Vaccine Research Articles

Multifunctional Mycobacterial Topoisomerases with Distinctive Features.

Tuberculosis (TB) continues to be a major cause of death worldwide despite having an effective combinatorial therapeutic regimen and vaccine. Being one of the most successful human pathogens, Mycobacterium tuberculosis retains the ability to adapt to diverse intracellular and extracellular environments encountered by it during infection, persistence, and transmission. Designing and developing new therapeutic strategies to counter the emergence of multidrug-resistant and extensively drug-resistant TB remains a major task. DNA topoisomerases make up a unique class of ubiquitous enzymes that ensure steady-state level supercoiling and solve topological problems occurring during DNA transactions in cells. They continue to be attractive targets for the discovery of novel classes of antibacterials and to develop better molecules from existing drugs by virtue of their reaction mechanism. The limited repertoire of topoisomerases in M. tuberculosis, key differences in their properties compared to topoisomerases from other bacteria, their essentiality for the pathogen's survival, and validation as candidates for drug discovery provide an opportunity to exploit them in drug discovery efforts. The present review provides insights into their organization, structure, function, and regulation to further efforts in targeting them for new inhibitor discovery. First, the structure and biochemical properties of DNA gyrase and Topoisomerase I (TopoI) of mycobacteria are described compared to the well-studied counterparts from other bacteria. Next, we provide an overview of known inhibitors of DNA gyrase and emerging novel bacterial topoisomerase inhibitors (NBTIs). We also provide an update on TopoI-specific compounds, highlighting mycobacteria-specific inhibitors.

HLA I immunopeptidome of synthetic long peptide pulsed human dendritic cells for therapeutic vaccine design

Synthetic long peptides (SLPs) are a promising vaccine modality that exploit dendritic cells (DC) to treat chronic infections or cancer. Currently, the design of SLPs relies on in silico prediction and multifactorial T cells assays to determine which SLPs are best cross-presented on DC human leukocyte antigen class I (HLA-I). Furthermore, it is unknown how TLR ligand-based adjuvants affect DC cross-presentation. Here, we generated a unique, high-quality immunopeptidome dataset of human DCs pulsed with 12 hepatitis B virus (HBV)-based SLPs combined with either a TLR1/2 (Amplivant®) or TLR3 (PolyI:C) ligand. The obtained immunopeptidome reflected adjuvant-induced differences, but no differences in cross-presentation of SLPs. We uncovered dominant (cross-)presentation on B-alleles, and identified 33 unique SLP-derived HLA-I peptides, several of which were not in silico predicted and some were consistently found across donors. Our work puts forward DC immunopeptidomics as a valuable tool for therapeutic vaccine design.

Architects of immunity: How dendritic cells shape CD8+ T cell fate in cancer.

Immune responses against cancer are dominated by T cell exhaustion and dysfunction. Recent advances have underscored the critical role of early priming interactions in establishing T cell fates. In this review, we explore the importance of dendritic cell (DC) signals in specifying CD8+ T cell fates in cancer, drawing on insights from acute and chronic viral infection models. We highlight the role of DCs in lymph nodes and tumors in maintaining stem-like CD8+ T cells, which are critical for durable antitumor immune responses. Understanding how CD8+ T cell fates are determined will enable the rational design of immunotherapies, particularly therapeutic cancer vaccines, that can modulate DC-T cell interactions to generate beneficial CD8+ T cell fates.

Phenomenological Modeling of Antibody Response from Vaccine Strain Composition

The elicitation of broadly neutralizing antibodies (bnAbs) is a major goal of vaccine design for highly mutable pathogens, such as influenza, HIV, and coronavirus. Although many rational vaccine design strategies for eliciting bnAbs have been devised, their efficacies need to be evaluated in preclinical animal models and in clinical trials. To improve outcomes for such vaccines, it would be useful to develop methods that can predict vaccine efficacies against arbitrary pathogen variants. As a step in this direction, here, we describe a simple biologically motivated model of antibody reactivity elicited by nanoparticle-based vaccines using only antigen amino acid sequences, parametrized with a small sample of experimental antibody binding data from influenza or SARS-CoV-2 nanoparticle vaccinations. Results: The model is able to recapitulate the experimental data to within experimental uncertainty, is relatively insensitive to the choice of the parametrization/training set, and provides qualitative predictions about the antigenic epitopes exploited by the vaccine, which are testable by experiment. For the mosaic nanoparticle vaccines considered here, model results suggest indirectly that the sera obtained from vaccinated mice contain bnAbs, rather than simply different strain-specific Abs. Although the present model was motivated by nanoparticle vaccines, we also apply it to a mutlivalent mRNA flu vaccination study, and demonstrate good recapitulation of experimental results. This suggests that the model formalism is, in principle, sufficiently flexible to accommodate different vaccination strategies. Finally, we show how the model could be used to rank the efficacies of vaccines with different antigen compositions. Conclusion: Overall, this study suggests that simple models of vaccine efficacy parametrized with modest amounts of experimental data could be used to compare the effectiveness of designed vaccines.

The Role of Dendritic Cells in Adaptive Immune Response Induced by OVA/PDDA Nanoparticles

Background/Objective: Cationic polymers were shown to assemble with negatively charged proteins yielding nanoparticles (NPs). Poly-diallyl-dimethyl-ammonium chloride (PDDA) combined with ovalbumin (OVA) yielded a stable colloidal dispersion (OVA/PDDA-NPs) eliciting significant anti-OVA immune response. Dendritic cells (DCs), as sentinels of foreign antigens, exert a crucial role in the antigen-specific immune response. Here, we aimed to evaluate the involvement of DCs in the immune response induced by OVA/PDDA. Methods: In vivo experiments were used to assess the ability of OVA/PDDA-NPs to induce anti-OVA antibodies by ELISA, as well as plasma cells and memory B cells using flow cytometry. Additionally, DC migration to draining lymph nodes following OVA/PDDA-NP immunization was evaluated by flow cytometry. In vitro experiments using bone marrow-derived DCs (BM-DCs) were used to analyze the binding and uptake of OVA/PDDA-NPs, DC maturation status, and their antigen-presenting capacity. Results: Our data confirmed the potent effect of OVA/PDDA-NPs inducing anti-OVA IgG1 and IgG2a antibodies with increased CD19+CD138+ plasma cells and CD19+CD38+CD27+ memory cells in immunized mice. OVA/PDDA-NPs induced DC maturation and migration to draining lymph nodes. The in vitro results showed higher binding and the uptake of OVA/PDDA-NPs by BM-DCs. In addition, the NPs were able to induce the upregulation of costimulatory and MHC-II molecules on DCs, as well as TNF-α and IL-12 production. Higher OVA-specific T cell proliferation was promoted by BM-DCs incubated with OVA/PDDA-NPs. Conclusions: The data showed the central role of DCs in the induction of antigen-specific immune response by OVA-PDDA-NPs, thus proving that these NPs are a potent adjuvant for subunit vaccine design.

Animal Brucellosis in Egypt: Review on Evolution, Epidemiological Situation, Prevalent Brucella Strains, Genetic Diversity, and Assessment of Implemented National Control Measures

Brucellosis is a neglected zoonotic disease that has a significant economic and public health impact, especially in endemic countries. This review delves deeply into brucellosis’s current epidemiological situation and potential sources of livestock infection in Egypt during the last two decades. MLVA-16 and Whole Genome Sequencing based on core-genome SNP analyses confirm the presence of different B. abortus and B. melitensis outbreak strains, both older widely disseminated Brucella strains and newly introduced ones. Despite implementing the test-and-slaughter control strategy over forty years, the disease is still endemic, and different Brucella species circulate among several animal species. The raising of mixed animal species in the same households or farms, exposure to aborted animals, and lack of public awareness about brucellosis transmission are among the main risk factors for increasing livestock brucellosis prevalence in Egypt. Young animals’ voluntary vaccination, lack of a nationwide animal identification system, and uncontrolled animal movement stand beyond the ineffectively applied control strategy and may be subdued by applying mass vaccination to decrease disease prevalence dramatically and target imported camels, domestic pigs, and dogs (housed and stray) in the national control surveillance. Increasing awareness through educational campaigns is compulsory to reduce brucellosis transmission risk to livestock/humans.

Advancing veterinary vaccines design through trained immunity insights

Trained immunity, characterized by long-term functional reprogramming of innate immune cells, offers promising new directions for veterinary vaccine development. This perspective examines how trained immunity can be integrated into veterinary vaccine design through metabolic reprogramming and epigenetic modifications. We analyze key molecular mechanisms, including the shift to aerobic glycolysis and sustained epigenetic changes, that enable enhanced immune responses. Strategic approaches for vaccine optimization are proposed, focusing on selecting effective trained immunity inducers, developing innovative adjuvant systems, and achieving synergistic enhancement of immune responses. While implementation challenges exist, including individual response variations and safety considerations, trained immunity-based vaccines show potential for providing broader protection against emerging pathogens. This approach could revolutionize veterinary vaccinology by offering enhanced efficacy and cross-protection against heterologous infections, particularly valuable for zoonotic disease control.

Correction to: A proof of concept for neutralizing antibody-guided vaccine design against SARS-CoV-2

Correction to: A proof of concept for neutralizing antibody-guided vaccine design against SARS-CoV-2

Potential and development of cellular vesicle vaccines in cancer immunotherapy.

Cancer vaccines are promising as an effective means of stimulating the immune system to clear tumors as well as to establish immune surveillance. In this paper, we discuss the main platforms and current status of cancer vaccines and propose a new cancer vaccine platform, the cytosolic vesicle vaccine. This vaccine has a unique structure that can integrate antigen and adjuvant carriers to improve the delivery efficiency and immune activation ability, which brings new ideas for cancer vaccine design. Tumor exosomes carry antigens and MHC-peptide complexes, which can provide tumor antigens to antigen-processing cells and increase the chances of recognition of tumor antigens by immune cells. DEVs play a role in amplifying the immune response by acting as carriers for the dissemination of antigenic substances in dendritic cells. OMVs, with their natural adjuvant properties, are one of the advantages for the preparation of antitumor vaccines. This paper presents the advantages of these three bacteria/extracellular vesicles as cancer vaccines and discusses the potential applications of functionally modified extracellular vesicles as cancer vaccines after cellular engineering or genetic engineering, as well as current clinical trials of extracellular vesicle vaccines. In summary, extracellular vesicle vaccines are a promising direction for cancer vaccine research.

Immunoinformatics-guided design of a multiepitope peptide vaccine targeting the receptor-binding domain of SARS-CoV-2 spike glycoprotein: insights from Indonesian samples.

The emergence of new variants of SARS-CoV-2, including Alpha, Beta, Gamma, Delta, Omicron variants, and XBB sub-variants, contributes to the number of coronavirus cases worldwide. SARS-CoV-2 is a positive RNA virus with a genome of 29.9 kb that encodes four structural proteins: spike glycoprotein (S), envelope glycoprotein (E), membrane glycoprotein (M), and nucleocapsid glycoprotein (N). These proteins are vital for viral activity, with the S protein facilitating attachment and membrane fusion through the receptor-binding domain (RBD) located in the S1 subunit. The RBD recognizes and binds to the human angiotensin-converting enzyme 2 (ACE-2) protein. An immunoinformatic-aided design of a peptide-based multiepitope vaccine candidate targeting the RBD glycoprotein is constructed from the SARS-CoV-2 sequence data base from various regions of Indonesia (Jakarta, West Java, and Bali). The results show that the RBD region of with accession ID EPI_ISL_15982641 from West Java had the highest antigenicity of 0.5904. This isolate is non-toxic and non-allergenic and shows a total of 18 LBL epitopes, 72 CTL epitopes, and 98 HTL epitopes. The epitope that has the best overall binding affinity was GCHNKCAY for MHC-I and GGCVFSYVGCHNKCAYWV for MHC-II which show a binding affinity of -13.6 and -15.5 (kcal/mol), respectively. Therefore, this study aims to design an epitope vaccine candidate based on samples from Indonesia that has good characteristics and may have the potential to stimulate an immune response against SARS-CoV-2.

Live Plague Vaccine Development: Past, Present, and Future

During the last 100 years, vaccine development has evolved from an empirical approach to one of the more rational vaccine designs where the careful selection of antigens and adjuvants is key to the desired efficacy for challenging pathogens and/or challenging populations. To improve immunogenicity while maintaining a favorable reactogenicity and safety profile, modern vaccine design must consider factors beyond the choice of target antigen alone. With new vaccine technologies currently emerging, it will be possible to custom-design vaccines for optimal efficacy in groups of people with different responses to vaccination. It should be noted that after a fairly long period of overwhelming dominance of papers devoted to subunit plague vaccines, materials devoted to the development of live plague vaccines have increasingly been published. In this review, we present our opinion on reasonable tactics for the development and application of live, safe, and protective human plague vaccines causing an enhanced duration of protection and breadth of action against various virulent strains in vaccination studies representing different ages, genders, and nucleotide polymorphisms of the genes responsible for immune response.

MRNA vaccines with RBD mutations have broad-spectrum activity against SARS-CoV-2 variants in mice

The emergence of SARS-CoV-2 variants with defined mutations that enhance pathogenicity or facilitate immune evasion has resulted in a continual decline in the protective efficacy of existing vaccines. Therefore, there is a pressing need for a vaccine capable of combating future variants. In this study, we designed new mRNA vaccines, BSCoV05 and BSCoV06, and generated point mutations in the receptor-binding domain (RBD) of the original Wuhan strain to increase their broad-spectrum antiviral activity. Additionally, we used the BA.1 RBD as a control. Both vaccines elicited a robust immune response in BALB/c and K18-hACE2 mice, generating high levels of specific binding antibodies against the BA.2 RBD. Moreover, all three vaccines induced neutralizing antibodies against the prototype viral strain and relevant variants, including the Alpha and Beta strains and the Omicron variants BA.1, BA.2, BA.5, XBB.1.5, XBB.1.16, EG.5.1, and EG.5.1.1, with BSCoV06 demonstrating broader neutralizing antibody activity. Both BSCoV05 and BSCoV06 also elicited a cellular immune response. After the challenge, both BSCoV05 and BSCOV06 provided protection against the EG.5.1 strain in both mouse strains. Therefore, these two vaccines merit further evaluation in nonhuman primates, and this vaccine design strategy should be explored for its potential application in combating future SARS-CoV-2 variants, offering valuable insights into broad-spectrum vaccine development.

Spatiotemporal Dynamic Immunomodulation by Infection-Mimicking Gels Enhances Broad and Durable Protective Immunity Against Heterologous Viruses.

Despite their safety and widespread use, conventional protein antigen-based subunit vaccines face significant challenges such as low immunogenicity, insufficient long-term immunity, poor CD8+ T-cell activation, and poor adaptation to viral variants. To address these issues, an infection-mimicking gel (IM-Gel) is developed that is designed to emulate the spatiotemporal dynamics of immune stimulation in acute viral infections through in situ supramolecular self-assembly of nanoparticulate-TLR7/8a (NP-TLR7/8a) and an antigen with tannic acid (TA). Through collagen-binding properties of TA, the IM-Gel enables sustained delivery and enhanced retention of NP-TLR7/8a and protein antigen in the lymph node subcapsular sinus of mice for over 7 days, prolonging the exposure of vaccine components in both B cell and T cell zones, leading to robust humoral and cellular responses. The IM-Gel system with the influenza A antigen confers cross-protection against multiple influenza subtypes (H1N1, H5N2, H3N2, H7N3, and H9N2) with long-term immune responses. Combination of the IM-Gel with the SARS-CoV-2 spike protein also elicits strong cross-reactive antibody responses against multiple SARS-CoV-2 variants (Alpha, Beta, NY510+D614G, Gamma, Kappa, and Delta). The IM-Gel, as a programmable immunomodulatory material, provides a vaccine design principle for the development of next-generation universal vaccines that can elicit broad and durable protective immunity against emerging viruses.

Structural and Functional Glycosylation of the Abdala COVID-19 Vaccine.

Abdala is a COVID-19 vaccine produced in Pichia pastoris and is based on the receptor-binding domain (RBD) of the SARS-CoV-2 spike. Abdala is currently approved for use in multiple countries with clinical trials confirming its safety and efficacy in preventing severe illness and death. Although P. pastoris is used as an expression system for protein-based vaccines, yeast glycosylation remains largely uncharacterised across immunogens. Here, we characterise N-glycan structures and their site of attachment on Abdala and show how yeast-specific glycosylation decreases binding to the ACE2 receptor and a receptor-binding motif (RBM) targeting antibody compared to the equivalent mammalian-derived RBD. Reduced receptor and antibody binding is attributed to changes in conformational dynamics resulting from N-glycosylation. These data highlight the critical importance of glycosylation in vaccine design and demonstrate how individual glycans can influence host interactions and immune recognition via protein structural dynamics.

Structural determinants of peanut induced anaphylaxis.

Human monoclonal IgE antibodies recognizing peanut allergens have recently become available, but we lack a detailed understanding of how these IgEs target allergens. To determine the molecular details of the antibody-allergen interaction for a panel of clinically important human IgE monoclonal antibodies and to develop strategies to disrupt disease causing antibody-allergen interactions. We identified candidates from a panel of epitope binned human IgE monoclonals that recognize two important and homologous peanut allergens, Ara h 2 and Ara h 6. Crystal structures were determined revealing the interfaces (antigenic sites) of exemplars of five common IgE bins. Among the common antigenic sites on Ara h 2 and Ara h 6, two sites (A and B) are highly conserved between the allergens, explaining the cross reactivity of antibodies that recognize these sites. Three sites (C, D, and F) involve residues that are not conserved between the allergens. Of the five common sites, three Sites (B, C, and D) involve residues that are only near each other when the allergens are properly folded, such that these sites are conformational. Two additional sites (sites A and F) involve largely linear stretches of amino acids. Site F targeted antibody, 38B7, binds to a peptide sequence DPYSPOHS, in which hydroxylation of the last proline is critical for binding. This sequence is repeated two or three times depending on the Ara h 2 isoform, enabling 38B7 to induce anaphylaxis as a single monoclonal, without a second antibody. We have mutated key residues in each site and created a panel of hypoallergens, having reduced IgE mAb binding and lacking the ability to induce anaphylaxis in our murine model. We created a structural map of the IgE antibody response to the most important peanut allergen proteins to enable the design of new allergy immunotherapies and vaccines.

Antitumor mRNA vaccines based on neoantigens

Objective: to summarize the available data on clinical trials of vaccines based on mRNA encoding neoantigens. Material and Methods. Data were searched on https://classic.clinicaltrials.gov and https://pubmed.ncbi.nlm.nih.gov/, from January 2013 to May 2024 using the keywords “neoantigen” and “vaccine”, and the information on mRNA-based drugs was then selected. Of the 148 studies retrieved, 54 were selected to write a systematic review. Results. A bibliometric analysis of data in the field of therapeutic cancer vaccines from 2013 to 2024 showed that the majority of studies focused on mRNA vaccines encoding neoantigens. this paper presents a brief description of the mRNA platform and provides an overview of clinical trials of anticancer mRNA vaccines from 2013 to 2024. Preparations of leading biotech firms in Europe and the USA involved in the development of anticancer mRNA vaccines, such as Cevumeran (BioNTech), mRNA-4157/V940 (Moderna), as well as vaccines from companies in the PRC - Stemirna Therapeutics, NeoCura, Hangzhou Neoantigen Therapeutics, etc. - are reviewed. Conclusion. The use of vaccine technology based on mRNAs encoding tumor neoantigens can significantly increase the potential of antitumor immunotherapy.

All-positive HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb in a patient with hepatitis B: A case report.

Mass vaccination, low cost of immunoglobulins, and new drugs led to the emergence of new, unusual patterns of hepatitis B serum markers. This study reported a rare case of hepatitis B with all 5 positive serum markers, including HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb. A 30-year-old female patient was admitted due to abnormal liver function. The 5 serum markers were all positive (+), including HBsAg, HBsAb, HBeAg, HBeAb, and HBcAb. After antiviral therapy, she was discharged with normal liver function and decreased hepatitis B virus-DNA levels, but all 5 serum markers were still positive. Regular follow-up was conducted every 3 months. Abnormal liver function. The patient received antiviral treatment and liver protection therapy using entecavir dispersive tablet 0.5 mg po qd and glycyrrhizate diamine enteric capsule 150 mg po tid. The patient's liver function was normal, hepatitis B virus-DNA continued to decline, and HBeAb turned negative at 6 months. After 9 and 12 months of follow-up, the results of hepatitis B markers in the patient were stable in HBsAg positive (+), HBeAb positive (+), and HBcAb positive (+). The rare pattern of all 5 positive hepatitis B markers may occur in patients with chronic hepatitis B. Improvements can be achieved using first-line drugs and conventional treatment. Nevertheless, more attention should be paid to the patient's condition.

Altering the intracellular trafficking of Necator americanus GST-1 antigen yields novel hookworm mRNA vaccine candidates.

The antigen Na-GST-1, expressed by the hookworm Necator americanus, plays crucial biochemical roles in parasite survival. This study explores the development of mRNA vaccine candidates based on Na-GST-1, building on the success of recombinant Na-GST-1 (rNa-GST-1) protein, currently assessed as a subunit vaccine candidate, which has shown promise in preclinical and clinical studies. By leveraging the flexible design of RNA vaccines and protein intracellular trafficking signal sequences, we developed three variants of Na-GST-1 as native (cytosolic), secretory, and plasma membrane-anchored (PM) antigens. After one immunization in mice, mRNA vaccines induced an earlier onset of antigen-specific antibodies compared to rNa-GST-1. Following two immunizations, mRNA vaccines induced similar or superior levels of antigen-specific antibodies compared to rNa-GST-1. Secretory Na-GST-1 was comparable to rNa-GST1 in producing neutralizing antibodies against Na-GST-1's thiol transferase activity, while native Na-GST-1 induced a more robust CD8+ T cell response due to its intracellular accumulation. Although PM Na-GST-1 elicited one of highest titers of antigen-specific antibody and a diverse set of memory T-cell populations, it resulted in a lower ratio of neutralizing antibodies after IgG purification compared to the other vaccine candidates. These findings emphasize the importance of antigen localization in tailoring immune responses and suggest that extracellular antigens are more effective for inducing humoral responses, whereas cytosolic antigen accumulation enhances MHC-1 peptide presentation. Future studies will determine if these in vitro and immunogenicity findings translate to in vivo efficacy. Altogether, mRNA vaccines offer numerous possibilities in the development of multivalent vaccines with single or multiple antigens.

Advanced Polymeric Nanoparticles for Cancer Immunotherapy: Materials Engineering, Immunotherapeutic Mechanism and Clinical Translation.

Cancer immunotherapy, which leverages immune system components to treat malignancies, has emerged as a cornerstone of contemporary therapeutic strategies. Yet, critical concerns about the efficacy and safety of cancer immunotherapies remain formidable. Nanotechnology, especially polymeric nanoparticles (PNPs), offers unparalleled flexibility in manipulation-from the chemical composition and physical properties to the precision control of nanoassemblies. PNPs provide an optimal platform to amplify the potency and minimize systematic toxicity in a broad spectrum of immunotherapeutic modalities. In this comprehensive review, the basics of polymer chemistry, and state-of-the-art designs of PNPs from a physicochemical standpoint for cancer immunotherapy, encompassing therapeutic cancer vaccines, in situ vaccination, adoptive T-cell therapies, tumor-infiltrating immune cell-targeted therapies, therapeutic antibodies, and cytokine therapies are delineated. Each immunotherapy necessitates distinctively tailored design strategies in polymeric nanoplatforms. The extensive applications of PNPs, and investigation of their mechanisms of action for enhanced efficacy are particularly focused on. The safety profiles of PNPs and clinical research progress are discussed. Additionally, forthcoming developments and emergent trends of polymeric nano-immunotherapeutics poised to transform cancer treatment paradigms into clinics are explored.

Long, Synthetic Staphylococcus aureus Type 8 Capsular Oligosaccharides Reveal Structural Epitopes for Effective Immune Recognition.

Staphylococcus aureus is a Gram-positive bacterium that is responsible for severe nosocomial infections. The rise of multidrug-resistant strains, which can pose significant health threats, prompts the development of new treatment interventions, and much attention has been directed at the development of prophylactic and therapeutic vaccination strategies. Capsular polysaccharides (CPs) are key protective elements of the S. aureus cell wall and have been proposed as promising candidate antigens. Thirteen different CP serotypes have been identified to date, of which types 5 and 8 are the most prominent. CP8 is composed of trisaccharide repeating units that are built up from an N-acetyl-4-O-acetyl-β-d-mannosaminuronic acid, that carries a C-4-O-acetyl, an N-acetyl-α-d-fucosamine, and an N-acetyl-α-l-fucosamine. Synthetic oligosaccharides are valuable tools to unravel the immunogenicity of bacterial oligosaccharides at the molecular level. However, the rare monosaccharides, cis-glycosidic linkages, and O-acetylation represent significant challenges for the synthesis of CP8 fragments. Here the stereoselective assembly of well-defined CP8 fragments, comprising a trimer, hexamer, nonamer, and dodecamer, is presented. This is the first time that fragments larger than a single repeating trisaccharide, which has been proven to be insufficient for antigenic activity, have been assembled. Structural studies have revealed a linear conformation for the oligosaccharides, with each trisaccharide repeat tilted ∼90° with respect to the flanking repeats, which is stabilized by the acetyl groups that prevent rotation around the glycosidic linkages. The N-acetyl groups in each repeating unit point in the same direction, generating a hydrophobic flank in the trisaccharide repeats. We applied the oligomers to generate model glycoconjugate vaccine modalities, which we then used to raise anti-CP8 antibodies. The antibody interaction and immunization studies have revealed a clear length dependent structure-activity relationship for the oligosaccharides, with an oligosaccharide of at least three repeating units required for an adequate immune response.