Structure-function relationships of immunostimulatory polysaccharides: A review.

Immunostimulatory polysaccharides are compounds capable of interacting with the immune system and enhance specific mechanisms of the host response. Glucans, mannans, pectic polysaccharides, arabinogalactans, fucoidans, galactans, hyaluronans, fructans, and xylans are polysaccharides with reported immunostimulatory activity. The structural features that have been related with such activity are the monosaccharide and glycosidic-linkage composition, conformation, molecular weight, functional groups, and branching characteristics. However, the establishment of structure-function relationships is possible only if purified and characterized polysaccharides are used and selective structural modifications performed. Aiming at contributing to the definition of the structure-function relationships necessary to design immunostimulatory polysaccharides with potential for preventive or therapeutical purposes or to be recognized as health-improving ingredients in functional foods, this review introduces basic immunological concepts required to understand the mechanisms that rule the potential claimed immunostimulatory activity of polysaccharides and critically presents a literature survey on the structural features of the polysaccharides and reported immunostimulatory activity.

Autoimmune/inflammatory syndrome (ASIA) induced by biomaterials injection other than silicone medical grade.

BACKGROUND: Systemic autoimmune/granulomatous adverse reactions related to biomaterials other than silicone have rarely been reported. AIM: The aim of this paper is to communicate the cases of autoimmune/inflammatory syndrome induced by adjuvants (ASIA) in a study of Spanish patients suffering from inflammatory disorders related to biomaterial injections other than silicone, principally hyaluronic acid, acrylamides or methacrylate compounds. METHODS: The authors performed a retrospective analysis of the clinical, laboratory, histopathology and follow-up of a cohort of 250 cases of patients suffering from inflammatory/autoimmune disorders related to bioimplant injections. RESULTS: Of these 250 cases, patients with adverse reactions related to silicone injections (n = 65) were excluded. Of the remaining 185, 15 cases (8%) had systemic or distant and multiple complaints that could be categorized as ASIA. In all but four patients, inflammatory features at the implantation site preceded distant or systemic manifestations. Abnormal blood tests were common. Eleven cases (73.3%) with inflammatory localized nodules and panniculitis evolved into a variety of disorders, namely, primary biliary cirrhosis, Sjögren's syndrome, sarcoidosis, human adjuvant disease and inflammatory polyradiculopathy. Four cases presented primarily with systemic autoimmune disorders. CONCLUSIONS: Infrequently, biomaterials other than silicone can provoke local inflammatory adverse reactions that may evolve into systemic autoimmune and/or granulomatous disorders. Whether or not these biomaterials act as an adjuvant, they could be included in the ASIA category.

Hyaluronic acid viscosupplements from avian and non-mammalian sources exhibit biocompatibility profiles with unique, source-specific, antigenic profiles.

The objective of this study was to evaluate and compare the biocompatibility profiles of hyaluronic acid (HA) viscosupplements from avian and non-mammalian sources. Inflammatory and immune reactions were assessed in models of both clinically relevant and stringent immunological exposure conditions. Experiments were conducted to evaluate tissue reactions and immunological responses and assess antibody formation with the capacity to bind directly to and cross-react with the different viscosupplements. Mice were exposed to viscosupplements using the air pouch inflammation model and specific immunization using Freund's complete adjuvant (FCA). Murine pouch membrane tissue reactions revealed generally mild to moderate responses, with cellular infiltration and cytokine profiles of pouch tissue characteristic of predominantly fibroblastic responses rather than marked inflammatory reactions. In vitro testing indicated that pouch injections did not elicit detectable T-cell proliferative responses, while antibody assays revealed that mice immunized with viscosupplements in FCA and subsequently boosted were capable of mounting an antibody response with a range of specificities. High reactivity to avian serum albumin was seen in sera from mice injected with HA from an avian source, while low positive reactivity to the bacterial antigen Staphylococcal Lipotechoic Acid was observed in sera from mice injected with HA from bacterial sources. These specificities did not indicate any propensity to cross-react, suggesting that patients with adverse immune responses to HA from an avian source should be unresponsive to subsequent injection with HA from a non-avian source. Overall, the findings demonstrate that viscosupplements exhibit good biocompatibility profiles in the murine air pouch, but when provoked to elicit immunological reactions exhibit unique antigenic spectra. These findings suggest that an immunologically mediated immune reaction directed against avian proteins should not necessarily be a contraindication for the administration of non-avian viscosupplements.

Hyaluronan as an immune regulator in human diseases.

Accumulation and turnover of extracellular matrix components are the hallmarks of tissue injury. Fragmented hyaluronan stimulates the expression of inflammatory genes by a variety of immune cells at the injury site. Hyaluronan binds to a number of cell surface proteins on various cell types. Hyaluronan fragments signal through both Toll-like receptor (TLR) 4 and TLR2 as well as CD44 to stimulate inflammatory genes in inflammatory cells. Hyaluronan is also present on the cell surface of epithelial cells and provides protection against tissue damage from the environment by interacting with TLR2 and TLR4. Hyaluronan and hyaluronan-binding proteins regulate inflammation, tissue injury, and repair through regulating inflammatory cell recruitment, release of inflammatory cytokines, and cell migration. This review focuses on the role of hyaluronan as an immune regulator in human diseases.

Raised serum chondroitin sulfate epitope level in ovarian epithelial cancer.

OBJECTIVE: To determine the value of serum chondroitin sulfate epitope WF6 and hyaluronan (HA) levels as a biomarker for early detection of ovarian epithelial cancer and other gynecological disorders. METHOD: Serum WF6 CS epitope and HA were measured in 91 patients with ovarian epithelial cancer, 39 patients with non-cancer gynecological disorders and 30 healthy women. Serum chondroitin sulfate (CS) WF6 epitope was determined by a competitive immunoassay with the monoclonal antibodies WF6, which specifically recognizes an epitope in native CS chains. In addition, serum HA concentration was measured by an ELISA-based assay with a biotinylated affinity HA-binding proteins. RESULTS: The serum concentration of CS (WF6) epitope was highly increased in epithelial types of ovarian cancer and at all stages of development (p < 0.005). Serum HA in ovarian cancer patients was significantly higher than normal controls (p < 0.05). CONCLUSION: These results reflect changes in ECM metabolism in progressive ovarian cancer, which cause an increase in serum CS epitopes and HA. Therefore, serum CS epitopes may provide useful biomarkers for cancers and other disorders of the ovary. Measurement of serum HA provided complementary information, which may be useful as a discriminator between benign ovarian disorders and malignant ovarian diseases.

Immunogenicity of liposome-bound hyaluronate in mice. At least two different antigenic sites on hyaluronate are identified by mouse monoclonal antibodies.

Hyaluronate (HA) was previously demonstrated to be immunogenic in rabbits. The immunogenicity of HA in mice was studied. Hyaluronidase-digested streptococcal HA (IA1) covalently linked to liposomes (IA1-liposomes) were produced for immunization. Mice immunized with IA1-liposomes developed measurable serum antibodies to IA1, while mice immunized with IA1 in Freund's adjuvant did not. mAbs produced by two stable hybridomas (10G6 and 5F11) from mice immunized with IA1-liposomes produced IgG antibody reactive with HA in ELISA. 10G6 had a much higher avidity for liposome-bound IA1 than free IA1, while 5F11 did not, suggesting that the mode of presentation of IA1 is important in HA immunogenicity and antigenicity. Both mAbs recognized terminal HA immunodeterminants exposed by hyaluronidase treatment. Sonication had no effect on HA reactivity for either mAb. However, ascorbic acid treatment significantly reduced the antigenicity of HA for mAb 5F11, but not 10G6. Only 10G6 was inhibited by glucuronic acid. Electrostatic forces appear to play a role in the binding site of 5F11, but not 10G6. 5F11 crossreacts with heparan sulfate and phosphorylcholine, while 10G6 did not crossreact with any glycosaminoglycans or phosphorylated compounds tested. These results confirm that HA is immunogenic. They suggest that the mode of presentation of HA is important for the induction of the immune response, and in HA antigenicity. At least two different antigenic sites on HA were demonstrated. 10G6 recognizes a terminal HA antigenic site expressed on IA1-liposomes that contains glucuronic acid in its immunodominant site. 5F11 recognizes an HA antigenic site in which electrostatic forces appear to play a role, is sensitive to ascorbic acid treatment, and is crossreactive with heparan sulfate. The use of mAbs should facilitate immunologic studies of HA.