IVD of Human Immunodeficiency Virus Type 2

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    Human Immunodeficiency Virus Type 2 (HIV-2)

    HIV is a lentivirus of the retroviridae family that can attack and destroy the human immune system, leading to the epidemic of AIDS. Patients usually experience systemic symptoms, including persistent fever, extreme fatigue, and recurrent headaches. Based on genetic and antigenic variation, HIV is divided into two categories: HIV-1 and HIV-2. Compared with HIV-1, HIV-2 has lower toxicity, longer incubation period, and lower rates of sexual transmission and mother-to-child transmission. Since HIV cannot be cured, in vitro diagnostics (IVD) can quickly determine the infection status and prompt patients to seek medical treatment.

    Figure 1. The life cycle of HIV. (Masenga S K, et al., 2023)

    Main Methods of IVD for HIV2

    • Serological testing for HIV-2 antibodies.
    • Specific immunoblot tests such as western blot (WB).
    • Specific enzyme immunoassay (EIA), enzyme-linked immunosorbent assay (ELISA), and chemiluminescence immunoassay (CLIA).
    • Virological detection of HIV-2 DNA or RNA. RT-PCR technology is mainly used to detect HIV-2 RNA.
    • Gold standard method (test paper detection). By using immunocolloidal gold technology, gold-labeled antibodies bind to HIV-2 antigens in urine to produce a specific color reaction to determine whether it is positive.
    • Protein chip

    Creative BioMart can provide high-quality recombinant HIV-2 antigens used for IVD, including ELISA, lateral flow assays, western blots, and other immunoassays.

    Highlights of Our Products

    • Completed biological functions and efficient activity.
    • High sensitivity, high specificity, and high purity.
    • A wide range of immune tests are available, such as ELISA, lateral flow, WB, and others.
    • Easy to store and transport, conducive to large-scale production and use of vaccines.
    • Outstanding success rate and fast development speed.

    Our Outstanding Advantages

    • With a professional R&D team and advanced laboratory facilities, we can conduct a variety of production research and development.
    • Strict quality control can ensure product stability and reliability.
    • A complete IVD protein platform can provide customized services to meet different scientific research needs.
    • High-quality service, high-level experiments, and reliable analysis.
    • IVD proteins can be used to test for a variety of diseases and conditions, making them valuable tools for diagnosing and monitoring health.

    In addition, Creative BioMart also offers a series of viral proteins and protein-related services to provide customers with high-quality, low-cost active recombinant proteins to meet different needs and assist in preclinical drug development.

    Case Study

    Case 1: Palm AA, Lemey P, Jansson M, Månsson F, Kvist A, Szojka Z, Biague A, da Silva ZJ, Rowland-Jones SL, Norrgren H, Esbjörnsson J, Medstrand P. Low Postseroconversion CD4+ T-cell Level Is Associated with Faster Disease Progression and Higher Viral Evolutionary Rate in HIV-2 Infection. mBio. 2019 Jan 8;10(1):e01245-18. doi: 10.1128/mBio.01245-18. PMID: 30622192; PMCID: PMC6325243.

    A positive correlation between virus evolutionary rate and disease progression has been shown for human immunodeficiency virus type 1 (HIV-1) infection. Much less is known about HIV-2, the second causative agent of AIDS. Researchers analyzed 528 HIV-2 env V1-C3 sequences generated from longitudinal plasma samples that were collected from 16 study participants during a median observation time of 7.9 years (interquartile range [IQR], 5.2 to 14.0 years). he HIV-2 evolutionary rate was significantly associated with CD4+ T-cell levels and was almost twice as high among the faster progressors as among the slower progressors. Higher evolutionary rates were accounted for by both synonymous and nonsynonymous nucleotide substitutions. Moreover, slow disease progression was associated with stronger positive selection on HIV-2/SIVsm (simian immunodeficiency virus infecting sooty mangabey) surface-exposed conserved residues.

    Fig2. Codon-specific selective pressure. The selective pressures at each codon site of the sequence alignment of the env V1-C3 region of HIV-2 for faster and slower disease progressors are indicated. The proportions (y axis) with positive selection (vermillion or blue) or negative selection (gray) at codon sites of the sequence alignment (x axis) are shown for faster progressors (upper graph) and slower progressors (lower graph). Filled black circles indicate codons conserved between HIV-2/SIVsm strains associated with positive selection. Vertical lines divide the fragment into env regions V1V2, C2, V3, and C3.

    Case 2: Weiss RA. Getting to know HIV. Trop Med Int Health. 2000 Jul;5(7):A10-5. doi: 10.1046/j.1365-3156.2000.00591.x. PMID: 10964277.

    Our knowledge of the cellular tropism and cell surface receptors exploited by the virus help to explain the pattern of immune deficiency, wasting and dementia that make up the clinical dimensions of AIDS. The extraordinary rate of genetic and phenotypic evolution of the virus - both within the infected individual and across the worldwide pandemic - partially explains why no vaccine constructs to date have been successful. HIV comprises just 9 genes but represents one of humanity's most formidable foes.

    Fig3. Genomic organization of HIV-1 and HIV-2. The long-terminal repeats (LTR) control integration and gene expression. The genes are shown in their respective reading frames. The scale is in kilobases of proviral DNA. (Adapted from J. Reeves, PhD Thesis, University of London, 2000).

    Case 3: Strappe PM, Hampton DW, Brown D, Cachon-Gonzalez B, Caldwell M, Fawcett JW, Lever AM. Identification of unique reciprocal and non-reciprocal cross packaging relationships between HIV-1, HIV-2 and SIV reveals an efficient SIV/HIV-2 lentiviral vector system with highly favourable features for in vivo testing and clinical usage. Retrovirology. 2005 Sep 16;2:55. doi: 10.1186/1742-4690-2-55. PMID: 16168051; PMCID: PMC1253535.

    This study investigates the packaging relationship between gene transfer (vector) and Gag-Pol expression constructs of HIV-1, HIV-2 and SIV. Cross-packaged vectors expressing GFP were assessed for RNA packaging, viral vector titre and their ability to transduce rat primary glial cell cultures and human neural stem cells.

    This new non-reciprocal cross packaging relationship between SIV and HIV-2 provides a novel way of significantly increasing bio-safety with a reduced sequence homology between the HIV-2 gene transfer vector and the SIV Gag-Pol construct thus ensuring that vector RNA packaging is unidirectional.

    Fig4. Transduction of rat mixed glial cells with a HIV-2 based lentiviral vector packaged by SIV gag-pol. (A) GFP expression in lentivector transduced cells. (B) GFAP co-staining of astrocytes.

    Reference

    • Masenga S K, Mweene B C, Luwaya E, et al. (2023). HIV–Host Cell Interactions[J]. Cells. 12(10): 1351.