Elsevier

Biomaterials

Volume 33, Issue 18, June 2012, Pages 4762-4772
Biomaterials

Tailoring the immune response by targeting C-type lectin receptors on alveolar macrophages using “pathogen-like” amphiphilic polyanhydride nanoparticles

https://doi.org/10.1016/j.biomaterials.2012.03.027Get rights and content

Abstract

C-type lectin receptors (CLRs) offer unique advantages for tailoring immune responses. Engagement of CLRs regulates antigen presenting cell (APC) activation and promotes delivery of antigens to specific intracellular compartments inside APCs for efficient processing and presentation. In these studies, we have designed an approach for targeted antigen delivery by decorating the surface of polyanhydride nanoparticles with specific carbohydrates to provide pathogen-like properties. Two conserved carbohydrate structures often found on the surface of respiratory pathogens, galactose and di-mannose, were used to functionalize the surface of polyanhydride nanoparticles and target CLRs on alveolar macrophages (AMϕ), a principle respiratory tract APC. Co-culture of functionalized nanoparticles with AMϕ significantly increased cell surface expression of MHC I and II, CD86, CD40 and the CLR CIRE over non-functionalized nanoparticles. Di-mannose and galactose functionalization also enhanced the expression of the macrophage mannose receptor (MMR) and the macrophage galactose lectin, respectively. This enhanced AMϕ activation phenotype was found to be dependent upon nanoparticle internalization. Functionalization also promoted increased AMϕ production of the pro-inflammatory cytokines IL-1β, IL-6 and TNF-α. Additional studies demonstrated the requirement of the MMR for the enhanced cellular uptake and activation provided by the di-mannose functionalized nanoparticles. Together, these data indicate that targeted engagement of MMR and other CLRs is a viable strategy for enhancing the intrinsic adjuvant properties of nanovaccine adjuvants and promoting robust pulmonary immunity.

Introduction

Acute respiratory infections cause 4.25 million deaths worldwide every year [1]. A critical need exists for the development of efficacious intranasal vaccines against respiratory pathogens capable of inducing robust and protective mucosal immunity. In this regard, there is growing interest in the development of vaccines that can be easily administered to the site of infection in order to elicit both local and systemic immune responses [2], [3], [4], [5].

The study of alveolar macrophages (AMϕ), a type of antigen presenting cell (APC) in the respiratory tract, is central to the development of intranasal vaccines. AMϕ constitute more than 80% of the total cells obtained by bronchoalveolar lavage of a healthy individual and they constitutively migrate from the lung to the draining lymph nodes (DLN) [6], [7], [8]. Indeed, AMϕ containing bacteria appear in the pulmonary DLN prior to the onset of pathogen-induced DC migration, thereby making them integral to the establishment of protective pulmonary immune responses [6]. AMϕ are equipped to detect pathogens with the aid of pattern recognition receptors (PRRs) that recognize pathogen-associated molecular patterns (PAMPs) [9]. One family of PRRs found on AMϕ, known as C-type lectin receptors (CLRs), recognize conserved carbohydrate structures, including mannose and galactose, found on the surface of many respiratory pathogens, such as Yersinia pestis, Mycobacterium tuberculosis, Streptococcus pneumoniae and influenza viruses [10], [11], [12], [13], [14]. CLRs also function as phagocytic receptors and include members of the mannose receptor family and DC-SIGN (dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin) [15]. Depending on the specific CLR, ligand binding initiates downstream signaling cascades that promote immune cell migration to the DLN as well as antigen processing and presentation via MHC I and/or MHC II to prime naïve T cells [16], [17], [18], [19], [20].

Several research groups have explored CLR targeting as a vaccine design strategy to promote efficient delivery of cargo to intracellular compartments responsible for antigen processing and presentation [21], [22], [23], [24], [25], [26], [27], [28], [29]. Many studies have demonstrated the effectiveness of using antibodies [22] or mannoproteins from pathogens [26] to target CLRs and activate APCs. However, only a limited number report the use of carbohydrate-functionalized vaccine carriers as part of an improved adjuvant for intranasal vaccines [21], [24]. Work published by Jiang et al. indicated that alveolar macrophages could recognize mannosylated chitosan microparticles when delivered intranasally [24]. Unfortunately, mechanistic studies demonstrating the engagement of the mannose receptor on AMϕ by these particles were not performed. Here, we describe functionalization of polyanhydride nanoparticles with two conserved carbohydrate structures commonly found on the surface of respiratory pathogens, di-mannose and galactose. We also investigate the mechanisms by which these functionalized polyanhydride nanoparticles are internalized by and influence the activation of AMϕ.

Section snippets

Materials

The chemicals needed for monomer synthesis, polymerization and nanoparticle fabrication included 1,6-dibromohexane, triethylene glycol, 4-p-hydroxybenzoic acid, and 1-methyl-2-pyrrolidinone; these were purchased from Sigma–Aldrich (St. Louis, MO); 4-p-fluorobenzonitrile was obtained from Apollo Scientific (Cheshire, UK); toluene, sulfuric acid, acetonitrile, dimethyl formamide, acetic anhydride, methylene chloride, pentane, and potassium carbonate were obtained from Fisher Scientific (Fairlawn,

Synthesis and characterization of functionalized polyanhydride nanoparticles

Amphiphilic 50:50 CPTEG:CPH copolymer was synthesized as described previously [31]. The molecular weight (Mw) of the copolymer was 8000 Da and 1H NMR spectra of the copolymer were consistent with previously published data [31], [33], [35]. Particle morphology was evaluated by SEM and was found to be consistent with previously published results ([21], [33], [43] and data not shown). The average diameter of the non-functionalized nanoparticles was 163 ± 24 nm with a ζ-potential of −23 ± 2.5 mV

Discussion

In the present work, we have designed an approach to targeted antigen delivery by functionalizing the surface of polyanhydride nanoparticles with specific carbohydrates to enable the nanoparticles to engage C-type lectin receptors on AMϕ. Our rationale is that receptor-mediated engagement of nanoparticles will enhance their uptake and the activation of AMϕ, leading to the induction of robust immune responses in the respiratory tract.

Co-culture of functionalized nanoparticles with AMϕ

Conclusions

The approach outlined in this present work demonstrates that rational design of efficacious vaccine adjuvants can be achieved by targeting CLRs on APCs. Specifically, we describe the functionalization of polyanhydride nanoparticles with two conserved carbohydrate structures commonly found on the surface of respiratory pathogens, di-mannose and galactose. The addition of these carbohydrates significantly enhanced the intrinsic adjuvant activity of our polyanhydride nanovaccine platform by

Acknowledgments

The authors would like to thank the United States Army Medical Research and Materiel Command for financial support (Grant No. W81XWH-10-1-0806). The authors are grateful to Shawn Rigby for his expertise in flow cytometry and to Dr. Mary Ann McDowell of the University of Notre Dame for generously providing the MMR−/− mice. BN acknowledges the Balloun Professorship in Chemical and Biological Engineering and NLBP acknowledges the Wilkinson Professorship of Interdisciplinary Engineering.

References (62)

  • M. Torres et al.

    Polyanhydride microparticles enhance dendritic cell antigen presentation and activation

    Acta Biomaterialia

    (2011)
  • L.K. Petersen et al.

    Activation of innate immune responses in a pathogen-mimicking manner by amphiphilic polyanhydride nanoparticle adjuvants

    Biomaterials

    (2011)
  • A. Lanzavecchia

    Mechanisms of antigen uptake for presentation

    Curr Opin Immunol

    (1996)
  • S.J. van Vliet et al.

    Sweet preferences of MGL: carbohydrate specificity and function

    Trends Immunol

    (2008)
  • J.M. Cavaillon

    Cytokines and macrophages

    Biomed Pharmacother

    (1994)
  • P.C. Dedon et al.

    Reactive nitrogen species in the chemical biology of inflammation

    Arch Biochem Biophys

    (2004)
  • E. Walter et al.

    Hydrophilic poly(dl-lactide-co-glycolide) microspheres for the delivery of DNA to human-derived macrophages and dendritic cells

    J Control Release

    (2001)
  • W.L. Foundation

    ARIs overview New York, NY: the acute respiratory infections atlas

    (2010)
  • T. Ichinohe et al.

    Induction of cross-protective immunity against influenza A virus H5N1 by an intranasal vaccine with extracts of mushroom mycelia

    J Med Virol

    (2010)
  • M.L. Oliveira et al.

    Intranasal vaccines for protection against respiratory and systemic bacterial infections

    Expert Rev Vaccines

    (2007)
  • A.C. Kirby et al.

    Alveolar macrophages transport pathogens to lung draining lymph nodes

    J Immunol

    (2009)
  • A.C. Kirby et al.

    CD11b regulates recruitment of alveolar macrophages but not pulmonary dendritic cells after pneumococcal challenge

    J Infect Dis

    (2006)
  • S. Worgall et al.

    Role of alveolar macrophages in rapid elimination of adenovirus vectors administered to the epithelial surface of the respiratory tract

    Hum Gene Ther

    (1997)
  • L.P. Nicod

    Pulmonary defence mechanisms

    Respiration

    (1999)
  • K.M. Dobos et al.

    Evidence for glycosylation sites on the 45-kilodalton glycoprotein of Mycobacterium tuberculosis

    Infect Immun

    (1995)
  • J.L. Hartley et al.

    Chemical and physical properties of lipopolysaccharide of Yersinia pestis

    J Bacteriol

    (1974)
  • C.J. Lee et al.

    Chemical structure of and immune response to polysaccharides of Streptococcus pneumoniae

    Rev Infect Dis

    (1981)
  • A. Matsumoto et al.

    Carbohydrates of influenza virus hemagglutinin: structures of the whole neutral sugar chains

    Biochemistry

    (1983)
  • R.T. Schwarz et al.

    Carbohydrates of influenza virus. I. Glycopeptides derived from viral glycoproteins after labeling with radioactive sugars

    J Virol

    (1977)
  • A. Cambi et al.

    How C-type lectins detect pathogens

    Cell Microbiol

    (2005)
  • T.B. Geijtenbeek et al.

    Signalling through C-type lectin receptors: shaping immune responses

    Nat Rev Immunol

    (2009)
  • Cited by (81)

    • Nanomaterials and immune system

      2022, Immunomodulatory Effects of Nanomaterials: Assessment and Analysis
    • Polymer-based bionanomaterials for targeted drug delivery

      2022, Fundamentals of Bionanomaterials
    • Fucosylated lipid nanocarriers loaded with antibiotics efficiently inhibit mycobacterial propagation in human myeloid cells

      2021, Journal of Controlled Release
      Citation Excerpt :

      The MMR is a mannose/fucose-binding CLR that is highly expressed on AM and mediates the initial recognition and phagocytosis of Mtb [18–20]. Although previous investigations followed the approach of targeting AM via the MMR [21–23], to date there is no comprehensive study addressing the targeting mechanism and the drug delivery potential of CLR-targeting nanocarriers. Hence, in this study we evaluated the potency of fucosylated lipid nanocarriers to target MMR-positive myeloid cells, such as AM, and to selectively deliver levofloxacin to these cells as an innovative approach to treat Mtb infection.

    View all citing articles on Scopus
    View full text