Longitudinal assessment of feline immunodeficiency virus kinetics in plasma by use of a quantitative competitive reverse transcriptase PCR

Abstract

Cats infected with feline immunodeficiency virus (FIV) develop a disease syndrome similar to that caused by human immunodeficiency virus type 1 (HIV-1) infection in humans. HIV-1 replication has been shown to correlate with the disease stage and progression. To assess replication kinetics and disease progression in early FIV infection, we developed a quantitative competitive reverse transcriptase PCR to measure the plasma virus load at serial time points after virus exposure. We found that an early peak viremia immediately preceded the onset of acute-phase symptoms in infected cats. Plasma virus levels remained high throughout the symptomatic phase of infection, which lasted for 8 to 10 weeks, and then declined as clinical symptoms resolved; however, all cats maintained significant plasma virus titers through 36 weeks postinfection. Early peak viral replication coincided with the initial precipitous decline in circulating CD4 ؉ T lymphocytes. These results indicate that FIV kinetics are similar to those of HIV-1 during the acute and secondary phases of infection and that the plasma FIV load correlates with the disease stage. These results serve to further develop the FIV model and to enhance its usefulness for pathogenesis, vaccine development, and therapeutic studies related to HIV.

TaqMan Real-Time Reverse Transcription-PCR and JDVp26 Antigen Capture Enzyme-Linked Immunosorbent Assay To Quantify Jembrana Disease Virus Load during the Acute Phase of In Vivo Infection

“…Rectal temperatures were recorded at the same time daily on days 0, 2, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, and 15. Plasma samples were collected on days Ϫ1, 0, 1,2,4,5,6,7,8,9,10,11,12,14, and 16 postchallenge and were stored at Ϫ80°C prior to testing. Samples were thawed and tested by capture ELISA at the same time that the RNA extractions were carried out to minimize sample degradation.…”

“…In this paper, we describe the development and correlation of two techniques for the detection and quantification of the JDV load in plasma: the quantification of virus RNA and the quantification of virus antigen by enzyme-linked immunosorbent assay (ELISA). The quantification of circulating viral RNA is a widely accepted method for monitoring the levels of human immunodeficiency virus (HIV) RNA, and the quantity of circulating viral RNA is considered a key indicator of lentivirus disease progression and severity (6,12,15,38,45). The tests used to quantify viral RNA require specialized equipment and reagents that may not always be available, and several reports have described the use of antigen capture ELISA techniques for quantification of viruses, including HIV type 1 (HIV-1) (37) and severe acute respiratory syndrome-associated coronavirus (5).…”

Unique Susceptibility of the Fetal Thymus to Feline Immunodeficiency Virus Infection: An Animal Model for HIV Infection In Utero1

“…The first phase, which lasts for about 3 months after initial infection, results in detectable viremia, a high level of circulating CD4 + lymphocyte infection 33,34 and an abrupt decline in CD4 + lymphocytes from the peripheral blood. 35 By the third week, the virus has established productive infection within the thymus, regional lymph nodes, and mucosa-associated lymphoid tissues. 34,36,37 Virus is also detected in body secretions, including saliva 13 , milk/colostrum, 13,14 vaginal secretions, 13 and semen.…”

Animal Models of Retroviral Encephalopathies: Feline Model

“…Prepare a competitor plasmid to serve as an internal reference for quantitation of the FIV provirus. Purify the competitor plasmid from bacterial cultures using standard techniques (see Diehl et al, 1995b;and CPMB UNIT 1.6) and quantify by UV absorbance.…”

“…The 272-bp competitor insert as constructed according to Diehl et al (1995b) has a molecular weight of 168,044 Da. Add the molecular weight of the vector to this value to get the molecular weight of the entire competitor plasmid.…”