transmucosal feline immunodeficiency virus infection.
To identify the early target cells and tissues in transmucosal feline immunodeficiency virus (FIV) infection, cats were exposed to a clade C FIV isolate via the oral-nasal or vaginal mucosa and multiple tissues were examined by virus isolation coculture (VI), DNA PCR, catalyzed tyramide signal-amplified in situ hybridization (TSA-ISH), and immunohistochemistry between days 1 and 12 postinoculation (p.i.). FIV RNA was detected in tonsil and oral or vaginal mucosa as early as 1 day p.i. by TSA-ISH and in retropharyngeal, tracheobronchial, or external iliac lymph nodes and sometimes in spleen or blood mononuclear cells by day 2, indicating that regional and distant spread of virus-infected cells occurred rapidly after mucosal exposure. By day 8, viral RNA, DNA, and culturable virus were uniformly detected in regional and distant tissues, connoting systemic infection. TSA-ISH proved more sensitive than DNA PCR in detecting early FIV-infected cells. In mucosal tissues, the earliest demonstrable FIV-bearing cells were either within or subjacent to the mucosal epithelium or were in germinal centers of regional lymph nodes. The FIV(+) cells were of either of two morphological types, large stellate or small round. Those FIV RNA(+) cells which could be colabeled for a phenotype marker, were labeled for either dendritic-cell-associated protein p55 or T-lymphocyte receptor antigen CD3. These studies indicate that FIV crosses mucous membranes within hours after exposure and rapidly traffics via dendritic and T cells to systemic lymphoid tissues, a pathway similar to that thought to occur in the initial phase of infection by the human and simian immunodeficiency viruses.
Obert
Leslie A
LA
Department of Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523, USA.
Hoover
Edward A
EA
D000818:Animals; D002371:Cat Diseases / Q000503:physiopathology / Q000635:transmission / Q000821:virology; D002415:Cats; D004279:DNA, Viral / Q000032:analysis; D016181:Feline Acquired Immunodeficiency Syndrome / Q000503:physiopathology / Q000635:transmission / Q000821:virology*; D005260:Female; D016089:Immunodeficiency Virus, Feline / Q000302:isolation & purification / Q000472:pathogenicity* / Q000502:physiology; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods; D016180:Lentivirus Infections / Q000503:physiopathology / Q000635:transmission / Q000662:veterinary* / Q000821:virology; D008221:Lymphoid Tissue / Q000821:virology; D009092:Mucous Membrane / Q000821:virology*; D016133:Polymerase Chain Reaction
D004279:DNA, Viral