Immunological Implications of the use of Plant Lectins for Drug and Vaccine Targeting to the Gastrointestinal Tract

Lectin-modified drug delivery systems - Recent applications in the oncology field

Chemotherapy with cytotoxic drugs remains the core treatment for cancer but, due to the difficulty to find general and usable biochemical differences between cancer cells and normal cells, many of these drugs are associated with lack of specificity, resulting in side effects and collateral cytotoxicity that impair patients' adherence to therapy. Novel cancer treatments in which the cytotoxic effect is maximized while adverse effects are reduced can be implemented by developing targeted therapies that exploit the specific features of cancer cells, such as the typical expression of aberrant glycans. Modification of drug delivery systems with lectins is one of the strategies to implement targeted chemotherapies, as lectins are able to specifically recognize and bind to cancer-associated glycans expressed at the surface of cancer cells, guiding the drug treatment towards these cells and not affecting healthy ones. In this paper, recent advances on the development of lectin-modified drug delivery systems for targeted cancer treatments are thoroughly reviewed, with a focus on their properties and performance in diverse applications, as well as their main advantages and limitations. The synthesis and analytical characterization of the cited lectin-modified drug delivery systems is also briefly described. A comparison with free-drug treatments and with antibody-modified drug delivery systems is presented, emphasizing the advantages of lectin-modified drug delivery systems. Main constraints and potential challenges of lectin-modified drug delivery systems, including key difficulties for clinical translation of these systems, and the required developments in this area, are also signalled.

In-silico structural inhibition of ACE-2 binding site of SARS-CoV-2 and SARS-CoV-2 Omicron spike protein by lectin antiviral dyad system to treat COVID-19

Spike glycoprotein of SARS-CoV-2 binds ACE-2 receptors via its receptor-binding-domain (RBD) and mediates virus-to-host cell fusion. Recently emerged omicron variant of SARS-CoV-2 possess around 30 mutations in spike protein where N501Y tremendously increases viral infectivity and transmission. Lectins interact with glycoproteins and mediate innate immunity displaying antiviral, antibacterial and anticarcinogenic properties. In this study, we analysed the potential of lectin, and lectin-antibody (spike-specific) complex to inhibit the ACE-2 binding site of wild and N501Y mutated spike protein by utilizing in-silico molecular docking and simulation approach. Docking of lectin at reported ACE-2 binding spike-RBD residues displayed the ZDock scores of 1907 for wild and 1750 for N501Y mutated spike-RBD. Binding of lectin with antibody to form proposed dyad complex gave ZDock score of 1174 revealing stable binding. Docking of dyad complex with wild and N501Y mutated spike-RBD, at lectin and antibody individually, showed high efficiency binding hence, effective structural inhibition of spike-RBD. MD simulation of 100ns of each complex proved high stability of complexes with RMSD values ranging from 0.2 -1.5nm. Consistent interactions of lead ACE-2 binding spike residues with lectin during simulation disclosed efficient structural inhibition by lectin against formation of spike RBD-ACE-2 complex.Hence, lectins along with their ability to induce innate immunity against spike glycoprotein can structurally inhibit the spike-RBD when given as lectin-antibody dyad system and thus can be developed into a dual effect treatment against COVID-19. Moreover, the high binding specificity of this system with spike-RBD can be exploited for development of diagnostic and drug-delivery systems.

Immunostimulant plant proteins: Potential candidates as vaccine adjuvants

The COVID-19 pandemic is shaking up global scientific structures toward addressing antibiotic resistance threats and indicates an urgent need to develop more cost-effective vaccines. Vaccine adjuvants play a crucial role in boosting immunogenicity and improving vaccine efficacy. The toxicity and adversity of most adjuvant formulations are the major human immunization problems, especially in routine pediatric and immunocompromised patients. The present review focused on preclinical studies of immunoadjuvant plant proteins in use with antiparasitic, antifungal, and antiviral vaccines. Moreover, this report outlines the current perspective of immunostimulant plant protein candidates that can be used by researchers in developing new generations of vaccine-adjuvants. Future clinical studies are required to substantiate the plant proteins' safety and applicability as a vaccine adjuvant in pharmaceutical manufacturing.

Protein-Based Adjuvants for Vaccines as Immunomodulators of the Innate and Adaptive Immune Response: Current Knowledge, Challenges, and Future Opportunities

New-generation vaccines, formulated with subunits or nucleic acids, are less immunogenic than classical vaccines formulated with live-attenuated or inactivated pathogens. This difference has led to an intensified search for additional potent vaccine adjuvants that meet safety and efficacy criteria and confer long-term protection. This review provides an overview of protein-based adjuvants (PBAs) obtained from different organisms, including bacteria, mollusks, plants, and humans. Notably, despite structural differences, all PBAs show significant immunostimulatory properties, eliciting B-cell- and T-cell-mediated immune responses to administered antigens, providing advantages over many currently adopted adjuvant approaches. Furthermore, PBAs are natural biocompatible and biodegradable substances that induce minimal reactogenicity and toxicity and interact with innate immune receptors, enhancing their endocytosis and modulating subsequent adaptive immune responses. We propose that PBAs can contribute to the development of vaccines against complex pathogens, including intracellular pathogens such as Mycobacterium tuberculosis, those with complex life cycles such as Plasmodium falciparum, those that induce host immune dysfunction such as HIV, those that target immunocompromised individuals such as fungi, those with a latent disease phase such as Herpes, those that are antigenically variable such as SARS-CoV-2 and those that undergo continuous evolution, to reduce the likelihood of outbreaks.

Immunoadjuvant and Humoral Immune Responses of Garlic (Allium sativum L.) Lectins upon Systemic and Mucosal Administration in BALB/c Mice

Dietary food components have the ability to affect immune function; following absorption, specifically orally ingested dietary food containing lectins can systemically modulate the immune cells and affect the response to self- and co-administered food antigens. The mannose-binding lectins from garlic (Allium sativum agglutinins; ASAs) were identified as immunodulatory proteins in vitro. The objective of the present study was to assess the immunogenicity and adjuvanticity of garlic agglutinins and to evaluate whether they have adjuvant properties in vivo for a weak antigen ovalbumin (OVA). Garlic lectins (ASA I and ASA II) were administered by intranasal (50 days duration) and intradermal (14 days duration) routes, and the anti-lectin and anti-OVA immune (IgG) responses in the control and test groups of the BALB/c mice were assessed for humoral immunogenicity. Lectins, co-administered with OVA, were examined for lectin-induced anti-OVA IgG response to assess their adjuvant properties. The splenic and thymic indices were evaluated as a measure of immunomodulatory functions. Intradermal administration of ASA I and ASA II had showed a four-fold and two-fold increase in anti-lectin IgG response, respectively, vs. the control on day 14. In the intranasal route, the increases were 3-fold and 2.4-fold for ASA I and ASA II, respectively, on day 50. No decrease in the body weights of animals was noticed; the increases in the spleen and thymus weights, as well as their indices, were significant in the lectin groups. In the adjuvanticity study by intranasal administration, ASA I co-administered with ovalbumin (OVA) induced a remarkable increase in anti-OVA IgG response (~six-fold; p < 0.001) compared to the control, and ASA II induced a four-fold increase vs. the control on day 50. The results indicated that ASA was a potent immunogen which induced mucosal immunogenicity to the antigens that were administered intranasally in BALB/c mice. The observations made of the in vivo study indicate that ASA I has the potential use as an oral and mucosal adjuvant to deliver candidate weak antigens. Further clinical studies in humans are required to confirm its applicability.

Chitosan-Based Nanoparticles Against Viral Infections

Viral infections, in addition to damaging host cells, can compromise the host immune system, leading to frequent relapse or long-term persistence. Viruses have the capacity to destroy the host cell while liberating their own RNA or DNA in order to replicate within additional host cells. The viral life cycle makes it challenging to develop anti-viral drugs. Nanotechnology-based approaches have been suggested to deal effectively with viral diseases, and overcome some limitations of anti-viral drugs. Nanotechnology has enabled scientists to overcome the challenges of solubility and toxicity of anti-viral drugs, and can enhance their selectivity towards viruses and virally infected cells, while preserving healthy host cells. Chitosan is a naturally occurring polymer that has been used to construct nanoparticles (NPs), which are biocompatible, biodegradable, less toxic, easy to prepare, and can function as effective drug delivery systems (DDSs). Furthermore, chitosan is Generally Recognized as Safe (GRAS) by the US Food and Drug Administration (U.S. FDA). Chitosan NPs have been used in drug delivery by the oral, ocular, pulmonary, nasal, mucosal, buccal, or vaginal routes. They have also been studied for gene delivery, vaccine delivery, and advanced cancer therapy. Multiple lines of evidence suggest that chitosan NPs could be used as new therapeutic tools against viral infections. In this review we summarize reports concerning the therapeutic potential of chitosan NPs against various viral infections.

Galactosamine-modified PEG-PLA/TPGS micelles for the oral delivery of curcumin

In this study, galactosamine-modified poly(ethylene glycol)-poly(lactide) (Gal-PEG-PLA) polymers were synthesized and Gal-PEG-PLA/D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) micelles named as GPP micelles were designed to promote the oral absorption of a hydrophobic drug, curcumin (CUR). CUR-loaded Gal-PEG-PLA/TPGS micelles (CUR@GPP micelles) were fabricated using the thin-film dispersion method. CUR@GPP micelles had a size of about 100 nm, a near-neutral zeta potential, drug loading (DL) of 14.6%, and sustained release properties. GPP micelles with high Gal density (GPP3 micelles) were superior in facilitating uptake in epithelial cells and improving intestinal permeation. In situ intestinal absorption studies suggested that the jejunum and ileum were the best absorption segments in the intestinal tract. Additionally, biodistribution results revealed that GPP3 micelles could be remarkably taken up by the jejunum and ileum. Pharmacokinetics revealed that the maximum plasma concentration (C_max) and the area under the plasma concentration-time curve from 0 to 24 h (AUC_0-24) for CUR@GPP3 micelles were both significantly increased, and that the relative bioavailability of CUR@GPP3 micelles to CUR-loaded mPEG-PLA/TPGS micelles (CUR@PP micelles) was 258.8%. Furthermore, CUR-loaded micelles could reduce damage to the liver and intestinal tissues. This study highlights the importance of Gal content in the design of targeting nanocarrier Gal-modified micelles, which have broad prospects for oral delivery of hydrophobic drugs. Therefore, they could serve as a promising candidate for targeted delivery to the liver.

O-2'-hydroxypropyltrimethyl ammonium chloride chitosan nanoparticles for the delivery of live Newcastle disease vaccine

A novel complex chitosan derivative, O-2'-hydroxypropyltrimethyl ammonium chloride chitosan (O-2'-HACC), was synthesized and used to make nanoparticles as a delivery vehicle for live attenuated Newcastle disease vaccine. We found that O-2'-HACC had high antimicrobial activity, low toxicity, and a high safety level. Newcastle disease virus (NDV) was then encapsulated in the O-2'-HACC nanoparticles (NDV/La Sota-O-2'-HACC-NPs) by the ionic crosslinking method, and the properties of the resulting nanoparticles were determined by transmission electron microscopy, Zeta potential analysis, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and X-ray diffraction. NDV/La Sota-O-2'-HACC-NPs had regular spherical morphologies and high stability, with an encapsulation efficiency of 95.68 ± 2.2% and a loading capacity of 58.75 ± 4.03%. An in vitro release assay indicated that release of NDV from NDV/La Sota-O-2'-HACC-NPs occurred slowly. Specific pathogen-free chickens immunized with NDV/La Sota-O-2'-HACC-NPs intranasally had much stronger cellular, humoral and mucosal immune responses than did those immunized intramuscularly or with live attenuated Newcastle disease vaccine. NDV/La Sota-O-2'-HACC-NPs are a novel drug delivery carrier with immense potential in medical applications.

Distribution patterns of carbohydrates in murine glycocalyx

Enterocytes are unique cells governing an array of processes. They are covered by the gut glycocalyx, which is an extraneous carbohydrate-rich coat and an integral part of the plasma membrane. The intestinal glycocalyx and secreted mucins constitute a glycosylated milieu which has a number of physiological and protective functions. One of the important functions of the glycocalyx is its barrier function against microbial adherence to different membrane glycolipids. Thus, the glycocalyx is an important part of the mucosal immune system in newborns. The aim of our study was to identify the carbohydrates in the small bowel glycocalyx of Balb/c mice at different ages. We used plant lectins with different sugar specificities. Fluorescein-labelled lectins binding different carbohydrate moieties were detected using confocal laser scanning microscopy. Biotinilated lectins were used for transmission electron microscopy observations of the constituents of the gut glycocalyx at different periods of postnatal development in mice. Different carbohydrate moieties that were identified in the murine intestinal glycocalyx followed different distribution patterns and characteristics. Carbohydrates present on the mucus surface depended on tissue localization, cell type and stage of development. The distribution and mucins glycosylation could be of interest in analysing the response of the mucosal barrier to intestinal pathogens causing infection or inflammation.

Development and characterization of LTA-appended chitosan nanoparticles for mucosal immunization against hepatitis B

The present study was aimed at exploring the targeting potential of LTA-anchored chitosan nanoparticles (CH-NP) specifically to M cell following oral immunization. The lectinized CH-NP exhibited 7-29% coupling capacity depending upon the amount of glutaraldehyde added. Induction of the mucosal immunity was assessed by estimating secretory IgA level in the salivary, intestinal and vaginal secretions, and cytokine (IL-2 and IFN-γ) levels in the spleen homogenates. The results demonstrated that LTA-anchored CH-NP elicited strong humoral and cellular responses and hence could be a competent carrier-adjuvant delivery system for oral mucosal immunization against Hepatitis B.

Intestinal receptor targeting for peptide delivery: an expert's personal perspective on reasons for failure and new opportunities

The technology has been available more than 25 years that would enable the oral delivery of vaccines, proteins and peptides, thus avoiding the need for injection. To this day, injection is still the mode of delivery, yet not the main mode of choice. This review focuses on several of the potential modes for oral delivery of peptides, proteins and vaccines. Additionally, the review will provide the reader with an insight into the problems and potential solutions for several of these modes of oral delivery of peptides and proteins.

New insights in mucosal vaccine development

Mucosal surfaces are the major entrance for infectious pathogens and therefore mucosal immune responses serve as a first line of defence. Most current immunization procedures are obtained by parenteral injection and only few vaccines are administered by mucosal route, because of its low efficiency. However, targeting of mucosal compartments to induce protective immunity at both mucosal sites and systemic level represents a great challenge. Major efforts are made to develop new mucosal candidate vaccines by selecting appropriate antigens with high immunogenicity, designing new mucosal routes of administration and selecting immune-stimulatory adjuvant molecules. The aim of mucosal vaccines is to induce broad potent protective immunity by specific neutralizing antibodies at mucosal surfaces and by induction of cellular immunity. Moreover, an efficient mucosal vaccine would make immunization procedures easier and be better suited for mass administration. This review focuses on contemporary developments of mucosal vaccination approaches using different routes of administration.

Formulation design considerations for oral vaccines

Whilst oral vaccination is a potentially preferred route in terms of patient adherence and mass vaccination, the ability to formulate effective oral vaccines remains a challenge. The primary barrier to oral vaccination is effective delivery of the vaccine through the GI tract owing to the many obstacles it presents, including low pH, enzyme degradation and bile-salt solubilization, which can result in breakdown/deactivation of a vaccine. For effective immune responses after oral administration, particulates need to be taken up by the M cells however, these are few in number. To enhance M-cell uptake, particle characteristics can be optimized with particle size, surface charge, targeting groups and bioadhesive properties all being considerations. Yet improved uptake may not translate into enhanced immune responses and formulating particulates with inherent adjuvant properties can offer advantages. Within this article, we establish the options available for consideration when building effective oral particulate vaccines.

Application of Ulex europaeus agglutinin I-modified liposomes for oral vaccine: Ex Vivo bioadhesion and in Vivo immunity

The conjugation of Ulex europaeus agglutinin I (UEAI) onto surface of liposomes has been demonstrated to effectively improve the intestinal absorption of antigen, subsequently induced strong mucosal and systemic immune responses. In this context, we prepared bovine serum albumin (BSA)-encapsulating UEAI-modified liposomes (UEAI-LIP) and unmodified ones (LIP). The specific bioadhesion on mice gastro-intestinal mucosa was studied ex vivo. An important increase of interaction between UEAI-conjugated liposomes and the intestinal segments with Peyer's Patches (PPs) was observed compared with the unconjugated one (p<0.01). However, under the presence of α-L-fucose, which is the reported specific sugar for UEAI, specifically inhibited the activity of these conjugates. The immune-stimulating activity in vivo was studied by measuring immunoglobulin G (IgG) levels in serum and immunoglobulin A (IgA) levels in intestinal mucosal secretions following oral administration of BSA solution, LIP and UEAI-LIP in mice. Results indicate that antigen encapsulated in liposomes, especially the UEAI-modified ones, was favorable for inducing immune response. At 42 d after the first immunization, the highest IgG and IgA antibody levels produced by UEAI-LIP occurred, respectively showing 4.4-fold and 5-fold higher levels compared to those of the groups receiving BSA alone. This data demonstrated high potential of UEAI-modified liposomes for their use as carrier for oral vaccines.

Phenotypic localization of distinct DC subsets in mouse Peyer Patch

Peyer's patch have been extensively studied as a major inductive site for mucosal immunity within the small intestine. The intestinal mucosa contains numerous dendritic cells, which induce either protective immunity to infectious agents or tolerance to innocuous antigens, including food and commensal bacteria. Although during the past few years, several subsets of human mucosal dendritic cells have been described, a precise characterization of the different mouse mucosal dendritic cells subpopulations remains to be achieved with regard to their phenotype and localization in Peyer's patch. In this report, we have investigated by immunofluorescence on cryosection and by flow cytometry, the phenotype and the localization of dendritic cells into Peyer's patch of C57Bl/6 mouse intestine using dendritic cells markers. Positive and double staining for CD11c and BDCA-2, pDC/IPC, DC-LAMP, DC-SIGN, TLR8 and Langerin have been observed revealing new mouse intestinal DC subsets. This study provides new insight in the understanding of mucosal immune responses induced by natural processes as infections but also new perspectives for the evaluation of oral vaccines.

In planta production of plant-derived and non-plant-derived adjuvants

Recombinant antigen production in plants is a safe and economically sound strategy for vaccine development, particularly for oral/mucosal vaccination, but subunit vaccines usually suffer from weak immunogenicity and require adjuvants that escort the antigens, target them to relevant sites and/or activate antigen-presenting cells for elicitation of protective immunity. Genetic fusions of antigens with bacterial adjuvants as the B subunit of the cholera toxin have been successful in inducing protective immunity of plant-made vaccines. In addition, several plant compounds, mainly plant defensive molecules as lectins and saponins, have shown strong adjuvant activities. The molecular diversity of the plant kingdom offers a vast source of non-bacterial compounds with adjuvant activity, which can be assayed in emerging plant manufacturing systems for the design of new plant vaccine formulations.

M-cell targeting of whole killed bacteria induces protective immunity against gastrointestinal pathogens

As the majority of human pathogens infect via a mucosal surface, delivery of killed vaccines by mucosal routes could potentially improve protection against many such organisms. Our ability to develop effective killed mucosal vaccines is inhibited by a lack of adjuvants that are safe and effective in humans. The Ulex europaeus agglutinin I (UEA-I) lectin specifically binds M cells lining the murine gastrointestinal tract. We explored the potential for M-cell-targeted vaccination of whole, killed Helicobacter pylori, the main causative agent of peptic ulcer disease and gastric cancer, and Campylobacter jejuni, the most common cause of diarrhea. Oral delivery of UEA-I-agglutinated H. pylori or C. jejuni induced a significant increase in both serum and intestinal antibody levels. This elevated response (i) required the use of whole bacteria, as it did not occur with lysate; (ii) was not mediated by formation of particulate clumps, as agglutination with a lectin with a different glycan specificity had no effect; and (iii) was not due to lectin-mediated, nonspecific immunostimulatory activity, as UEA-I codelivery with nonagglutinated bacteria did not enhance the response. Vaccination with UEA-I-agglutinated, killed whole H. pylori induced a protective response against subsequent live challenge that was as effective as that induced by cholera toxin adjuvant. Moreover, vaccination against C. jejuni by this approach resulted in complete protection against challenge in almost all animals. We believe that this is the first demonstration that targeting of whole killed bacteria to mucosal M cells can induce protective immunity without the addition of an immunostimulatory adjuvant.

Opportunities and challenges in vaccine delivery

This report is a distillation of the workshop 'Opportunities and Challenges in Vaccine Delivery', organised by EUFEPS/FIP and co-sponsored by AAPS and CRS, in Archamps, France, September 2008. The aim of this workshop was to bridge knowledge gaps between the different disciplines involved in the delivery of vaccines. Here, key challenges include target identification, mapping the needs and target population, the development and harmonisation of predictive read-out systems and surrogate markers for protection, and improving antigen immunogenicity, delivery and stability. The workshop underlined the need and possibilities of a multidisciplinary approach to meet these challenges. This involves increasing our understanding of immunological mechanisms, the development of advanced delivery systems and adjuvant technologies, and insight into the regulatory guidelines and target population. Based upon this knowledge, future vaccinology can increasingly focus on rational design of antigens, adjuvants and delivery systems, which will lead to new and improved vaccines.

Micro- and nanoparticle-based vaccines for hepatitis B

The incredible success of vaccinations in contributing to public health is undeniable. In fact, vaccines are the most cost-effective public health tool for disease prevention because their cost is less than the combined costs of treatment, hospitalization, and time loss from work. However, despite the availability of vaccines, cost per dose is a factor limiting the success of global vaccination campaigns, as are the limitations imposed by the need of delivering multiple vaccine doses. A number of approaches are being tested particularly for the delivery of subunit vaccines, and in recent years, a number of groups have devoted their efforts to develop nano/microparticles prepared from biodegradable and biocompatible polymers as vaccine delivery systems with the goal of inducing both humoral and cellular immune responses. Some important properties of biodegradable polymers are their documented safety history, biocompatibility, and an ability to provide controlled time/rate of antigen release and polymer degradation. The most extensively studied polymer used for encapsulating vaccine antigens is poly (lactide-co-glycolide acid) (PLGA). This chapter deals in brief with efforts targeting the use of PLGA micro-and nanoparticles for the delivery of hepatitis B surface antigen.

Delivery systems and adjuvants for oral vaccines

The oral route is the ideal means of delivering prophylactic and therapeutic vaccines, offering significant advantages over systemic delivery. Most notably, oral delivery is associated with simple administration and improved safety. In addition, unlike systemic immunisation, oral delivery can induce mucosal immune responses. However, the oral route of vaccine delivery is the most difficult because of the numerous barriers posed by the gastrointestinal tract. To facilitate effective immunisation with peptide and protein vaccines, antigens must be protected, uptake enhanced and the innate immune response activated. Numerous delivery systems and adjuvants have been evaluated for oral vaccine delivery, including live vectors, inert particles and bacterial toxins. Although developments in oral vaccines have been disappointing so far, in terms of the generation of products, the availability of a range of novel delivery systems offers much greater hope for the future development of improved oral vaccines.

The role of adjuvants in the development of mucosal vaccines

It is well-established that most pathogens that cause infectious diseases enter the host via mucosal membranes of the respiratory, digestive and genital tracts. Some parenterally administered vaccines induce protection against mucosal pathogens. However, there is increasing evidence that mucosal protection is better afforded by mucosal vaccination, particularly for the induction of memory responses. Mucosal vaccines must pass several difficult hurdles before entering the host and inducing an effective and protective immune response. This review deals with present and past efforts in devising effective mucosal vaccines using delivery systems and immunopotentiating adjuvants for protein-based vaccines. The paper will conclude with the authors' opinion on how the field will or should progress in the future and what will be the required components of ideal future mucosal vaccines that can induce immunological memory.

Lectin anchored stabilized biodegradable nanoparticles for oral immunization 1. Development and in vitro evaluation

The investigation comprises development of a stable and targeted formulation of HBsAg for the oral immunization against Hepatitis B. PLGA nanoparticles bearing HBsAg was prepared by double emulsion method. The antigen was protected from organic/aqueous interface by using protein stabilizer, trehalose. The acidic environment generated within PLGA nanoparticles was neutralized by co-encapsulation of a basic additive, Mg(OH)(2) which provides an additional stabilization to the antigen especially against acid induced antigen inactivation. Furthermore, lectin from Arachis hypogaea (PNA) was anchored on to the surface of the HBsAg loaded nanoparticles in order to enhance their affinity towards the antigen presenting cells of the Peyer's patches. The developed system was characterized for shape, size and loading efficiency. The antigen integrity was assessed by using SDS-PAGE followed by isoelectric focusing analysis. Bovine submaxillary mucin (BSM) was used as a biological model for in vitro ligand affinity determination and activity studies. The lectin anchored nanoparticles exhibited 52.18+/-4.73% loading while ligand density was estimated to be of 17.90+/-1.14 microg/mg. The results suggest that HBsAg can be successfully stabilized by co-encapsulation of an appropriate protein stabilizer, i.e. trehalose and a basic additive, Mg(OH)(2). The ligand-coupled nanoparticles demonstrated approximately four folds increase in degree interaction with the BSM as compared to plain nanoparticles. Additionally, the nanoparticles maintained their intrinsic sugar specificity as associated due to lectin (PNA).