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Research tools and Drug Discovery Service

in Antiviral research


XpressBio has developed ELISA Core Antigen Detection kits as tools for a use in in vitro and animal models, as well as in Vaccine Development. We have kits for HCV, HIV p24 and SIV p27 detection.

We also offer a unique kit for HIV-1 integrase and a screening service for Integrase Inhibitor Drug Candidates.

HCV cell culture antigen ELISA
Hepatitis C


According to a study*, chronic liver disease is a leading cause of human mortality. Hepatitis B and C are responsible for 71 percent of liver cancer deaths and 58 percent of cirrhosis deaths, whereas alcohol is responsible for 25 percent of all deaths caused by liver cancer and cirrhosis. The toll taken by hepatitis B and C differs by region with hepatitis C causing a greater number of deaths in the U.S. and Western Europe, and hepatitis B causing more deaths in China and India.


BC Cowie and JH MacLachlan. The global burden of liver disease attributable to hepatitis B, hepatitis C, and alcohol: increasing mortality, differing causes.64th Annual Meeting of the American Association for the Study of Liver Diseases (AASLD 2013). Washington, DC, November 1-5, 2013. Abstract23.


HIV cell culture antigen p24 SIV p27 ELISA


In 2012*, an estimated:

  • 35.3 million [32.2 million - 38.8 million] people globally were living with HIV;

  • 2.3 million [1.9 million - 2.7 million] people became newly infected with HIV;

  • 1.6 million [1.4 million - 1.9 million] people died from AIDS-related illnesses.


*UNAIDS. Report on the Global AIDS Epidemic.2013.

HIV-1 integrase screening inhibitors
HIV-1 Integrase Assay and Service


Integrase Inhibitors are a class of drugs which target the HIV enzyme integrase. This is the enzyme responsible for the integration of viral genetic material into human DNA, a crucial step in the replication cycle of HIV.


Integrase inhibitors targets the step of insertion into the host’s DNA. There are three phases of integrase activity. First, the integrase binds the cell’s DNA. Next, it prepares the viral DNA for integration by slightly altering its DNA to prepare it for insertion. Then the processed DNA is inserted into the host cell, which is now altered to make virus particles.


The original research on developing integrase inhibitors was not successful, but it primarily targeted the first two steps. The first FDA approved Integrase Inhibitor Raltegravir targets the third step. With integration into the host cell blocked, the virus cannot spread.

Reverse Transcriptase Assay


Human Immunodeficient Virus 1 (HIV 1) is a retrovirus that contains, as part of its genome, a reverse transcriptase (RT) gene, that when translated into protein, reverse transcribes HIVs RNA genome into a transducing DNA copy (cDNA). This HIV RT activity is critical during early viral infection. HIV 1 infection results in host cell domination, viral replication, and host cell death. HIV RT is an optimistic target for blocking the virus life cycle and the spread of the virus to neighboring cells. In addition, HIV RT in viral conditioned medium directly correlates with virus propagation in cell-mediated in vitro experimental model systems, therefore HIV RT activity can be used as a marker for HIV 1 growth.

XpressBio has developed a 2-hour HIV RT assay for drug screening and a 24-hour assay to detect as little as 1 pg of HIV RT in viral conditioned media. An assay incubation time of 5-6 hours allows the experiment to be completed in one day and will detect 2 pg of HIV RT. The RT assay is qualitative, non-radioactive, colorimetric, and can be used to determine if test articles, compounds, or peptides can inhibit HIV RT activity. The assay can also be used to quantitate HIV RT activity in experimental samples.

The HIV RT Assay Kit can be used to detect other retroviruses including HIV-2, M-MuLV, AMV, and SIV-1.

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