The scope of the crustacean immune system for disease control

Abstract

The culture or wild capture of marine and freshwater shellfish, including crustaceans, is without doubt a key source of protein for a burgeoning world population. Historically the expansion of aquaculture has, however, been accompanied by the increased incidence of economically significant diseases, most notably of viral and bacterial origin. Since the late 1970s great progress has been made in our understanding of the generalized protostome innate immune system. Distinct pathways, pathogen receptor proteins and effector molecules have since been identified that are not ancestral or homologous to those of the deuterostomes, including vertebrates. Within the past decade progress has accelerated with the rapid characterisation of new classes of recognition proteins, immune effectors and regulatory pathways. This paper provides a broad overview of our current understanding of invertebrate immunology, taking the crustacean decapod immune system as its focus. Recent developments in the field are described briefly and their implications and potential considered. These advances offer fundamental new insights in our efforts to understand disease in cultured populations and also to develop knowledge of environmental effects on host/pathogen interactions within a fishery context. Of course, challenges do remain, including the lack of an immortal cell line and the limited publically-available genomic resources. These are considered in this review as priorities for future research effort. With the continued application of more insightful technologies, coupled with associated investment, it is expected that the speed at which some of these issues are resolved will accelerate.

Disease will limit future food supply from the global crustacean fishery and aquaculture sectors

“…However, he also states that these approaches are considered somewhat crude and likely impose a net energetic cost to the host (see also Smith et al, 2003;Christensen et al, 2005;Hauton et al, 2007). Hauton (2012) therefore states that in an aquaculture setting, '(that this)...-blunt approach cannot serve as a global solution to the problems of commercially significant diseases'. As such, effective disease therapies can only be developed through a detailed understanding of the molecular pathways involved in immune surveillance within these hosts.…”

“…In this respect, observations of pathogen handling in wild populations may be utilised to identify markers of immune performance that could have direct relevance for application to farming situations. Hauton (2012) Specifically for the latter example, in their paper, Bartholomay et al (2012) have demonstrated that augmentation of the RNA interference (RNAi) response in shrimp to suppress virus infection and associated disease is a promising, emerging approach to shrimp virus disease control. Here, short fragments of RNA recog-nise and bind complimentary dsRNA sequences, thereby preventing specific gene expression (e.g.…”

Bacillus NP5 Improves Growth Performance and Resistance Against Infectious Myonecrosis Virus in White Shrimp (Litopenaeus vannamei) (Bacillus NP5 Meningkatkan Pertumbuhan dan Ketahanan Terhadap Infeksi Virus Myonecrosis pada Udang Putih (L. vannamei)

“…The high concentration of granular cells in the haemolymph is related to the high phenoloxidase activity and resistance to disease. Granular cells have a role in phagocytosis, encapsulation, early recognition, melanisation and coagulation in some groups, producing and secreting antimicrobial peptides, and are involved in the cytotoxic reaction (Hauton, 2012).…”

Expression patterns of two heat-shock cognate 70 genes during immune responses and larval development of the Chinese mitten crab Eriocheir sinensis

“…For example, infections with V. harveyi are known to cause extensive pathology and tissue inflammation in the gut and hepatopancreas of shrimps . Encapsulated pathogens are cleared from the circulation, and are often collected in the gills or hepatopancreas (Hauton, 2012). In this study, the EsHSC70-5 mRNA transcript was significantly upregulated in the heart and hepatopancreas as early as 12 h after challenge by V. parahaemolyticus, while the expression of EsHSC70-5 was significantly downregulated in the intestine and gills at nearly all time points compared to the controls.…”