HIV Selectest enzyme immunoassay and rapid test: ability to detect sero-conversion following HIV-1 infection

Most of the currently tested HIV vaccines contain multiple viral components. Due to this many vaccine recipients give positive results when tested for HIV sero-detection. Thus, to differentiate between vaccines induced antibodies and sero-conversion due to true HIV infection, the group of Dr. Hana Golding at Division of viral products, Center for Biologics Evaluation and Research (CBER), FDA, Bathesda, US, developed a new HIV immunoassay termed HIV Selectest. To develop this test, they identified conserved sequences in Env gp41 and Gag p6. These sequences are recognized soon after the infection but are not included in most HIV vaccine candidates. In that study, the investigators observed that HIV-Selectest could become an important differential diagnostic tool for HIV vaccine trials, blood banks and population screening worldwide.

In the present study, the investigators of Dr. Golding's lab together with investigators from various research institutes in Africa and USA, developed a rapid version of the HIV selectest in order to facilitate point of care testing during vaccine trials.

The authors obtained serial samples from following multiple cohorts of men and women from the United States and Africa:

• Plasma donors who acquired HIV-1 in the US (Center for HIV/AIDS Vaccine Immunology, CHAVI, clade B, predominantly males)
  
• High risk subjects identified with having acute HIV-1 infections in US sites participating in the Acute Infection and Early Disease Research Program (AIEDRP, clade B, predominantly males)
  
• Acutely infected subjects identified in Africa by the center for AIDS program of Research in South Africa (CAPRISA, clade C, mostly women)
  
• Subjects participating in the Zambia-Emory HIV research project (ZEHRP, clade C)
  
• Early post-infection time points in men enrolled in the US multicenter AIDS cohort study (MACS) and
  
• Women participating in the women's interagency HIV study (WIHS)
  

Results:

Of the 87 sero-conversion plasma donors tested, only 45 reached sero-conversion when HIV-selectest was performed on them. Of these 45 panels, concordant results with Abbott third generation tests and HIV-Selectest test were seen in 18 panels. The Abbott test detected positive results prior to Selectest in 20 of the 45 panels. The Selectest detected positive prior to Abbott test in 7 of 45 panels. On an average, the Selectest detected anti-HIV antibodies 1.6 days after the commercial Abbott test. In the other panels (AIEDRP, MACS, WIHS) the sensitivity of HIV Selectest ranged from 98.7 to 100% and from 93.8 to 98.3% in men and women, respectively. In case of clade C infections (CAPRISA), the HIV-Selectest was positive in later than one sample after sero-conversion. Taken together all these data indicated that the sensitivity of HIV-Selectest EIA was comparable to commercially available tests which are used in the HIV screening algorithm in many countries. To further evaluate and compare the sensitivity of HIV-Selectest rapid test and EIA with the commercially available third generation test, authors examined sero-conversion panels from Sera care Bioservices, Inc. In the case of panel PRB917, the Abbott HIV-1/2-O test was reactive on day 28, while the HIV-selectest EIA and rapid tests were positive on day 14.

Source: Khurana S, Norris PJ, Busch MP, Haynes BF, Park S, Sasono P,

 Mlisana K, Salim AK, Hecht FM, Mulenga J, Chomba E, Hunter E, Allen

 S, Nemo G, Rodriguez-Chavez IR; Women's Interagency HIV Study 

Collaborative Study Group, Margolick JB; Multicenter AIDS Cohort Study

 (MACS), Golding H. HIV-Selectest enzyme immunoassay and rapid test: 

ability to detect seroconversion following HIV-1 infection. 

J Clin Microbiol. 2010 Jan;48(1):281-5. Epub 2009 Nov 11. 

PubMed PMID: 19906903;

PubMed Central PMCID: PMC2812287.