Comparison of MagPix Assays and Enzyme-Linked Immunosorbent Assay for Detection of Hemorrhagic Fever Viruses

Abstract

Viral hemorrhagic fevers, because of their high mortality rates, the lack of medical countermeasures, and their potential use as instruments of bioterrorism, pose a significant threat to the developed and the developing areas of the world. The key to preventing the spread of these diseases is early and accurate detection. For decades, the gold-standard immunoassay for hemorrhagic fever detection has been the enzyme-linked immunosorbent assay (ELISA); however, newer technologies are emerging with increased sensitivities. One such technology is the Luminex MagPix platform using xMAP microspheres. Here, we compare the MagPix platform with a traditional ELISA for IgM and antigen detection of infections from Lassa and Ebola viruses (LASV and EBOV, respectively). For IgM detection in nonhuman primate samples, the MagPix platform was 5 and 25 times more sensitive in detecting LASV and EBOV, respectively, compared to that with ELISA. For antigen detection in buffer, the MagPix platform was 25 and 2.5 times more sensitive in detecting lower levels of LASV and EBOV, respectively. In both IgM and antigen detection assays, the MagPix platform demonstrated excellent reproducibility at the lower limit of detection (LLOD). These findings demonstrate that the MagPix platform is a viable diagnostic replacement for the ELISA for viral hemorrhagic fevers.KEYWORDS ELISA, MagPix, Ebola virus, immunoassays, Lassa virus, viral hemorrhagic fever H emorrhagic fevers are a part of the normal disease burden in Africa. In the developed world, they are a concern because of their potential use as bioterrorism agents. Lassa virus (family, Arenaviridae) and ebolaviruses (family, Filoviridae) are hemorrhagic fever viruses that are endemic in several African countries (1, 2). Disease outbreaks with these viruses have significant medical and social impacts. Case fatality rates can be as high as 65% for Lassa virus (LASV) and as high as 90% for ebolaviruses (3,4). Their high mortality rates combined with their ease of transmission and the lack of vaccines or effective treatments render them extremely dangerous pathogens.Early during an infection, hemorrhagic fever viruses have a clinical presentation that is similar to other more common febrile illnesses (5, 6). A rapid and accurate diagnosis of hemorrhagic fever viruses is critical for limiting the spread of disease and enabling an earlier more effective treatment. Traditionally, enzyme-linked immunosorbent assays (ELISAs) have been used for the detection of a virus-specific antigen and/or IgM antibodies (7,8).ELISA immunodiagnostics are the standard by which other diagnostics are evaluated. ELISA has been commonly used for the detection of LASV and Ebola virus (EBOV) for many years; however, newer immunodiagnostic platforms that offer multiplex

Confronting the threat of bioterrorism: realities, challenges, and defensive strategies

“…38 A system that uses a sensitive microsphere technology to detect both antibodies and antigens is now available to diagnose infections with Ebola virus and Lassa virus. 39 Although diagnostic ELISA tests are available for anthrax antibodies, 40,41 a compact system (GeneXpert) that includes both sample processing and PCR amplification can produce a result in about 90 minutes. 42 A rapid and sensitive method to detect smallpox virus has been developed for use at point of care, based on antibody immuno column for analytical processes (ABICAP) immunofiltration, that produces results in about 45 minutes.…”

Virus-Like Particles and Magnetic Microspheres Provide a Flexible and Sustainable Multiplexed Alphavirus Immunodiagnostic Platform

“…One such system is the MAGPIX® developed by Luminex Corporation (Austin, Texas USA) (16). It is similar to ELISA in that it detects a typical antigen/antibody interaction, but by employing fluorescently labeled magnetic particles as a solid support, MAGPIX assays are much faster, have increased sensitivity, and better enable multiplexing (17, 18). This ability to multiplex while maintaining assay sensitivity is crucial for effective serosurveillance efforts to understand and control the spread of disease.…”

Laboratory Diagnosis of Lassa Fever

“…Satterly and colleagues recently described transitioning Lassa and Ebola virus antigen-and IgM-based ELISAs onto a MAGPIX system (53) that uses individually labeled magnetic beads to detect multiple targets in a single assay. This assay has lower limits of detection for Lassa virus nucleoprotein and IgM than traditional ELISAs (53). The same group also developed and tested a multiplex MAGPIX IgG assay for a wide spectrum of hemorrhagic fever viruses, including alphaviruses, arenaviruses, flaviviruses, and filoviruses (14).…”

“…Multiple antigen and IgM capture ELISAs have been developed using inactivated virus (36,(52)(53)(54); however this approach is limited to BSL-4 capable facilities. The use of recombinant antigens allows for improved assay development and access (50, 55-57).…”