发布: 2019年10月20日第9卷第20期 DOI: 10.21769/BioProtoc.3404 浏览次数: 4824
评审: Alka MehraKirsten A. CoprenAswad Khadilkar
Abstract
Time to AIDS infection is longer with HIV-2, compared to HIV-1, but without antiretroviral therapy both infections will cause AIDS-related mortality. In HIV-2 infection, monitoring of antiretroviral treatment (ART) efficacy is challenging since a large proportion of HIV-2-infected individuals displays low or undetectable plasma RNA levels. Hence, quantification of cellular DNA load may constitute an alternative method for monitoring ART efficacy. Moreover, sensitive HIV-2 DNA quantification protocols are also important for the characterization of the HIV-2 reservoirs, and ultimately for the development of HIV-2 cure strategies. We have developed a sensitive and robust HIV-2 DNA quantification protocol based on whole blood as DNA source, including normalization of leukocyte cell numbers using parallel quantification of the single copy porphobilinogen deaminase gene. The specificity and sensitivity of the assay was 100%. The limit of detection was 1 copy and limit of quantification was 5 copies. When applying this protocol to HIV-2 infected, it was found that HIV-2 viral DNA was detectable in individuals in whom viral RNA was undetectable or under quantification level. Thus, this method provides a sensitive approach to HIV-2 DNA viral quantification from whole blood of HIV-2 infected patients.
Keywords: HIV-2 (HIV-2)Background
Acquired immunodeficiency syndrome (AIDS) can be caused by two viruses, either human immunodeficiency virus (HIV) type 1 (HIV-1) or type 2 (HIV-2) (Azevedo-Pereira and Santos-Costa, 2016). Although these two retroviruses have similar life cycles, they differ in that HIV-2 displays lower pathogenicity, translating into longer progression time to AIDS and reduced transmissibility (Marvin et al.,2015; Azevedo-Pereira and Santos-Costa, 2016). Another distinct feature of HIV-2 is that the plasma viral RNA load of infected individuals is significantly lower, compared with those infected with HIV-1 (Berry et al., 1998; Popper et al., 1999; Andersson et al., 2000). The cellular viral DNA load in peripheral blood has, instead, been suggested to be similar between HIV-1 and HIV-2 infections (Ariyoshi et al., 1996; Popper et al., 2000; Damond et al., 2001). However, others have indicated that also the DNA load is lower in HIV-2, compared with HIV-1, infection (Gueudin et al., 2008). Overall, HIV-2 DNA load quantification studies are relatively few, and most studies have not considered a protocol for a house-keeping gene to quantify the number of cells used in the reaction (Ariyoshi et al., 1996; Gomes et al., 1999; Popper et al., 2000; Damond et al., 2001; Soares et al., 2006; Gueudin et al., 2008; Bertine et al., 2017).
Despite the fact that the estimated time to AIDS development in HIV-2 infected individuals is longer than for individuals with HIV-1, it is clear that HIV-2 will cause AIDS-related mortality without antiretroviral therapy (ART) in infected individuals with long follow-up (Esbjornsson et al., 2018). The monitoring of treatment efficacy is, however, challenging since a large proportion of ART-naïve HIV-2 infected individuals display low or undetectable plasma RNA levels (Berry et al., 1998; Popper et al., 1999; Andersson et al., 2000; Buggert et al., 2016; Honge et al., 2018). Hence, quantification of cellular DNA load may constitute an alternative method for monitoring of ART efficacy.
For simplicity, robustness and the requirement of small volumes of blood, viral DNA quantification protocols based on whole blood, as the source of DNA, are desirable. Currently there are, however, a limited number of publications where HIV-2 DNA quantification has been based on whole blood (Bertine et al., 2017), and the need for protocols combining sensitivity with robustness is still important.
In a recent study (Esbjornsson et al., 2018), we showed that both HIV-1-infected and HIV-2-infected individuals have a high probability of developing AIDS without antiretroviral treatment.
In HIV-1 infection it has been shown that viral DNA load is an independent marker of disease progression and is well correlated with the number of latently HIV-1 infected cells, that comprises the viral reservoir (Parisi et al., 2012; Rouzioux and Avettand-Fenoel, 2018). Comprehensive studies on the HIV-2 reservoirs are, however, lacking. Thus, sensitive HIV-2 DNA quantifications protocols are also important for the characterization of the HIV-2 reservoirs, and ultimately for the development of HIV-2 cure strategies. We therefore decided to develop a sensitive and robust cellular HIV-2 DNA quantification method based on whole blood as DNA source, including normalization of leukocyte numbers using parallel quantification of the single copy porphobilinogen deaminase gene (PBDG) (Raich et al., 1986; Mbisa et al., 2009).
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文章信息
版权信息
© 2019 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Szojka, Z., Karlson, S., Jansson, M. and Medstrand, P. (2019). Quantification of HIV-2 DNA in Whole Blood. Bio-protocol 9(20): e3404. DOI: 10.21769/BioProtoc.3404.
分类
微生物学 > 微生物遗传学 > DNA
分子生物学 > DNA > DNA 定量
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