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 Table of Contents  
ORIGINAL ARTICLE
Year : 2015  |  Volume : 4  |  Issue : 3  |  Page : 333-338

Enhancing the immunomodulatory effects of the Toll-like receptors 3 agonist poly(I:C) by conjugation with polymers


1 Department of Zoology, Faculty of Science, Immunology and Biotechnology Unit, Tanta University; Immunology and Biothechnology Division, Center of Excellence in Cancer Research, Tanta University, Tanta, Egypt
2 Department of Zoology, Faculty of Science, Immunology and Biotechnology Unit, Tanta University, Tanta, Egypt
3 Department of Laser, Laser Institute, Cairo University, Giza, Egypt

Date of Web Publication13-May-2015

Correspondence Address:
Mohamed Labib Salem
Department of Zoology, Faculty of Science, Immunology and Biotechnology Unit, Center of Excellence in Cancer Research, Tanta University, Tanta
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/2278-0513.154811

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  Abstract 

Background : Poly(I:C) is a Toll-like receptors 3 agonist, which induces potent innate immune responses, and as a consequence adaptive immunity. However, the rapid degradation of poly(I:C) influences its half-life and its adjuvant effects in preclinical and clinical uses. Aims : We aimed in this study to conjugate poly(I:C) with polyethylene glycol/poly D, L-actide-co-glycolide (PLGA/PEG) polymers as an approach for better delivery and immunomodulatory effects. Materials and Methods : Female CD1 mice were treated once with PEG/PLGA, poly(I:C)/PLGA/PEG (50 μg), poly(I:C)/ PLGA/PEG (10 μg) or PEG via intraperitoneal injection and mice were sacrificed 1 day later for complete blood count analysis and analysis of the immune cells by flow cytometry. Results : Treatment with PEG/PLGA, poly(I:C)/PLGA/PEG (50 μg), poly(I:C)/PLGA/PEG (10 μg) or PEG administration resulted in significant (P = 0.0197) increases (1.89, 1.76, 1.69, and 1.42-fold, respectively) in the absolute number of neutrophils as compared to naïve mice. Conclusion : Conjugation of poly(I:C) with polymers does not hamper its immunomodulatory effects, instead it enhances its effects on increasing the number of immune cells opening an avenue for further studies on the beneficial effects of this conjugate.

Keywords: Blood, cancer, immune cells, poly(I:C), polymer


How to cite this article:
Salem ML, Tosson EM, Mohamed MB, Aboualkheir LM. Enhancing the immunomodulatory effects of the Toll-like receptors 3 agonist poly(I:C) by conjugation with polymers. Clin Cancer Investig J 2015;4:333-8

How to cite this URL:
Salem ML, Tosson EM, Mohamed MB, Aboualkheir LM. Enhancing the immunomodulatory effects of the Toll-like receptors 3 agonist poly(I:C) by conjugation with polymers. Clin Cancer Investig J [serial online] 2015 [cited 2019 Oct 14];4:333-8. Available from: http://www.ccij-online.org/text.asp?2015/4/3/333/154811


  Introduction Top


Toll-like receptors (TLRs) are a group of receptors that are expressed at high levels by innate immune cells and low levels by adaptive immune cells. TLR3 binds to a number of microbial products called TLR ligands (TLRLs) such as LPS (TLR4 L), viral single and double-stranded ribonucleic acid (TLR7/8 L and TLR3 L, respectively), bacterial and viral deoxyribonucleic acid (TLR9 L). [1] TLR engagement stimulates the innate immune cells, such as dendritic cells (DCs), macrophages, and natural killer (NK) cells, and as a consequence results in activation of T cells. As such, TLRLs have been utilized as adjuvants to potentiate antitumor immune responses in preclinical studies. [2] Of interest, following the Immunotherapy Agent Workshop held recently at the National Cancer Institute, both polyinosinic-polycytidylic acid (poly(I:C)) and CpG were included on a ranked list of 20, out of 124, agents with high potential for use in treating cancer (http://web.ncifcrf.gov/research/brb/workshops.asp). Poly(I:C), a synthetic double-stranded RNA, has been identified as a synthetic TLR3 agonist. [3] We and others have reported that poly(I:C) is a potent inducer of DC and NK cell activation and function due to the rapid release of inflammatory cytokines, including interferon-α, resulting in robust expansion, activation, survival of antigen-specific T cell responses and as a consequence anti-tumor effects against advanced melanoma treatment. [4],[5],[6],[7],[8],'9] One limitation of poly(I:C), however, is its rapid degradation by the endogenous endonucleases and as a consequence shortening its half-life and it's biological efficacy. [10],[11] Two clinical forms of poly(I:C) have been developed to enhance delivery of poly(I:C) named polyICLC (Hiltonol® ) and Ampligen® by chemical stabilization [12],[13] and nucleotide mismatching, [14] respectively. Developing further strategies that can avoid rapid degradation of poly(I:C) is of a great significance to enhance its biological effect. [15]

One of the most biocompatible, popular polymers is polyethylene glycol (PEG) due to its excellent profile. [16] It can reduce the cytotoxicity of the polymer/DNA complex. PEGylation increases the circulation time of nanoparticles and enhances their ability to accumulate in target organs and enhanced permeability and retention effect. [17] Also, conjugation of polyion complex micelles with PEG/poly (L-lysine) (pLL) polymer showed the highest transfection efficiency to human hepatoma HepG2 cells at a 4:1 charge ratio which was higher than that of pLL of the same molecular weight. [18] When microparticle systems contains poly D, L-actide-co-glycolide (PLGA) polymer is preferable, as PLGA has acidic degradation products providing a supportive privilege to proteins and nucleic acids degradation within the acidic microclimate inside PLGA particles. [19] In addition, when PLGA is combined with PEG polymer it results in a potent activity in delivery of cisplatin and targeting the prostate cancer cells in vitro using functionalized aptamer. [20] Furthermore, the conjugation of the two efficient polymers PLGA, PEG has been proved to be effective in combination with Ps-341 at CF mice which enhanced pro-inflammatory response in CF lungs disease. [21] Taken together, these studies indicate that modification of biological response by certain polymers can enhance their biological effects. The aim of this study was to increase the immunomodulatory effects of poly(I:C) via its conjugation to PLGA and PEG polymers.


  Materials and methods Top


Mice

Female Swiss Albino (CD1) mice 10-week old and 20-25 g (n = 6 per group) were purchased from the National Research Center, Cairo, Egypt. All animals were housed at Animal Facility Unit, Zoology Department, Faculty of Science, Tanta University under the guidelines of the Ethical Committee of this University.

Reagents

Poly(I:C) was purchased from Sigma Chem. Co., (St. Louis, Mo., USA) and prepared under aseptic conditions and dissolved in saline (0.9%) and diluted to the required dose for intraperitoneal (i.p.) injection. Poly(I:C)/PLGA/PEG was prepared at Nanothech Inc., Cairo, Egypt. Anti CD16/CD32, anti-CD11b, anti-Ly6G (Gr1) were purchased from Pharmingen (San Diego, CA, USA).

Preparation of poly (I:C)/poly D, L-actide-co-glycolide/polyethylene glycol

About 13.3 mg of PLGA copolymer, lactide: Glycolide (50:50), mol wt 30,000-60,000, (Sigma-Aldrich Co.), was dissolved in 2 mL chloroform (Elmaadi for Medical Service, Cairo, Egypt). About 250 mg of (PEG) polymer (BioUltra, mol wt 20,000) was dissolved in 5 mL distilled water on the magnetic plate. Then, poly(I:C) (500 μg/100 μl) was added after stirring for 2 min. PLGA solution was added to PEG/poly(I:C) solution drop by drop for 5 h by oil/water emulsion/solvent evaporation method. For preparation of nanoparticles, shaking sonicator was applied into the resultant solution for 1 h to prepare two different concentration poly(I:C)/PLGA/PEG (50 μg), poly(I:C)/PLGA/PEG (10 μg). For preparation of PLGA-PEG, about 13.3 mg of PLGA copolymer, lactide: Glycolide (50:50), mol wt 30,000-60,000 was dissolved in 2 mL chloroform added to 250 mg of PEG polymer (BioUltra, mol wt 20,000) previously dissolved in 5 mL distilled water. PLGA solution was added to PEG solution drop by drop for 5 h by oil/water emulsion/solvent evaporation method. For the preparation of nanoparticles, shaking sonicator was applied into the resultant solution for 1 h. For preparation of PEG (2.5 mg), about 250 mg of PEG polymer (BioUltra 20,000) was dissolved in 5 mL distilled water, shaking sonicator for the preparation of nanoparticles was applied into the resultant solution for 1 h.

Treatment protocol

Naïve mice were treated once with i.p. injection of PBS, treated mice were injected with poly(I:C) (100 μg), poly(I:C)/PLGA/PEG (50 μg/13.3 μg/2.5 mg), poly(I:C)/PLGA/PEG (10 μg/2.66 μg/0.5 mg), PEG/PLGA (2.5 mg/13.3 μg) or PEG (2.5 mg) and dissected 1 day later.

Complete blood count analysis

At the indicated time points, mice were bled from the orbital sinus to harvest peripheral blood and then sacrificed to harvest liver and spleen. The total number of leukocytes in peripheral blood was enumerated using an automated instrument for complete blood count (CBC) (VetScan HM2 Hematology System, Abaxis® , Union City, CA, USA).

Flow cytometry

About 1 × 10 6 cells were treated with anti-CD16/CD32 for 5 min on ice. Cells were then stained with the indicated fluorochrome conjugated mAbs, including anti-CD11b, anti-Ly6G (Gr1), and incubated for 30 min on ice in the dark. The cells were washed twice and resuspended in 0.3 mL of 0.5% BSA, 0.02% sodium azide solution. Cells were acquired on a FACS Calibur (BD Bio-sciences, San Jose, CA, USA) and analyzed using FlowJo Software (BD Biosciences, San Jose, CA, USA). The absolute number of stained cells = percentage of stained cells × WBCs from CBC/100.

Statistics

Numerical data obtained from each experiment were expressed as mean ± SD and statistical differences between experimental and control groups were assessed using the Student's t-test. P < 0.05 were considered statistically significant.


  Results Top


Effects of treatments on total and differential numbers in peripheral blood mononuclear cells

Administration of poly(I:C) at 100 μg, PEG, poly(I:C)/PLGA/PEG at 10 or at 50 μg had no effect on the total number of white blood cells as compared to naïve mice. However, the administration of PEG/PLGA induced significant (P = 0.0434) increase (1.36-fold) in the total number of white blood cells as compared to the naïve mice [Figure 1].
Figure 1: The total number of peripheral blood mononuclear cells after single administration of (polyethylene glycol/poly D,L-actide-co-glycolide [PEG/PLGA]), poly(I:C) (100 μg), poly(I:C)/PLGA/PEG (50 μg), poly(I:C)/PLGA/PEG (10 μg) or PEG into naïve mice. Mice were bled 24 h after injection

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Administration of poly(I:C) at 100 μg, poly(I:C)/PLGA/PEG at 10 μg, at 50 μg, PEG or PEG/PLGA, induced significant (P = 0.0001) increase (2.87, 5.6, 2.68, 4.75 and 2.87-fold, respectively) in the relative numbers of neutrophils [Figure 2]b, induced significant (P = 0.0001) increase (2.5, 2, 1.75, 1.25, and 1.5-fold, respectively) in the relative number of monocytes [Figure 2]d as compared to naïve mice.
Figure 2: Naïve mice were administered single injection with (polyethylene glycol/poly D,L-actide-co-glycolide [PEG/PLGA]), poly(I:C) (100 μg), poly(I:C)/PLGA/PEG (50 μg), poly(I:C)/PLGA/PEG (10 μg) or PEG. Mice were bled 24 h after injection. (a) The absolute number of neutrophils, (b) the percentage of neutrophils, (c) the absolute number of monocytes and (d) the percentage of monocytes

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Administration of poly(I:C) at 100 μg induced significant (P = 0.0197) decrease (0.8-fold) in the absolute number of neutrophils, induced significant (P = 0.0129) decrease (0.78-fold) in the absolute number of monocytes as compared to naïve mice. However, administration of PEG, PEG/PLGA, poly(I:C)/PLGA/PEG at 50 μg or at 10 μg induced significant (P = 0.0197) increases (1.89, 1.76, 1.69 and 1.42-fold, respectively) in the absolute number of neutrophils [Figure 2]a, induced significant (P = 0.0129) increases (2.18, 1.82, 1.83, and 1.32-fold, respectively) in the absolute number of monocytes [Figure 2]c as compared to naïve mice.

Administration of poly(I:C) at 100 μg, PEG/PLGA or poly(I:C)/PLGA/PEG at 10 μg had no significant effect on the relative number of lymphocytes as compared to naïve mice [Figure 3]b. In contrast, administration of PEG or poly(I:C)/PLGA/PEG at 50 μg induced significant (P = 0.0001) decreases (0.81, 0.79-fold, respectively) in the relative number of lymphocyte as compared to naïve mice. Administration of poly(I:C) at 100 μg, PEG, poly(I:C)/PLGA/PEG at 10 μg or at 50 μg had no significant effect on the absolute number of lymphocyte as compared to naïve mice. However, administration of PEG/PLGA induced significant (P = 0.0242) increase (1.27-fold) in the absolute number of lymphocytes as compared to naïve mice [Figure 3]a.
Figure 3: Naïve mice were administered single injection with (polyethylene glycol/poly D,L-actide-co-glycolide [PEG/PLGA]), poly(I:C) (100 ìg), poly(I:C)/PLGA/PEG (50 ìg), poly(I:C)/PLGA/PEG (10 ìg) or PEG. Mice were bled 24 h after injection. (a) The absolute number of lymphocytes and (b) the parentage of lymphocytes

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Effects of treatments on myeloid cell populations in peripheral blood mononuclear cells

Administration of poly(I:C) at 100 μg, PEG/PLGA, PEG, poly(I:C)/PLGA/PEG at 10 μg or at 50 μg had no significant effect on the relative number of CD11b + Ly6G cells as compared to naïve mice [Figure 4] and [Figure 5]b). Administration of poly(I:C) at 100 μg induced significant (P = 0.0045) decrease (0.66-fold) in the absolute number of CD11b + Ly6G cells as compared to the naïve group. However, administration of PEG/PLGA, PEG, poly(I: C)/PLGA/PEG at 10 μg or at 50 μg had no significant effect on the absolute number of CD11b + Ly6G cells as compared to naïve mice [Figure 4] and [Figure 5]a.
Figure 4: Naïve mice were administered single injection with (polyethylene glycol/ poly D,L-actide-co-glycolide [PEG/PLGA]), poly(I:C) (100 μg), poly(I:C)/PLGA/ PEG (50 μg), poly(I:C)/PLGA/PEG (10 μg) or PEG. Mice were bled 24 h after injection. The gating of myeloid cell populations expressing CD11b and/or Ly6G molecules were estimated using flow cytometry after staining with anti-CD11b and anti-Ly6G monoclonal antibodies

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Figure 5: Naïve mice were administered single injection with (polyethylene glycol/poly D,L-actide-co-glycolide [PEG/PLGA]), poly(I:C) (100 μg), poly(I:C)/PLGA/PEG (50 μg), poly(I:C)/PLGA/PEG (10 μg) or PEG. Mice were bled 24 h after injection. (a) The absolute number of CD11b+Ly6G− cells, (b) the percentage of CD11b+Ly6G− cells, (c) the absolute number of CD11b+Ly6G+cells and (d) the percentage of CD11b+Ly6G+cells. The gating of myeloid cell populations expressing CD11b and/or Ly6G molecules were estimated using flow cytometry after staining with anti-CD11b and anti-Ly6G monoclonal antibodies

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Administration of poly (I:C) at 100 μg, PEG/PLGA, poly(I:C)/PLGA/PEG at 10 μg or at 50 μg had no significant effect on the relative number of CD11b + Ly6G + cells as compared to naïve mice. However, administration of PEG induced significant (P = 0.0049) increase (1.66-fold) in the relative number of CD11b + Ly6G + cells as compared to naïve mice [Figure 4] and [Figure 5]d.

Administration of poly(I:C) at 100 μg, poly(I:C)/PLGA/PEG at 50 μg or at 10 μg had no significant effect in the absolute number of CD11b + Ly6G + cells as compared to naïve mice. However, administration of PEG or PEG/PLGA induced significant (P = 0.0001) increases (1.91, 1.79-fold, respectively) in the absolute number of CD11b + Ly6G + cells as compared to naïve mice [Figure 4] and [Figure 5]c.


  Discussion Top


Poly(I:C) is known to be rapidly degraded by endogenous endonucleases resulting in shortening its half-life, and as a consequence its biological efficacy. [10],[11] As such, improving poly(I:C) prosperities by its conjugation with PLGA/PEG copolymers may solve this limitation. We determined that administration of conjugated poly(I:C) resulted in activation of both neutrophil and monocyte indicating the capability of these polymers to enhance their adjuvant efficacy. Of interest, this effect of conjugated poly(I:C) was dose-dependent, indicating the importance of the quantity of the administered poly(I:C). Previous studies showed that poly(I:C) promotes cross-presentation via expressing specific antigens on DCs, enhancing T lymphocyte response and providing antiviral protection. [22] In the present study, poly(I:C) at 100 μg administration induced decreases in the absolute number of neutrophils and monocytes in the blood. The phenotypic analysis of peripheral blood mononuclear cells verified these results as indicated by the decreases in the number of CD11b + Ly6G (monocytes). In line with this decreased cell population in blood, we found that poly(I:C) induced alteration in trafficking of these cell population from blood to other organs such as liver, spleen (unpublished data) as suggested by attrition of CD11b + Ly6G + in the blood after 4 h of poly(I:C) administration. Further studies, however, are needed to confirm this observation.

As compared to free poly(I:C), poly(I:C)/PLGA/PEG conjugate induced increase in the number of neutrophils and monocytes in the blood. Taken together the biological effect of free and conjugated poly(I:C), it can be suggested that the polymers in this conjugate are biologically active. Further, administration of PEG induced increased in the total number of white blood cells, number of neutrophils and monocytes in the blood as well as the phenotypic analysis of CD11b + Ly6G + (neutrophils). The biological activities of poly(I:C)/PLGA/PEG could be explained by prolonged blood circulating polymeric vehicles, as the conjugation of drug with diblock hydrophobic PEGylated polymer will result in polymeric vehicle with hydrophobic core with entrapped drug and surrounded with hydrophilic PEG shell will lead to more stability for the particle and prolonged existence within the circulation. [23]

Although, we did not test the biological activity of PLGA alone previous studies have already described the biological activity of this polymer per se Indeed, PLGA proved to be effective microparticle-based vaccine delivery system. [24] Similar to the enhancing effect of PEG/PLGA on the biological effect of poly(I:C) on the innate immune cells, conjugation of poly(I:C) with calcium phosphate nanoparticles has been found to induce DCs and T cell activation. [25] Given that, poly(I:C) proved to improve the immunostimulatory potential of cetuximab against several cancer cell [26] and the conjugation of TLR4 and cancer associated antigen to PLGA resulted in CD8 + T cell induction mediating anti-tumor immunity. [27] It can be suggested that conjugation of poly(I:C) with anti-cancer drugs into PLGA/PEG polymers will lead to robust immunostimulatory effects and anti-cancer effects.

In conclusion, conjugation of poly(I:C) with certain polymers such as PEG and PLGA can enhance its biological activity in immune response in particular innate immune response. These results might be a significant implication in the preclinical application of poly(I:C). However, further studies are needed to evaluate the anti-cancer attribute of this conjugate.

 
  References Top

1.
Iwasaki A, Medzhitov R. Toll-like receptor control of the adaptive immune responses. Nat Immunol 2004;5:987-95.  Back to cited text no. 1
    
2.
Okamoto M, Sato M. Toll-like receptor signaling in anti-cancer immunity. J Med Invest 2003;50:9-24.  Back to cited text no. 2
    
3.
Alexopoulou L, Holt AC, Medzhitov R, Flavell RA. Recognition of double-stranded RNA and activation of NF-kappaB by Toll-like receptor 3. Nature 2001;413:732-8.  Back to cited text no. 3
    
4.
Salem ML. Triggering of toll-like receptor signaling pathways in T cells contributes to the anti-tumor efficacy of T cell responses. Immunol Lett 2011;137:9-14.  Back to cited text no. 4
    
5.
Salem ML, Diaz-Montero CM, El-Naggar SA, Chen Y, Moussa O, Cole DJ. The TLR3 agonist poly (I: C) targets CD8 T cells and augments their antigen-specific responses upon their adoptive transfer into naïve recipient mice. Vaccine 2009;27:549-57.  Back to cited text no. 5
    
6.
Salem ML, El-Demellawy M, El-Azm AR. The potential use of Toll-like receptor agonists to restore the dysfunctional immunity induced by hepatitis C virus. Cell Immunol 2010;262:96-104.  Back to cited text no. 6
    
7.
Salem ML, El-Naggar SA, Kadima A, Gillanders WE, Cole DJ. The adjuvant effects of the toll-like receptor 3 ligand polyinosinic-cytidylic acid poly (I: C) on antigen-specific CD8 + T cell responses are partially dependent on NK cells with the induction of a beneficial cytokine milieu. Vaccine 2006;24:5119-32.  Back to cited text no. 7
    
8.
Salem ML, Kadima AN, Cole DJ, Gillanders WE. Defining the antigen-specific T-cell response to vaccination and poly (I: C)/TLR3 signaling: Evidence of enhanced primary and memory CD8 T-cell responses and antitumor immunity. J Immunother 2005;28:220-8.  Back to cited text no. 8
    
9.
Salem ML, Kadima AN, El-Naggar SA, Rubinstein MP, Chen Y, Gillanders WE, et al. Defining the ability of cyclophosphamide preconditioning to enhance the antigen-specific CD8 + T-cell response to peptide vaccination: Creation of a beneficial host microenvironment involving type I IFNs and myeloid cells. J Immunother 2007;30:40-53.  Back to cited text no. 9
    
10.
de Clercq E. Degradation of poly (inosinic acid) - poly (cytidylic acid) [(I) n - (C) n] by human plasma. Eur J Biochem 1979;93:165-72.  Back to cited text no. 10
[PUBMED]    
11.
Liu Y, Kimura K, Yanai R, Chikama T, Nishida T. Cytokine, chemokine, and adhesion molecule expression mediated by MAPKs in human corneal fibroblasts exposed to poly (I: C). Invest Ophthalmol Vis Sci 2008;49:3336-44.  Back to cited text no. 11
    
12.
Bangham AD. Lipid bilayers and biomembranes. Annu Rev Biochem 1972;41:753-76.  Back to cited text no. 12
[PUBMED]    
13.
Salazar AM, Levy HB, Ondra S, Kende M, Scherokman B, Brown D, et al. Long-term treatment of malignant gliomas with intramuscularly administered polyinosinic-polycytidylic acid stabilized with polylysine and carboxymethylcellulose: An open pilot study. Neurosurgery 1996;38:1096-103.  Back to cited text no. 13
    
14.
Trumpfheller C, Longhi MP, Caskey M, Idoyaga J, Bozzacco L, Keler T, et al. Dendritic cell-targeted protein vaccines: A novel approach to induce T-cell immunity. J Intern Med 2012;271:183-92.  Back to cited text no. 14
    
15.
Morahan PS, Munson AE, Regelson W, Commerford SL, Hamilton LD. Antiviral activity and side effects of polyriboinosinic-cytidylic acid complexes as affected by molecular size. Proc Natl Acad Sci U S A 1972;69:842-6.  Back to cited text no. 15
[PUBMED]    
16.
Harding JA, Engbers CM, Newman MS, Goldstein NI, Zalipsky S. Immunogenicity and pharmacokinetic attributes of poly (ethylene glycol)-grafted immunoliposomes. Biochim Biophys Acta 1997;1327:181-92.  Back to cited text no. 16
    
17.
Fang J, Sawa T, Maeda H. Factors and mechanism of "EPR" effect and the enhanced antitumor effects of macromolecular drugs including SMANCS. Adv Exp Med Biol 2003;519:29-49.  Back to cited text no. 17
    
18.
Kwoh DY, Coffin CC, Lollo CP, Jovenal J, Banaszczyk MG, Mullen P, et al. Stabilization of poly-L-lysine/DNA polyplexes for in vivo gene delivery to the liver. Biochim Biophys Acta 1999;1444:171-90.  Back to cited text no. 18
    
19.
Tamber H, Johansen P, Merkle HP, Gander B. Formulation aspects of biodegradable polymeric microspheres for antigen delivery. Adv Drug Deliv Rev 2005;57:357-76.  Back to cited text no. 19
    
20.
Dhar S, Gu FX, Langer R, Farokhzad OC, Lippard SJ. Targeted delivery of cisplatin to prostate cancer cells by aptamer functionalized Pt (IV) prodrug-PLGA-PEG nanoparticles. Proc Natl Acad Sci U S A 2008;105:17356-61.  Back to cited text no. 20
    
21.
Vij N, Min T, Marasigan R, Belcher CN, Mazur S, Ding H, et al. Development of PEGylated PLGA nanoparticle for controlled and sustained drug delivery in cystic fibrosis. J Nanobiotechnology 2010;8:22.  Back to cited text no. 21
    
22.
Jelinek I, Leonard JN, Price GE, Brown KN, Meyer-Manlapat A, Goldsmith PK, et al. TLR3-specific double-stranded RNA oligonucleotide adjuvants induce dendritic cell cross-presentation, CTL responses, and antiviral protection. J Immunol 2011;186:2422-9.  Back to cited text no. 22
    
23.
Mora-Huertas CE, Fessi H, Elaissari A. Polymer-based nanocapsules for drug delivery. Int J Pharm 2010;385:113-42.  Back to cited text no. 23
    
24.
Bramwell VW, Eyles JE, Oya Alpar H. Particulate delivery systems for biodefense subunit vaccines. Adv Drug Deliv Rev 2005;57:1247-65.  Back to cited text no. 24
    
25.
Sokolova V, Knuschke T, Kovtun A, Buer J, Epple M, Westendorf AM. The use of calcium phosphate nanoparticles encapsulating Toll-like receptor ligands and the antigen hemagglutinin to induce dendritic cell maturation and T cell activation. Biomaterials 2010;31:5627-33.  Back to cited text no. 25
    
26.
Ming Lim C, Stephenson R, Salazar AM, Ferris RL. TLR3 agonists improve the immunostimulatory potential of cetuximab against EGFR head and neck cancer cells. Oncoimmunology 2013;2:e24677.  Back to cited text no. 26
    
27.
Hamdy S, Molavi O, Ma Z, Haddadi A, Alshamsan A, Gobti Z, et al. Co-delivery of cancer-associated antigen and Toll-like receptor 4 ligand in PLGA nanoparticles induces potent CD8 T cell-mediated anti-tumor immunity. Vaccine 2008;26:5046-57.  Back to cited text no. 27
    


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