[MARMAM] New publications: Silver Nanoparticles (AgNPs) induce Th2 cytokin bias on dolphin leukocytes

Wen-Ta Li heerolee1104 at gmail.com
Sat Sep 29 20:34:55 PDT 2018


Dear MARMAM,

My co-authors and I are pleased to announce the new publication of the
following article in PeerJ.

*Th2 cytokine bias induced by silver nanoparticles in peripheral blood
mononuclear cells of common bottlenose dolphins (Tursiops truncatus)*

*Background*
Silver nanoparticles (AgNPs) have been widely used in many commercial
products due to their excellent antibacterial ability. The AgNPs are
released into the environment, gradually accumulate in the ocean, and may
affect animals at high trophic levels, such as cetaceans and humans, via
the food chain. Hence, the negative health impacts caused by AgNPs in
cetaceans are of concern. Cytokines play a major role in the modulation of
immune system and can be classified into two types: Th1 and Th2. Th1/Th2
balance can be evaluated by the ratios of their polarizing cytokines (i.e.,
interferon [IFN]-γ/Interleukin [IL]-4), and animals with imbalanced Th1/Th2
response may become more susceptible to certain kinds of infection.
Therefore, the present study evaluated the in vitro cytokine responses of
cetacean peripheral blood mononuclear cells (cPBMCs) to 20 nm citrate-AgNPs
(C-AgNP20) by quantitative reverse transcriptase polymerase chain reaction
(qRT-PCR).
*Methods*
Blood samples were collected from six captive common bottlenose
dolphins (*Tursiops
truncatus*). The cPBMCs were isolated and utilized for evaluating the in
vitro cytokine responses. The cytokines evaluated included IL-2, IL-4,
IL-10, IL-12, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α. The
geometric means of two housekeeping genes (HKGs), glyceraldehyde
3-phosphate dehydrogenase (GAPDH) and β2-microglobulin (B2M), of each
sample were determined and used to normalize the mRNA expression levels of
target genes.
*Results*
The ratio of late apoptotic/necrotic cells of cPBMCs significantly
increased with or without concanavalin A (ConA) stimulation after 24 h of
10 µg/ml C-AgNP20 treatment. At 4 h of culture, the mRNA expression level
of IL-10 was significantly decreased with 1 µg/ml C-AgNP20 treatment. At 24
h of culture with 1 µg/ml C-AgNP20, the mRNA expression levels of all
cytokines were significantly decreased, with the exceptions of IL-4 and
IL-10. The IFN-γ/IL-4 ratio was significantly decreased at 24 h of culture
with 1 µg/ml C-AgNP20 treatment, and the IL-12/IL-4 ratio was significantly
decreased at 4 or 24 h of culture with 0.1 or 1 µg/ml C-AgNP20 treatment,
respectively. Furthermore, the mRNA expression level of TNF-α was
significantly decreased by 1 µg/ml C-AgNP20 after 24 h of culture.
*Discussion*
The present study demonstrated that the sublethal dose of C-AgNP20 (≤1
µg/ml) had an inhibitory effect on the cytokine mRNA expression levels of
cPBMCs with the evidence of Th2 cytokine bias and significantly decreased
the mRNA expression level of TNF-α. Th2 cytokine bias is associated with
enhanced immunity against parasites but decreased immunity to intracellular
microorganisms. TNF-α is a contributing factor for the inflammatory
response against the infection of intracellular pathogens. In summary, our
data indicate that C-AgNP20 suppresses the cellular immune response and
thereby increases the susceptibility of cetaceans to infection by
intracellular microorganisms.

*You can have the article in https://peerj.com/articles/5432/
<https://peerj.com/articles/5432/> **or by email: heerolee1104 at gmail.com
<heerolee1104 at gmail.com>*

Cheers,

Wen-Ta
-- 
Wen-Ta Li, DVM, PhD
Veterinary Pathologist, Graduate Institute of Molecular and Comparative
Pathobiology, National Taiwan University
Veterinarian/Director, Taiwan Cetacean Society
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