The immune response of cephalopods from head to foot

Abstract

Cephalopods are a diverse group of marine molluscs that have proven their worth in a vast array of ways, ranging from their importance within ecological settings and increasing commercial value, to their recent use as model organisms in biological research. However, despite their acknowledged importance, our understanding of basic cephalopod biology does not equate their ecological, societal, and scientific significance. Among these undeveloped research areas, cephalopod immunology stands out because it encompasses a wide variety of scientific fields including many within the biological and chemical sciences, and because of its potential biomedical and commercial relevance. This review aims to address the current knowledge on the topic of cephalopod immunity, focusing on components and functions already established as part of the animals' internal defense mechanisms, as well as identifying gaps that would benefit from future research. More specifically, the present review details both cellular and humoral defenses, and organizes them into sensor, signaling, and effector components. Molluscan, and particularly cephalopod immunology has lagged behind many other areas of study, but thanks to the efforts of many dedicated researchers and the assistance of modern technology, this gap is steadily decreasing. A better understanding of cephalopod immunity will have a positive impact on the health and survival of one of the most intriguing and unique animal groups on the planet, and will certainly influence many other areas of human interest such as ecology, evolution, physiology, symbiosis, and aquaculture.

Haematopoiesis in molluscs: A review of haemocyte development and function in gastropods, cephalopods and bivalves

“…Cephalopods differ from other molluscs in that they have a closed circulatory system that consists of a central heart, two branchial hearts, and a system of blood vessels throughout the tissues [31]. …”

“…The white body is a multi-lobed organ that wraps around the optic bundle [22, 31]. Haematopoietic development in the white body was first described in the common octopus O. vulgaris by Cowden (1972) [98], who identified primary, secondary and tertiary leukoblasts in histological sections.…”

“…Haemocytes in octopus and cuttlefish can phagocytose bacteria, zymosan, and synthetic beads [26, 31, 99]. Cytotoxic activity, characterized by the production of reactive oxygen species and reactive nitrogen species, has been demonstrated in octopus, cuttlefish and squid haemocytes (Reviewed in [31]). Haemocytes of the curled octopus, Eledone cirrhosa , have been implicated in wound healing.…”

“…Other reported pericardial sites of gastropod haemocyte production include the external surface of the ctenidial/pulmonary and renal veins in the pericardial cavity [30]. In cephalopods, haemocytes are thought to originate from the white body, which is a multi-lobed organ that wraps around the optic bundle [22, 31], while in the bivalves, the irregularly folded structure (IFS) of the gills has been proposed as the site of haemocyte formation [21]. In many members of these molluscan groups, a haematopoietic site is yet to be described, and it is possible that more than one primary haematopoietic site exists within each of these groups.…”

Gal/GalNAc specific multiple lectins in marine bivalve Anadara granosa

“…Due to lack of antibody-based immunity, host defense of molluscs and other invertebrates against pathogen infection solely depends on different pattern recognition proteins (PRPs). Different PRPs such as lectins, cytokines, nitric oxide synthases and antimicrobial peptides comprise innate immune systems of molluscs [1,2]. Among them, lectins play a crucial role in innate immunity by recognizing different patterns of carbohydrate exposed on microorganisms and subsequently trigger a series of protective immune responses [3,4].…”