This study investigated the immune response elicited in C3H/HeJ mice after oral, parenteral and nasal immunization with purified flagellin from
Salmonella enterica serovar Enteritidis alone or ...conjugated to starch microparticles as adjuvant or together with the uptake-enhancer recombinant cholera toxin B-subunit (rCTB).
Systemic (IgM–IgG, IgA, IgG2a, IgG2b, IgG1) and local (s-IgA) humoral immune responses in the mice were analyzed using enzyme-linked immunosorbent assays (ELISA). Primed splenocytes were also stimulated in vitro with flagellin and the supernatants analyzed for cytokine production. Finally, immunized mice were challenged orally with live
Salmonella.
A high flagellin-specific IgM–IgG response was seen in all groups, especially in mice immunized nasally with flagellin plus rCTB or subcutaneously, but a strong systemic antibody response was also induced when free antigen was given orally. Intranasal or subcutaneous immunization of mice with flagellin plus rCTB or oral immunization with flagellin plus microparticles resulted in a significantly greater mucosal response (higher s-IgA titers in feces) than seen in the control group (
P<0.05). The mucosal IgA responses were significantly correlated with the serum IgA titers. The subclass profile in serum revealed a mixed Th1/Th2-type response, with a predominance of Th1-type, as indicated by the subclass ratio (IgG1/IgG2a+IgG2b). The splenocytes stimulated in vitro produced interferon (IFN)-γ, at levels, which increased with time. The group immunized with flagellin plus rCTB subcutaneously had a relatively higher IFN-γ response than the other groups. Interleukin (IL)-2 was also produced, especially in mice immunized nasally or subcutaneously with flagellin conjugated to microparticles. However, neither IL-4 nor IL-5 was produced in any of the groups. After oral challenge with live serovar Enteritidis, the groups immunized orally or nasally with free flagellin had significantly lower degree of infection than the control group (
P<0.05).
Starch microparticles as vaccine adjuvant Rydell, Niclas; Stertman, Linda; Sjöholm, Ingvar
Expert opinion on drug delivery,
09/2005, Volume:
2, Issue:
5
Journal Article
Peer reviewed
The demand for new vaccine adjuvants is well documented. New purified antigens from parasites, bacterial or viral pathogens, as well as recombinant subunit antigens and synthetic peptides, are often ...inherently weak immunogens; therefore, they need some kind of adjuvant to help initiate an immune response. In addition, there are very few adjuvants using the potential of the mucosal immune system, which may play an important role in the defence against air- and food-borne infections. Starch is a natural biocompatible and biodegradable polymer that is suitable for the production of various particulate adjuvant formulations, which can induce mucosal as well as systemic immune responses. This review gives an account of the different starch adjuvants used in immunisation studies. In particular, the properties of polyacryl starch microparticles as an oral vaccine adjuvant that induce protective immune responses in mice challenge experiments are summarised. In addition, a diphtheria booster vaccine has been proposed to be used to proving the concept in man and the possibilities to design an efficient vaccine formulation for human use are discussed.
A new vaccine adjuvant for oral administration has been examined in mice. Polyacryl starch microparticles (2–3
μm in diameter) are prepared from a water-in oil-emulsion with stabilising hydrocarbon ...chains. A model antigen, human serum albumin (HSA), which is not binding to the gut epithelium, was covalently coupled to the highly porous starch particles. Upon oral administration, the HSA-microparticles induced a good, diversified immune response without any signs of tolerance development. A strong cellular response can be detected as a delayed-type hypersensitivity reaction. The Th1/Th2 ratio increased with the number of doses and time during the immunisation procedure as indicated by the subclass distribution of the systemic, humoral response. Furthermore, the mucosal response was very strong in the groups that received HSA-microparticles, while the groups receiving soluble HSA did not have any detectable s-IgA in faeces. The specificity was confirmed in an ELISPOT assay. These findings indicate that starch microparticles can be an interesting candidate as an oral vaccine adjuvant. The possible causes of the strong immune responses and the possible role of the dendritic cells in the diversified immune response are discussed.
This paper describes the effects on the development of an immune response by changing the route of administration of a new vaccine adjuvant, starch microparticles with human serum albumin (HSA) as a ...model antigen. The model vaccine was administered to mice by oral, subcutaneous and intramuscular routes in various combinations and both the local secretory immunoglobulin antibody (s-IgA) and systemic humoral and cellular (delayed-type hypersensitivity assay (DTH)) responses were followed. The only immunisation regimens inducing a significant s-IgA response were those incorporating oral booster doses. Oral and subcutaneous immunisations had similar effects on the Th1/Th2 balance, as indicated by the IgG subclass ratios and cytokine analyses. However, significant differences between oral and intramuscular immunisations were seen in the IgG subclass ratios. The Th2 influence was stronger after oral primary immunisation than after intramuscular primary immunisation, while oral boosters elicited a comparatively stronger Th1 response than intramuscular boosters. This result was also supported by the DTH analyses. Subcutaneous immunisation induced a stronger Th2 response than intramuscular immunisation, as indicated by subclass ratio and the IgE response. In conclusion, our results show that the profile of an immune response depends on the route of administration, which should be considered when developing new vaccines or new routes of administration.
Starch microparticles have been shown to be effective as a particulate adjuvant carrier in oral vaccination. In mice, formulations with bacterial antigens have elicited both systemic and mucosal ...immune responses providing protection upon challenge with live bacteria. A vaccine formulation with formaldehyde-treated diphtheria toxin cross-reacting material, CRM197, optimised in mice, was tested in healthy volunteers in a booster design. Specific antibodies as well as toxin-neutralising antibodies in a Vero cell analysis indicated that the vaccine was not effective in man. It is obvious that the longer transit time in the human GI tract and possible unfavourable distribution of Peyer's patches and M-cells necessary for the uptake of the starch particles require a more stable formulation. It is proposed that enteric coating of the particles or particles in a gastro-resistant capsule could be a more efficacious vaccine formulation.
Abstract Uptake of antigens and bacteria over the follicle-associated epithelium (FAE) is increased after chronic psychological stress. We investigated whether stress affects the immune response to ...particle-conjugated antigens taken up via the FAE. Rats were submitted to two 10-day periods of water avoidance stress and orally immunized during these periods. Stressed immunized rats displayed altered cell populations and a Th1-skewed immune response within the lymphoid follicles, together with enhanced delayed-type hypersensitivity. We conclude that chronic stress affects the cell-mediated immune response after oral immunization, which may have implications for the understanding of allergic and autoimmune diseases and development of oral vaccines.
Macromolecules were immobilized by an emulsion polymerization technique in biodegradable microspheres of polyacryldextran, prepared by copolymerizing bisacrylamide with acryldextran. Such particles ...can be characterized by D-T-C expressions, where D denotes the concentration of derivatized dextran, T is the total concentration of acrylic compounds in the monomeric solution, and C denotes the fraction of cross-linker. In microparticles based on dextran T40 with a D-T-C of 11-1-75, the yield of immobilized protein was greater than in polyacrylamide particles. The properties of the immobilized proteins, e.g., Km and Vmax, were retained. The heat stability of the proteins was improved so that 5--10% of carbonic anhydrase still was active after 30 min at 100 degrees. However, the leakage of proteins from the polyacryldextran particles was greater than from polyacrylamide particles.
Oral vaccination offers the advantage of eliciting both a mucosal and a systemic immune response. This study investigated the use of polyacryl starch microparticles as adjuvant for oral vaccination ...against diphtheria. Diphtheria toxin or cross-reacting material (CRM197) were covalently conjugated to the microparticles and fed to mice by oral gavage. Investigation of formaldehyde treatment as a means of either detoxifying (diphtheria toxin) or stabilising (CRM197) these formulations were also made. We show that all our formulations given orally or parenterally to mice induced a strong systemic immune response. Only formulations given orally induced a mucosal IgA-response. Furthermore, our formulations given parenterally or orally induced a strong diphtheria toxin-neutralising antibody response.
Starch microparticles, an effective adjuvant for oral vaccination in mice, are taken up over the follicle-associated epithelium (FAE) in Peyer's patches when human serum albumin is conjugated to the ...particles (HSAmp). When recombinant cholera toxin B subunit (rCTBmp) is conjugated, they are taken up over both the FAE and the villus epithelium. This study investigated the effects of the different targeting on the immune response by using particles with both HSA and rCTB (HSA/rCTBmp). The response induced after oral immunisation with this formulation in mice was compared with that obtained after administration of HSAmp, rCTBmp or both given concomitantly (HSAmp
+
rCTBmp) and after subcutaneous administration. Both the HSA- and rCTB-specific responses were followed quantitatively (as assessed by the anti-IgM
+
IgG level, the s-IgA response and the delayed-type hypersensitivity DTH response), or qualitatively (by the IgG subclass profile). After subcutaneous administration, the rCTB-specific IgM
+
IgG and DTH responses were lower after HSA/rCTBmp than after rCTBmp and the HSA-specific subclass ratio (IgG1/IgG2a
+
IgG2b) was lower with HSAmp
+
rCTBmp (but not with HSA/rCTBmp) compared to HSAmp. However, no quantitative and qualitative differences in the immune response after oral administration were detected when rCTB was added to HSAmp. The results indicate that only the uptake over the Peyer's patches decides the immune responses after oral administration and that the increased targeting to GM1 receptors of the villus epithelium does not affect the immune response. Moreover, the qualitative Th1/Th2-balance is controlled by the inherent properties of the antigens in the microparticles upon subcutaneous administration. Thus, the obtained information is important for designing oral microparticulate vaccines in order to obtain the wanted immune response.
PDF
