In vitro investigations on the effects of semi-synthetic, sulphated carbohydrates on the immune status of cultured common carp (Cyprinus carpio) leucocytes

Abstract

The rapid emergence of drug resistance, unfavourable immunosuppression and mounting evidence to suggest the deleterious accumulation of drug breakdown residues within animal tissues has driven a strong desire to move away from these current methods of disease control. Some natural products such as β-glucan, which are extracted from, for example, plants and fungi, are able to modulate the immune system and increase protection against diseases. However, these products are heterogeneous and their effects can be variable thus limiting their applicability and reliability. Carbohydrates were modified via chemical sulphation and these semi-synthetic, sulphated carbohydrates analysed for their immunological activity utilising carp pronephric cells and a carp leucocyte cell line (CLC). A sulphated β(1,4)-glucan, methyl hydroxyethyl cellulose sulphate (MHCS), demonstrated a stimulatory effect on fish immune cells. MHCS induced a range of bioactive effects in carp leucocyte cells whilst not affecting cell viability when cells were exposed for 24 h at concentrations of 1-150 μgml. MHCS stimulated the innate immune system where a significant increase in respiratory burst activity was observed at concentrations 25-250 μgml in comparison to control (sterile water), cellulose ether, MacroGard and zymosan. Also, under in mock bacterial and viral infection conditions i.e. Lipopolysaccharide (LPS) and polyinosinic:polycytidylic acid (Poly(I:C)), MHCS enhanced the immune responses of pronephric cells by stimulating the respiratory burst activity at concentrations 50 and 150 μgml. MHCS also enhanced the expression of cytokines including interleukin 1 beta (IL1β), tumor necrosis factor alpha 1 and 2 (TNFα 1,2), interferons alpha 2 (IFN α2) and inducible nitric oxide synthase (iNOS) in carp pronephric cells. It is proposed that this new semi-synthetic carbohydrate is a potential candidate for the development of a new generation of immunostimulants and adjuvants for use in vaccination strategies in aquaculture.

Effect of β‐1/3,1/6‐glucan upon immune responses and bacteria in the gut of healthy common carp (Cyprinus carpio)

“…Since il‐1β serves as an inflammatory cytokine, it is possible that it would be upregulated during infection, however, the continued correlation under disease free conditions could indicate a role in maintaining the size of the gut bacteria population. Unlike several previously published in vitro trials in carp (Biswas et al ., ; Pietretti et al ., ; Kareem et al ., ), here β‐glucan significantly reduced overall expression of il‐1β in the gut. In contrast to in vitro trials, the effect of β‐glucan upon inflammatory cytokine gene expression in vivo has produced inconsistent results (Djordjevic et al ., ; Falco et al ., ; Medina‐Gali et al ., ).…”

Recent Advances in Artificially Sulfated Polysaccharides for Applications in Cell Growth and Differentiation, Drug Delivery, and Tissue Engineering

“…Cellulose, as the most abundant polysaccharide in nature, has been used as a starting material for the synthesis of the GAG‐analogue CS, which is often stored in its sodium salt form (NaCS) . CS, derived from cellulose through different sulfating routes, has favorable biological properties, such as excellent water solubility, biodegradability, nontoxicity, and biocompatibility . There are generally six methods to synthesize CS by using diverse sulfating agents (Table ) .…”

“…CS, derived from cellulose through different sulfating routes, has favorable biological properties, such as excellent water solubility, biodegradability, nontoxicity, and biocompatibility . There are generally six methods to synthesize CS by using diverse sulfating agents (Table ) . The chemical structure of CS, the distribution and the position of sulfate groups, and the physicochemical properties can be determined by combining various methods, such as FTIR, FT Raman, and NMR spectroscopy; elemental, thermogravimetric, and differential thermal analyses; and wide‐angle X‐ray diffraction .…”

“…There are generally six methods to synthesize CS by using diverse sulfating agents (Table ) . The chemical structure of CS, the distribution and the position of sulfate groups, and the physicochemical properties can be determined by combining various methods, such as FTIR, FT Raman, and NMR spectroscopy; elemental, thermogravimetric, and differential thermal analyses; and wide‐angle X‐ray diffraction . In addition, the molecular weight of CS can be measured by means of low‐angle laser light scattering and gel permeation chromatography (GPC) .…”

“…The physical, chemical, and biological properties of CS, for example, water solubility, reactive activity, and biological activities, are mainly dependent on the DS, charges, molecular weight, and distribution of substituents along the chain . As a water‐soluble derivative, CS exhibited diverse biological effects, such as anticoagulation, antiviral activity, and support of cell growth and differentiation either in soluble form or as one component of a drug carrier or tissue engineering scaffolds . We subsequently herein mainly summarize their effects on cells and their use for making carriers for drug release and implant materials, because other applications have already been covered in many other reviews …”