Anti-IL10 monoclonal antibody, clone JES3-12G8 [Biotin]

Benzo[a]pyrene (BaP) is one of the most well studied carcinogenic polycyclic aromatic hydrocarbons (PAHs) that has been associated with a wide range of toxic effects in aquatic organisms. In the present study, the mosquitofish and zebrafish were exposed to BaP (100 mu g/L) for 15 days. We analyzed the intestinal microbial community of mosquitofish and zebrafish using 16S rRNA gene amplicon sequencing and also performed transcriptional profiling of the inflammation pathway related genes in the intestinal tissues. Our results showed that BaP exposure induced similar changes to the composition of microbial community in mosquitofish and zebrafish. At the phylum level, the abundance of Proteobacteria decreased while the abundance of Firmicutes increased following BaP exposure. At the genus level, a common pathogenic genus staphylococcus significantly increased in the BaP treatment groups, compared to the control (DMSO, similar to 0.001% v/v). In addition, it was observed that BaP significantly increased the mRNA level of il1 beta in both mosquitofish and zebrafish. The transcript levels of il6, il8, il10 and ifnphi1 were significantly increased in zebrafish, however not in mosquitofish, following Bap exposure. Our findings suggest that BaP could induce microbiota dysbiosis and inflammation in the intestine of mosquitofish and zebrafish.

Interleukin (IL)-10 is a critical anti-inflammatory and late cytokine being produced after the proinflammatory mediators while IL-6 is a promptly synthesized cytokine in response to inflammation in mammals. This chronological expression of interleukin (Il)-6 and Il-10 was also found in grass carp head kidney leucocytes (HKLs) treated by heat-killed Aeromonas hydrophila, supporting the possible interplay between grass carp (gc)Il-6 and gcIl-10 in HKLs. Our further findings were in agreement with this hypothesis that recombinant gcIl-6 (rgcIl-6) promptly and transiently increased gcil10 mRNA levels in grass carp HKLs. Moreover, rgcIl-6 enhanced its own mRNA level and this self-enhancement of gcil6 mRNA level could be partially blocked by rgcIl-10. These results collectively suggest that gcIl-10 production stimulated by gcIl-6 may provide a negative feedback to gcIl-6 production. Interestingly, rgcIl-6 significantly decreased gcil10 mRNA levels in grass carp HKLs after the treatment for 12 and 24 h in contrast to its enhancement of gcil10 levels after the treatment for 3 h. Involvement of Stat3 but not MEK, p38 MAPK or JNK pathway in the increase of gcil10 mRNA levels by rgcIl-6 was revealed by using the signaling pathway inhibitors. This was supported by the fact that rgcIl-6 stimulated Stat3 phosphorylation in grass carp HKLs. Furthermore, rgcIl-6 had no effect on the stability of gcil10 mRNA after the treatment for 3 to 36 h while it increased gcil10 promoter activity after the treatment for 24 h. Taken these data together, gcIl-6 can stimulate Il-10 production at early stage but subsequently inhibit il10 mRNA expression in grass carp HKLs, shedding light on the dynamic regulation of il10 mRNA expression by Il-6 in fish immune cells.