Posted by Adam Awdish on
Pooled Human Serum Off The Clot from Innovative Research was used in the following study:
Derrick Hau,Brian Wade, Chris Lovejoy, Sujata G. Pandit, Dana E. Reed, Haley L. DeMers, Heather R. Green, Emily E. Hannah, Megan E. McLarty, Cameron J. Creek, Chonnikarn Chokapirat, Jose Arias-Umana, Garett F. Cecchini, Teerapat Nualnoi, Marcellene A. Gates-Hollingsworth, Peter N. Thorkildson, Kathryn J. Pflughoeft, David P. AuCoin
March 23, 2022
Yersinia pestis is a gram-negative bacterium that is the cause for plague in mammals, presenting itself in three distinct forms. Specifically, the fatality rates of the pneumonic and septicemic forms of plague are nearly 100% when not quickly diagnosed and treated. The third form, the bubonic form, has a fatality rate of 40-70% on its own, however, if left untreated it may develop into one of the more serious forms. Y. pestis is primarily transmitted via flea bites or close contact with an infected host, and the CDC classifies the bacterium as a Tier 1 Select Agent because of its high rate of infection, mortality rate, threat level to public health, and potential as I biological threat to society.
Currently, the most common method for diagnosing plague relies on bacterial cultures. Serum samples from patients can be tested for the presence of antigens, however, diagnosis of an active infection can be timely as any patient who had the infection in the past will have antibodies that can trigger an initial false positive. This, combined with the specialized equipment and training needed to use it, can make the analysis of serum costly and time consuming.
In one study that compared different diagnostic methods for detecting plague LFIs were found to be the ideal method for testing. LFIs are rapid-working immunoassays that use antibodies linked to nanoparticles to visually detect a target. LFIs were thus developed for the diagnosis of plague, and current models focus on detection of an F1 protein unique to Y. pestis. However, there have been mutant strains of Y. pestis detected in clinical and lab settings that do not express the F1 pilus structure, essentially making their detection unreliable on current LFI models.
Another study observing mice infected with the plague found that a different antigen displayed on the surface of Y. pestis., LcrV, was detectable in the serum and bronchoalveolar lavage fluid (BALF) of the infected mice. LcrV is essential for pathogenicity and seems to be shed during infection of the host, making it a viable alternative to F1 as a biomarker used for diagnosing plague.
Researchers in this study isolated 22 high-affinity mAbs from BALB/c mice immunized with recombinant LcrV, F1 and F1-LcrV fusion protein. These mAbs were then used to develop prototype immunoassays for plague diagnosis and characterized by Western blots, ELISA, and surface plasmon resonance. They were then used to produce LFIs and ELISAs, and then a novel multiplexed LFI was developed to detect both LcrV and F1. The prototype was tested against a panel of multiple Y. pestis isolates and could be promising for future effective diagnosing of plague.
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