Innate immunity is induced when pathogen-associated molecular patterns (PAMPs) bind host pattern recognition receptors (PRRs). Polyinosinic:polycytidylic acid [poly(I:C)] is a synthetic analogue of viral dsRNA that acts as a PAMP, inducing type I interferons (IFNs) in vertebrates. In the present study, the immunostimulatory effects of high molecular weight (HMW) poly(I:C) in rainbow trout cells were measured when bound to a cationic phytoglycogen nanoparticle (Nano-HMW). The physical characteristics of the nanoparticle itself, when bound to different lengths of dsRNA and when cell associated was evaluated. Optimal concentration and timing for innate immune stimulation was measured using the RTG-P1 reporter cell line. The immunostimulatory effects of HMW poly (I:C) was compared to Nano-HMW in vitro using the RTgutGC cell line cultured in a conventional monolayer or a transwell culture system. The ability of an activated intestinal epithelium to transmit an antiviral signal to macrophages was evaluated using a co-culture of RTgutGC cells and RTSll (a monocyte/macrophage cell). In all culture conditions, Nano-HMW was a more effective inducer of IFN-related antiviral immune responses compared to HMW poly (I:C) alone. This study introduces the use of cationic phytoglycogen nanoparticles as a novel delivery system for immunomodulatory molecules to enhance immune responses in aquatic vertebrates.

No abstract

No abstract

Significance and Impact of the Study: Biofilms confer increased persistence and recalcitrance of microbial life. Confoundingly, agents which combat these protective structures may promote their growth. Functionalized phytoglycogen (FP), a 'nano by nature' polymer extractable from sustainable sources and offering benefits over conventional nanoparticles, substantively reduced biofilms and prevented increased biofilm formation in response to suboptimal antibiotic concentrations. For the first time, we show antibiotic treatment of pregrown biofilms drives proliferation, whereas FP-antibiotic combinations reduced growth. Swimming, swarming and twitching motility, all associated with biofilm development, were negatively affected by FP. The use of novel polymers to enhance antibiotic performance opens new pathways in antibiotic research.