Soybean agglutinin coated PLA particles entrapping candidate vaccines induces enhanced primary and sustained secondary antibody response from single point immunization (original) (raw)
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Drug Delivery, 2003
Poly(lactide) (PLA) polymer particles entrapping immunoreactive tetanus toxoid (TT) were used for generation of immune response using single point immunization. Immunization with different sizes of polymer particles encapsulating immunoreactive TT elicited anti-TT antibody titers that persisted for more than 5 months. However, antibody response generated by single point immunization of either nanoparticles or microparticles were lower than the conventional two doses of alum adsorbed TT. To overcome this limitation, alum was used with particles that improved anti-TT antibody response. Immunization with nanoparticles along with alum resulted in very high and early immune response: high anti-TT antibody titers were detected as early as 15 days postimmunization. However anti-TT antibody titers declined rapidly with time. Immunization with admixture of microparticles and alum elicited higher antibody titers than the particles alone and the antibody titers were high particularly during the later part of the postimmunization period. Single point immunization with admixture of PLA microparticles and alum resulted in an antibody response very close to that achieved by two injection of alum-adsorbed TT. Physical mixture of both a nano-and microparticles along with alum resulted in sustained anti-TT antibody response from very early days of postimmunization until 150 days. The antibody titers were maintained around 50 µg/ml for more than 5 months. These results indicated that immune response from polymer particles can be further improved by use of additional adjuvant. Furthermore, using various size particles or physical mixture of different size particles along with alum, it is possible to modulate the kinetics of immune response using polymer particles based immunization.
Carbohydrate Biopolymers Enhance Antibody Responses to Mucosally Delivered Vaccine Antigens
Infection and Immunity, 2000
We have evaluated the ability of two carbohydrate biopolymers, chitosan and gellan, to enhance antibody responses to subunit influenza virus vaccines delivered to the respiratory tracts of mice. Groups of mice were vaccinated three times intranasally (i.n.) with 10 μg of purified influenza B/Panama virus surface antigens (PSAs), which consist of hemagglutinin (HA) and neuraminidase (NA), either alone or admixed with chitosan or gellan solutions. Separate groups were vaccinated subcutaneously (s.c.) with PSAs adsorbed to Alhydrogel or chitosan or gellan alone i.n. Serum antibody responses were determined by enzyme-linked immunosorbent assay (ELISA) for influenza virus-specific immunoglobulin G (IgG) and by HA inhibition (HAI) and NA inhibition (NAI) assays. The local respiratory immune response was measured by assaying for influenza virus-specific IgA antibody in nasal secretions and by enumerating nasal and pulmonary lymphocytes secreting IgA, IgG, and IgM anti-influenza virus-speci...
Aim To evaluate the dose-dependent immunogenic properties of poly (lactide-co-glycolide) (PLGA) particles coated with cellobiose as antigen carriers for oral immunization. Methods Two types of PLGA-cellobiose particles (PLGA-cellobiose-1 ~ 0.8 μm and PLGA-cellobiose-2 ~ 1.2 μm) containing non-toxic recombinant subunit B (SbB) of diphtheria toxin fused with enhanced green fluorescent protein were characterized in vitro for their size, shape, antigen loading, and ability to induce phagocytosis. Different doses of antigen, immobilized on the particles (2,5 g, 25 g, 250 g, and 2500 g per 1 kg of body weight), were administered per os 3 times with intervals of 2 weeks to BALB/c female mice. The antigen-specific IgG and IgA antibodies were estimated in serum by ELISA. Results Predominantly after the first immunization, increase in concentration of blood antitoxic antibodies was detected. Antigen dose 250 μg per 1 kg body weight was the most immunogenic for IgG antibodies induction for both types of PLGA-cellobiose particles. Antigen doses 25 μg and 2.5 μg per 1 kg body weight were the most immunogenic for IgA antibodies induction by PLGA-cellobiose 1 and 2 particles, respectively. The second and the third treatment had no significant effect on the immune response or even reduced it, which could be explained by immune tolerance induction by the antigens delivered per os. Conclusion Our results suggest that the correct dose of PLGA-cellobiose particles loaded with antigen could significantly increase the humoral immune response against the introduced antigen already after the first immunization. Thus, PLGA particles can be considered as a potent component of oral vaccines.
International Journal of Pharmaceutics, 2011
A majority of antigens require repeated administration to ensure development of adequate humoral and cell mediated immune response. To minimize the number of administrations required, we investigated the utility of biodegradable polymeric lamellar substrate particles of poly (l-lactide) (PLSP) as adjuvant for filarial antigen preparations. PLSP was prepared and characterized and Brugia malayi adult worm extract (BmA) and its SDS-PAGE resolved 54-68 kDa fraction F6 were adsorbed on to PLSP. Swiss mice received a single injection of PLSP-F6, PLSP-BmA, FCA-F6, FCA-BmA and two doses of the plain antigens. Specific IgG, IgG1, IgG2a, IgG2b and IgE levels in serum, IFN-␥, TNF-␣ and nitric oxide (NO) release from cells of the immunized animals in response to antigen challenge were studied. The average size of PLSP particles was <10 m and its % antigen adsorption efficacy was 60.4, 55.2 and 61.6 for BSA, BmA and F6, respectively. Single injection of PLSP-F6 or PLSP-BmA produced better immune responses compared to one injection of FCA-F6/BmA or two injections of plain F6 or BmA. Moreover, PLSP-F6 produced much better response than PLSP-BmA. These data demonstrate for the first time that PLSP is a superior immunoadjuvant for enhancing the immune response to filarial BmA and F6 molecules and obviates the need for multiple immunization injections.
Microencapsulation of Vaccine Antigens and Adjuvants for Mucosal Targeting
Current Immunology Reviews, 2010
Delivery of vaccine antigens that can trigger potent mucosal immune response is one of the effective strategies to overcome a wide array of infectious diseases. Microencapsulation of vaccine antigens with Poly(lactide-co-glycolic acids) (PLGA), an FDA approved biodegradable polymer, has been investigated for targeted M-cell uptake. While PLGA possesses many attractive properties, a successful PLGA based mucosal-targeted vaccine has yet to be introduced. This review focuses on the physiochemical properties important in the preparation of antigen-loaded PLGA microparticles, properties that influence M-cell specific uptake, and the induction of effective immune responses. In addition, a possible role of microparticle properties in immune adjuvant activity is discussed. A careful consideration of these factors may yet lead to the development of an effective needle-free mucosal vaccine using polymer microparticles.
International journal of pharmaceutics, 2005
Polylactide (PLA) polymer particles entrapping tetanus toxoid (TT) were evaluated in terms of particle size, antigen load, dose and additional adjuvant for achieving high and sustained anti-TT antibody titer from single point intramuscular immunization. Admixture of polymer entrapped TT and alum improved the immune response in comparison to particle-based immunization. High and long lasting antibody titer was achieved upon immunization with 2-8 microm size particles. Microparticles within the size range 50-150 microm elicited very low serum antibody response. Immunization with very small particles (<2 microm) and with intermediate size range particles (10-70 microm) elicited comparable antibody response from single point immunization but lower in comparison to that achieved while immunizing with 2-8 microm size particles. Potentiation of antibody response on immunization of admixture of microparticles and alum was also dependent on particle size. These results indicate the need o...
Journal of The Royal Society Interface, 2012
Polymers as an adjuvant are capable of enhancing the vaccine potential against various infectious diseases and also are being used to study the actual autoimmune responses using self-antigen(s) without involving any major immune deviation. Several natural polysaccharides and their derivatives originating from microbes and plants have been tested for their adjuvant potential. Similarly, numerous synthetic polymers including polyelectrolytes, polyesters, polyanhydrides, non-ionic block copolymers and external stimuli responsive polymers have demonstrated adjuvant capacity using different antigens. Adjuvant potential of these polymers mainly depends on their solubility, molecular weight, degree of branching and the conformation of polymeric backbone. These polymers have the ability not only to activate humoral but also cellular immune responses in the host. The depot effect, which involves slow release of antigen over a long duration of time, using different forms (particulate, solutio...
Journal of Controlled Release, 1996
The importance of in vitro degradation of poly(lactide)/poly(lactide-co-glycolide) (PLA/PLGA) microspheres and of the concomitant in vitro release of a natural and a synthetic antigen for eliciting immune response was studied in mice. A variety of PLAs and PLGAs differing in molecular weight (/~ of 14-130 kDa) and in polymer composition (lactic/glycolic acid ratio of 100:00, 75:25, and 50:50) were examined for their in vitro degradation, which ranged from approximately 4 to 20 weeks. Three specific polymers were then selected for microencapsulation of the two antigens tetanus toxoid (TT) and a weakly immunogenic synthetic branched malaria peptide (P30B2). The in vitro release data showed that antigen delivery correlates fairly well with polymer degradation giving rise to a distinct burst release during the first 24 h and an additional release pulse towards the end of polymer degradation. After single subcutaneous administration in mice, long lasting high antibody titers were obtained with the antigen containing microspheres, as compared to TT adsorbed on alum or to P30B2 in Incomplete Freund's Adjuvant. Moreover, the immune responses induced by microspheres were clearly influenced by the antigen release kinetics, the polymer type and the size of the microspheres. The results demonstrate the immunopotentiating properties of the biodegradable microspheres and their potential to elicit long-lasting immune responses after single administration when tailoring in vitro release characteristics and particle size.