Extracellular Matrix from Porcine Small Intestinal Submucosa (SIS) as Immune Adjuvants

Abstract

Porcine small intestinal submucosa (SIS) of Cook Biotech is licensed and widely used for tissue remodeling in humans. SIS was shown to be highly effective as an adjuvant in model studies with prostate and ovarian cancer vaccines. However, SIS adjuvanticity relative to alum, another important human-licensed adjuvant, has not yet been delineated in terms of activation of innate immunity via inflammasomes and boosting of antibody responses to soluble proteins and hapten-protein conjugates. We used ovalbumin, and a hapten-protein conjugate, phthalate-keyhole limpet hemocyanin. The evaluation of SIS was conducted in BALB/c and C57BL/6 mice using both intraperitoneal and subcutaneous routes. Inflammatory responses were studied by microarray profiling of chemokines and cytokines and by qPCR of inflammasomes-related genes. Results showed that SIS affected cytokine and chemokines microenvironments such as up-regulation of IL-4 and CD30-ligand and activation of chemotactic factors LIX and KC (neutrophil chemotactic factors), MCP-1 (monocytes chemotactic factors), MIP 1-α (macrophage chemotactic factor) and lymphotactin, as well as, growth factors like M-CSF. SIS also promoted gene expression of Nod-like receptors (NLR) and associated downstream effectors. However, in contrast to alum, SIS had no effects on pro-inflammatory cytokines (IL-6, IL-1β, TNF-α) or NLRP3, but it appeared to promote both Th1 and Th2 responses under different conditions. Lastly, it was as effective as alum in engendering a lasting and specific antibody response, primarily of IgG1 type.

Effects of Small Intestinal Submucosa (SIS) on the Murine Innate Immune Microenvironment Induced by Heat-Killed Staphylococcus aureus

“…It has shown promise as a cancer vaccine adjuvant against human prostate cancer by evoking effective cell-mediated immunity [17]. In an earlier study, we have reported the efficiency of SIS in augmenting the immunogenic potential of soluble protein antigens like ovalbumin and keyhole-limpet hemocyanin [18]. We also described that SIS exhibits adjuvanticity without inducing any adverse pathologic inflammatory response even in autoimmune prone NZB/WF1 mice [19].…”

“…In this respect, SIS is better than some commercial adjuvants that often induce inflammatory tissue damage at sites of injection. The particulate nature of SIS may also promote phagocytosis, antigen uptake and retention by antigen presenting cells (APCs) [18].…”

“…Analysis of the Th1/Th2 balance induced by SIS has shown a robust IL-4 (Th2) expression with a characteristic IgG1 antibody response [18], [21]. The Th2 response, characterized by the expression of cytokines like IL-4, IL-10, IL-13, favors transplant acceptance.…”

Engaging adaptive immunity with biomaterials

“…For example, when SIS was formulated into particles and combined with non-self antigens or hapten-protein conjugates, it increased the magnitude of the antibody response (primarily IgG1) against the antigens or haptens, again without promoting significant inflammation. 78 Little is known about which proteins are immunodominant, what the affinity of the antibody responses are, or how diverse of an antibody and T cell repertoire is generated, as titers have been measured against multi-component extracts of the implanted material. Conclusively identifying the epitopes and/or the main immunomodulating components that positively and negatively influence these processes is challenging.…”

Efficacy of phytol-derived diterpenoid immunoadjuvants over alum in shaping the murine host's immune response to Staphylococcus aureus

“…Serum antibody levels were measured and isotyping of antibodies performed by ELISA as described previously [26]. For all experiments plates were coated with 50 l of 10 g/ml sonicated S. aureus.…”