Quantitation of cytopathic honey bee viruses using the viral plaque assay method

Authors: MCMENAMIN, ALEXANDER - Orise Fellow; Goblirsch, Michael

Submitted to: Journal of General Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/2026
Publication Date: 7/28/2026
Citation: Mcmenamin, A., Goblirsch, M.J. 2026. Quantitation of cytopathic honey bee viruses using the viral plaque assay method. Journal of General Virology. 107. https://doi.org/10.1099/jgv.0.002304.
DOI: https://doi.org/10.1099/jgv.0.002304

Interpretive Summary: Viral infections are common in honey bee hives globally and there is evidence that these pathogens are spread among other pollinators via sharing of floral resources and other interactions. Furthermore, many of these viruses are exchanged between individual honey bees and between honey bee hives via parasitic mites, which can serve as a viral vector. The negative effects of viral infections on honey bees include a decrease in survival of infected individuals and weakening of the hive that could lead to premature hive death. To enhance our understanding of honey bee viruses, especially at the cellular level, basic techniques in virology could be applied to honey bee cell culture systems. Here we used one such technique, the tried-and-true viral plaque assay with the continuous honey bee cell line, AmE-711. To optimize the technique for use with AmE-711 cells, we compared plaque count, size, and shape using two traditional overlays, agarose and carboxymethyl cellulose (CMC). We found that the CMC overlay was superior in producing countable plaques of uniform size and we were able to determine infection intensity and directly quantify infectious viral units using the bee-specific virus, Acute bee paralysis virus (ABPV). Lastly, we demonstrate that the plaque assay was useful in quantifying infectious virus from whole honey bee pupae infected with ABPV, promoting the method's utility with field-relevant samples.

Technical Abstract: Viral pathogens are highly prevalent threats to our pollination workforce. Basic virological techniques for ascertaining infection intensity and quantifying infectious viral particles lag behind the research interest in pollinator-associated viruses. Here, we utilized the only available immortalized honey bee (Apis mellifera) cell line, AmE-711, to establish the first plaque assay protocol for a bee-infecting virus in honey bee cells. We compared two traditional overlays, agarose and carboxymethyl cellulose (CMC), and found that the CMC method was superior in producing countable plaques. Lastly, we demonstrate that this method was useful in quantifying infectious particle loads in lysates derived from whole honey bee pupae infected with Acute bee paralysis virus, a field-relevant sample type.