Using Proven Detection Reagents for COVID-19 Research

The recent SARS-CoV-2 pandemic has raised many questions regarding how this novel coronavirus infects humans. We are gaining a deeper understanding of viral transmission between people and aspects that tend to make certain members of the population more susceptible to the virus. Avenues of research that hold promise in identifying which specific organs and cell types are affected include histological approaches using human tissue samples and animal models.

Immunohistochemistry, using proven materials such as the VECTASTAIN ABC reagents, was recently utilized to visualize detectable virus in several organs of an infected animal host and ACE2/TMPRSS2 in ocular and other cell types [1, 2, 3, 9, 10, 14, 15]. These studies helped confirm the extent to which the virus spreads throughout the body and provides data regarding cellular localization of the virus.

Other investigators are exploiting new techniques in cell culture such as 3D organoids to investigate infection routes of coronaviruses. This approach relies primarily on immunofluorescent visualization. Studies by Zhou et al [4] and more recently Lamers et al [5] and Monteil et al [6] utilized human organoids to show both Middle East respiratory syndrome (MERS) coronavirus and SARS-CoV-2 infect gut and kidney cells. Many of these studies relied on VECTASHIELD antifade mounting media to maximize signal retention for imaging and data evaluation [16].

Further quantitative approaches can be obtained using platforms such as ELISAs. In a research article by Wang et al [7], which forewarned of future pandemics with coronaviruses, the authors made a library of neutralizing monoclonal antibodies for developing possible prevention and therapeutic interventions for viral infection. Part of their study involved the detection of biotinylated antibodies using peroxidase conjugated avidin (Catalog Number A-2014) in an ELISA assay to assess competition binding to a coronavirus spike protein. Other investigators are staining non-neuronal cells in the olfactory bulb to investigate anosmia, one known symptom of COVID-19 [8].

The importance of using established, reliable and reproducible detection reagents cannot be understated for any research endeavor. It seems this point cannot be overstated with ongoing research efforts focusing on vaccines to end the current viral pandemic [13]. Vector Laboratories is proud and honored that our products have been trusted in these vital research studies.

IHC of Tissues from SARS-CoV-2-Infected Ferrets
Figure 1 from Kim et al [1]. Infection and Rapid Transmission of SARS-CoV-2 in Ferrets. Sections E-H: Control sections. Sections I-L: Specific staining and localization of virus in tissues using VECTASTAIN ABC kit.
Figure 6
Figure 6 from Zhou et al [2]. Expression and localization of TMPRSS2 in conjunctiva in post-mortem globe. Conjunctiva from three separate globes are depicted (A-B, C­-D). Staining was performed with VECTASTAIN ABC kit. 
IHC of Tissues from SARS-CoV-2-Infected Ferrets
Figure 13 from Lamers et al [3]. Immunofluorescent staining of SAR-CoV-2 infected intestinal organoids. Staining retained with VECTASHIELD antifade mounting medium.

The following citations showcase Vector Laboratories as a manufacturer of essential IHC and IF detection reagents that can be used to study SARS-CoV-2.

References:

  1. Kim, Y. et al. Infection and Rapid Transmission of SARS-CoV-2 in Ferrets. Cell Host & Microbe (2020).
  2. Cross, R. et al. Intranasal exposure of African green monkeys to SARS-CoV-2 results in acute phase pneumonia with shedding and lung injury still present in the early convalescence phase. Virology Journal (2020)
  3. Zhou, L. et al. ACE2 and TMPRSS2 are expressed on the human ocular surface, suggesting susceptibility to SARS-CoV-2 infectionThe Ocular Surface (2020).
  4. Zhou, J. et al. Human intestinal tract serves as an alternative infection route for Middle East respiratory syndrome coronavirus. Science Advances (2017).
  5. Lamers, M. M. et al. SARS-CoV-2 productively infects human gut enterocytes. Science (2020).
  6. Monteil, V. et al. Inhibition of SARS-CoV-2 Infections in Engineered Human Tissues Using Clinical-Grade Soluble Human ACE2. Cell (2020).
  7. Wang, L. et al. Importance of Neutralizing Monoclonal Antibodies Targeting Multiple Antigenic Sites on the Middle East Respiratory Syndrome Coronavirus Spike Glycoprotein To Avoid Neutralization Escape. Journal of Virology (2018)
  8. Brann, D. et al. Non-neuronal expression of SARS-CoV-2 entry genes in the olfactory system suggests mechanisms underlying COVID-19-associated anosmia. Science Advances (2020)

  9. Rathnasinghe, R. et al. Comparison of Transgenic and Adenovirus hACE2 Mouse Models for SARS-CoV-2 InfectionEmerging Microbes & Infections (2020).

  10. Kusmartseva, I. et al. Expression of SARS-CoV-2 Entry Factors in the Pancreas of Normal Organ Donors and Individuals with COVID-19 Cell Metabolism (2020).
  11. Buzhdygan, T. et al. The SARS-CoV-2 spike protein alters barrier function in 2D static and 3D microfluidic in-vitro models of the human blood–brain barrier Neurobiology of Disease (2020).

  12. Lee, A. et al. Oral SARS-CoV-2 Inoculation Establishes Subclinical Respiratory Infection with Virus Shedding in Golden Syrian Hamsters Cell Reports Medicine (2020).

  13. Seo, S. et al. Cold-Adapted Live Attenuated SARS-Cov-2 Vaccine Completely Protects Human ACE2 Transgenic Mice from SARS-Cov-2 Infection
    Vaccines (2020).
  14. Di Teodoro, G. et al. SARS-CoV-2 replicates in respiratory ex vivo organ cultures of domestic ruminant species Veterinary Microbiology (2020). 
  15. Song, E. et al. Neuroinvasion of SARS-CoV-2 in human and mouse brain Journal of Experimental Medicine (2021).
  16. Chu, H. et al. Host and viral determinants for efficient SARS-CoV-2 infection of the human lung Nature Communications (2021).