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Dispatch
Infection of Cultured Human
and Monkey Cell Lines with Extract of Penaeid Shrimp Infected with Taura
Syndrome Virus
Josefina Audelo-del-Valle,* Oliva Clement-Mellado,† Anastasia Magaña-Hernández,†
Ana Flisser,‡ Fernando Montiel-Aguirre,‡ and Baltasar Briseño-García†
*Universidad de Occidente, Los Mochis, Sinaloa, México; †Instituto de
Diagnóstico y Referencia Epidemiológicos, México, D.F., México; and ‡Universidad
Nacional Autónoma de México, México, D.F., México
Suggested citation for this article: Audelo-del-Valle
J, Clement-Mellado O, Magaña-Hernández A, Flisser A, Montiel-Aguirre
F, Briseño-García B. Infection of cultured human and monkey cell lines
with extract of penaeid shrimp with taura syndrome virus. Emerg Infect
Dis [serial online] 2003 Feb [date cited]. Available from: URL:
http://www.cdc.gov/ncidod/EID/vol9no2/02-0181.htm
Taura syndrome virus
(TSV) affects shrimp cultured for human consumption. Although TSV is
related to the Cricket Paralysis virus, it belongs to the “picornavirus
superfamily,” the most common cause of viral illnesses. Here we demonstrate
that TSV also infects human cell lines, which may suggest that Penaeus
is a potential reservoir of this virus.
The Taura syndrome virus (TSV) causes a disease affecting penaeid shrimp,
the most important commercial family of crustaceans (1).
The causal agent is a single-stranded (+) RNA virus, recently reported
to be genomically related to the Cricket Paralysis virus of the Cripavirus
genus, family Dicistroviridae of the “picornavirus superfamily”
(2-5). This superfamily includes several human pathogens,
for example, the common cold viruses and several enteroviruses (e.g.,
polioviruses). Traditionally, research on the replication of shrimp viruses
has been based on the use of cultured fish cellular lines (6).
However, because TSV could potentially represent a public health threat,
we explored whether this viral agent might be capable of infecting cultured
mammalian cells.
The Study
Since Sabin strain LSc 2ab (Sabin 1), the poliovirus used for human
vaccination, is usually replicated in monolayer culture cells of human
rhabdomyosarcoma (RD), human larynx carcinoma (Hep-2C), or Buffalo green
monkey kidney (BGM) (7), we injected these cell lines
with a 0.22-µm membrane-filtered whole extract of the hepatopancreas of
shrimp (Penaeus stylirostris) affected with TSV. The animals were
collected from farms located in northwestern Mexico. Control cell lines
were injected with filtered hepatopancreas extracts from healthy shrimp.
Cultures were incubated at 37°C and periodically observed under a microscope
until any sign of cytopathic effect was detected (usually from 19–23 hours).
Cells were then harvested and lysed. Fresh cell lines were inoculated
with the lysate, incubated, and processed in a similar way. A third inoculation
was again performed with the second lysate (8).
The cytopathic effect in RD cells began with a partial destruction of
the cellular layer. Next, small cellular groups and some isolated round
cells were observed. The cells showed an apparent increase in size, diffuse
cell rounding, and a refringent aspect (Figure 1B).
In Hep-2C cells, the cellular monolayer was partially destroyed. Most
cells were individualized and clearly rounded; they also presented a refringent
aspect. Hep-2C was the most affected of the three lines used (Figure
1D). The cytopathic effect in the BGM cell line began as a partial
destruction of the cellular layer, which evolved to a syncytial-like formation
of rounded, refringent cells. Some cells remained isolated but with altered
morphology (Figure 1F). RD, Hep-2C, and BGM cells
injected with an extract similarly processed but from healthy shrimp,
showed no cytopathic effects, even after 7 days of culture (Figures
1A, 1C, and 1 E). As a positive control, RD cells were injected with
Sabin viral extract and showed the characteristic cytopathic effect produced
by an enterovirus infection.
To confirm the presence of TSV in the cell culture media, a bioassay
was performed by using media from the third passage. For this assay, healthy
P. stylirostris shrimp were injected with the infected medium in
10% volume of their corporal mass in the third abdominal segment. Twenty-four
hours later, these animals were clearly infected, showing fragile antennas
and soft cuticle as well as chromatophore expansion along the whole surface
of the body, particularly at the tail fan (telson and uropods). These
signs were clinically indistinguishable from those occurring in naturally
infected animals and are considered as pathognomonic of the acute phase
of infection by TSV (9). Presence of the viral genome
in different subcuticular tissues (gills and pleopods) of these animals
was confirmed by in situ hybridization by using TSV ShrimProbe (DiagXotics,
Inc., Wilton, CT). RNA-DNA hybrids were clearly visible as black spots
after the samples were stained with Bismarck brown (Figure
2). Shrimp injected with culture media from control cell lines showed
no signs of infection after 7 days of observation.
Conclusions
If one takes into consideration the capacity of viruses to modify receptor
recognition and host cell tropism and the fact that cell receptors for
many of the picornavirus superfamily members seem to be ubiquitous membrane
molecules (e.g., decay-accelerating factor, different type of integrins,
low-density lipoprotein receptor, sialic acid [10-12]),
the potential wide range of host cells for TSV should not come as a surprise.
To our knowledge, these cultured human and monkey cell lines are the first
reported to be infected with a viral agent isolated from shrimp. Because
many members of the picornavirus superfamily are the most common causes
of viral illnesses worldwide (including nonspecific febrile illnesses,
myocarditis, aseptic meningitis, and sepsis-like disease), such illnesses
lead to frequent unnecessary prescription of antibiotics (13).
Penaeus could be considered as a reservoir of a virus that could
become a potential pathogen to humans and other mammals (11,14).
Acknowledgments
We gratefully acknowledge Dolores Correa and Mirza Romero
for helpful and critical discussions.
Ms. Audelo-del-Valle is a fisheries biologist and lecturer
at the Universidad de Occidente, Campus Los Mochis, Sinaloa, México.
She founded and directs the Molecular Biology Aquaculture Laboratory
in the Universidad de Occidente and is currently a Ph.D. candidate.
References
- Food and Agricultural Organization. Aquaculture production
statistics 1987–1996. Rome: The Organization; 1998.
- Bonami JR, Hasson KW, Mari J, Poulos BT, Lightner DV. Taura
syndrome of marine penaeid shrimp: characterization of the viral agent.
J Gen Virol 1997;78:313–9.
- Mari J, Poulos BT, Lightner DV, Bonami JR. Shrimp
Taura syndrome virus: genomic characterization and similarity with members
of the genus Cricket paralysis-like viruses. J Gen Virol
2002;83:915–26.
- Robles-Sikisaka R, Garcia DK, Klimpel KR, Dhar AK. Nucleotide sequence
of 3´-end of the genome of Taura syndrome virus of shrimp suggests that
it is related to insect picornaviruses. Arch Virol 2001;146:941–52.
- van Regenmortel MHV, Fauquet CM, Bishop DHL, Cartens EB, Estes MK,
Lemon SM et al., editors. In: Virus taxonomy: seventh report of the
International Committee on Taxonomy of Viruses. San Diego: Academic
Press, 2000.
- Loh PC, Tapay LM, Lu Y, Nadala ECB Jr. Viral
pathogens of the penaeid shrimp. Adv Virus Res 1997;48:263–312.
- Ashkenazi A, Melnick JL. Enteroviruses: a review of their properties
and associated diseases. Am J Clin Pathol 1962;38:209–29.
- Mahy BWJ, Kangro HO. Virology methods manual. London: Academic Press,
Ltd.; 1996.
- Hasson KW, Lightner DV, Poulos BT, Redman RM, While BL, Brock JA,
et al. Taura syndrome in Penaeus vannamei: demonstration of a
viral etiology. Dis Aquat Organ 1995;23:115–26.
- Evans DJ, Almond JW. Cell
receptors for picornaviruses as determinants of cell tropism and pathogenesis.
Trends Microbiol 1998;6:198–202.
- Baranowski E, Ruiz-Jarabo CM, Domingo E. Evolution
of cell recognition by viruses. Science 2001;292:1102–5.
- Rossmann MG, He Y, Kuhn RJ. Picornavirus-receptor
interactions. Trends Microbiol 2002;10:324–31.
- Rotbart HA, Hayden FG. Picornavirus
infections. A primer for the practitioner. Arch Fam Med 2000;9:913–20.
- Weiss RA. The Leeuwenhoek Lecture 2001. Animal origins of human infectious
disease. Phil Trans R Soc Lond B 2001;356:957–77.
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