Review: Immunity mechanisms in crustaceans

Abstract

Crustacean aquaculture represents a major industry in tropical developing countries. As a result of high culture densities and increasing extension of aquaculture farms, the presence of diseases has also increased, inducing economic losses. Invertebrates, which lack adaptive immune systems, have developed defense systems that respond against antigens on the surface of potential pathogens. The defense mechanisms of crustaceans depend completely on the innate immune system that is activated when pathogen-associated molecular patterns are recognized by soluble or by cell surface host proteins, such as lectins, antimicrobial, clotting, and pattern recognition proteins, which, in turn, activate cellular or humoral effector mechanisms to destroy invading pathogens. This work is aimed at presenting the main characteristics of the crustacean proteins that participate in immune defense by specific recognition of carbohydrate containing molecules, i.e. glycans, glycolipids, glycoproteins, peptidoglycans, or lipopolysaccharides from Gram-negative and Gram-positive bacteria, viruses, or fungi. We review some basic aspects of crustacean effector defense processes, like agglutination, encapsulation, phagocytosis, clottable proteins, and bactericidal activity, induced by these carbohydrate-driven recognition patterns.

Variation in Resistance to the Invasive Crayfish Plague and Immune Defence in the Native Noble Crayfish

“…Furthermore, there are recent reports on population recoveries after crayfish plague epidemics among the Turkish narrow clawed crayfish populations (Harlioğlu 2008, Kokko et al 2012, Svoboda et al 2012. These crayfish carry the infection and are commercially exploited despite the lack of a long co-evolutionary history with A. astaci.Like other invertebrates, crayfish depend on the cellular and humoral components of the innate immune system, including the prophenoloxidase enzyme system with its active form phenoloxidase (PO), the encapsulation response and antimicrobial peptides, such as those producing lytic activity, which enable them to respond to microbial surface antigens (Iwanaga & Lee 2005, Vazquez et al 2009. Cerenius et al (2003) demonstrated that an activated PO system, e.g.…”

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

“…Crustaceans can induce rapid and effective immune responses to defend themselves against most potential pathogens, and rely largely on innate immunity (Vazquez et al, 2009). The hepatopancreas, hemocytes, intestines, and gills of crustaceans are immune-associated tissues, and the hepatopancreas and hemocytes are regarded as the most important tissues involved in crustacean immunity (Jiravanichpaisal et al, 2006).…”

Hemolymph proteins in marine crustaceans

“…Recently, scygonadin, an anionic antimicrobial peptide has been isolated from seminal plasma of the mud crab Scylla serrat [9] . More recently, antilipopolysaccharide factors (ALFs), originally identified from the amoebocyte of the horseshoe crab Limulus polyphemus [10,11] have been identified from the hemocytes of several species of decapods including Fenneropenaeus chinensis [1] , Marsupenaeus japonicas [12] , Penaeus monodon [13] , Litopenaeus setiferus [14] , Pacifastacus leniusculus [15] , Carcinus maenas, Callinectes sapidus [16] , Eriocheir sinensis [17] and Scylla paramamosain [18] .…”

“…Studies on the immunity of invertebrates have been focussed on identifying defence mechanisms and biochemical pathways activated during an infection, and on identifying cell-free hemolymph and cellular factors involved in the destruction of pathogens, regulation, and damage repair. Crustaceans possess an open circulatory system, where nutrients, oxygen, hormones, and cells are distributed in the hemolymph [1] . Crustaceans lack adaptive immune system and they rely exclusively on their innate immune mechanisms that include both cellular and humoral responses [2] .…”