Search Results (1,795)

Background/Objectives: Respiratory pathogens such as influenza virus and SARS-CoV-2 pose major threats to global public health. Current vaccines provide limited mucosal protection against respiratory infection, while vaccine-induced immunity can wane over time. Intranasal vaccination has emerged as a promising approach to induce mucosal immunity, however relatively low immunogenicity and limited durability remain major challenges. Various strategies have therefore been explored to improve intranasal vaccine efficacy, including mucosal adjuvants and alternative vaccine platforms. In this study, we evaluated the magnitude and durability of systemic and mucosal immune responses induced by an adenoviral vector vaccine. Methods: Six-week-old female C57BL/6 mice were immunized intranasally or intramuscularly with a single dose of an adenoviral vector vaccine and compared with mice receiving one or two doses of an intranasal CpG-adjuvanted protein vaccine. Humoral immune responses in serum and BALF, as well as cellular immune responses in the mLNs, lungs, and blood, were evaluated. We further assessed Ova-specific CD8 T cells with a lung-resident phenotype by class I MHC-peptide tetramer staining combined with intravascular labeling, allowing their direct ex vivo identification. Results: A single dose of intranasal adenoviral vector vaccination elicited potent serum IgG and BALF IgA responses, together with antigen-specific CD8 T cell responses in the blood, mLNs, and lungs. Notably, these systemic and respiratory mucosal immune responses were sustained for up to 4 months after vaccination, with lung-resident CD8 T cell responses detected at this time point. In contrast, intramuscular adenoviral vector vaccination predominantly induced systemic immunity. Intranasal CpG-adjuvanted protein vaccination induced weaker responses after a single dose, while booster vaccination enhanced systemic antibody and cellular responses but showed limited induction of mucosal immunity. Conclusions: A single intranasal dose of Ad5-Ova induced systemic and respiratory mucosal immune responses comparable to those observed after two-dose Ova+CpG vaccination, while maintaining these responses for up to 4 months. These findings suggest adenoviral vectors as a promising platform for inducing long-lasting respiratory mucosal immunity. Full article

Hantaan virus (HTNV) is the predominant causative agent of hemorrhagic fever with renal syndrome (HFRS) in China, yet no specific antiviral therapy is currently available. Neutralizing antibodies (NAbs) represent a promising strategy, but most existing anti-HTNV NAbs are heterologous and carry immunogenicity risks. Here, two fully human antibodies from a previously established human anti-HTNV phage display library were generated and characterized. KJJ3, a VL-VL tandem antibody derived from clone 3–12, showed weak binding to inactivated HTNV and minimal neutralizing activity (IC₅₀ = 27.12 μg/mL). However, KJJ4, an engineered IgG4 antibody derived from clone 4–19 and carrying the S108P hinge mutation to prevent Fab-arm exchange, bound inactivated HTNV antigen and recombinant glycoprotein Gn (residues 19–371) in a dose-dependent manner, with only weak binding to Gc. Surface plasmon resonance yielded an association rate constant of 4.70 × 10³ M⁻¹s⁻¹, a dissociation rate constant of 3.06 × 10⁻³ s⁻¹, and an equilibrium dissociation constant of 650 nM for monomeric Gn_19–371. In a Vero E6 focus-reduction microneutralization assay, KJJ4 neutralized HTNV in vitro with an IC₅₀ of 2.879 μg/mL. These data establish KJJ4 as a fully human anti-HTNV antibody with experimentally defined in vitro binding and neutralizing activity, warranting further evaluation in animal models of HTNV infection. Full article

Lyme borreliosis (LB) is a tick-borne disease caused by a diverse and expanding group of spirochetes characterized by complex biology and advanced immune evasion mechanisms. It presents a wide range of clinical symptoms affecting multiple organ systems and can lead to persistent complications. The pathogenesis of LB remains incompletely understood, and diagnosis typically relies on serologic assays to detect antibodies against LB. However, the standard two-tiered testing (STTT) algorithm is limited by cross-reactivity, low sensitivity, and delayed results, hindering timely and accurate diagnosis. Although molecular tests are considered the gold standard, their reliance on centralized laboratories can delay critical treatment decisions. This underscores the urgent need for rapid, reliable diagnostic tools, particularly for use at the point of hospital admission. Point-of-care serological and direct antigen testing can provide actionable information, supporting decentralized healthcare systems in diagnosing complex diseases, such as LB. In this study, we developed two fluorescent polarization immunoassays (FPIAs) using IgM and IgG LB-specific synthetic epitopes/peptides to evaluate their diagnostic potential. These FPIAs showed high sensitivity and specificity in detecting IgM or IgG anti-LB antibodies in patient sera within minutes. The fluorescently labeled synthetic peptides produced significant polarization differences between infected and healthy samples, allowing clear discrimination. The FPIA-LB functions as a one-step assay, eliminating the need for secondary antibodies or complex protocols. This work highlights the FPIA technique as a robust, rapid, and efficient tool for LB diagnosis, offering a promising advance in improving early detection and patient outcomes, which could save lives and reduce long-term health complications. Full article

Highly pathogenic avian influenza (HPAI) represents an enormous pandemic risk amid the ongoing H5N1 panzootic. HPAI, defined by its high lethality in domestic poultry, includes the influenza A virus (IAV) H5N1 and H7N9 subtypes and has a 40–50% case fatality rate in humans. To facilitate the development of efficacious HPAI vaccination regimens and isolation of HPAI-neutralizing monoclonal antibodies (nmAbs) for prophylactic and therapeutic use, we performed a proof-of-concept pilot study wherein we developed an array of mRNA and adenovirus-vectored vaccines encoding HPAI hemagglutinins (HAs) and then assessed their immunogenicity in IAV-naïve Indian rhesus macaques (RMs). All RMs developed binding IgG recognizing both HPAI HAs. HPAI-nAbs were detected in RMs vaccinated with full-length HAs, but not in RMs vaccinated with HA stems alone. Potent HPAI neutralization activity was observed in two animals with serum ID₅₀ titers of ~1:100,000 against H5N1 and ~1:50,000 against H7N9. Most RMs developed cross-reactive IgG recognizing the HAs of additional IAV subtypes, and HA-specific B cells were readily identifiable in vaccinee PBMCs by flow cytometric analysis. The results of our pilot study suggest that elicitation of potent HPAI-nAb responses is enhanced by vaccination with the HA head domain and that vaccination with the HA stem alone tends to elicit binding non-nAbs. Furthermore, use of our fluorophore-conjugated HA probes to identify HA-specific B cells could enable HPAI-nmAb isolation. Collectively, our findings could facilitate the development of novel vaccines and nmAb therapeutics leveraging the superior neutralization potency of HA head-specific Abs to prevent and treat HPAI infections in humans. Full article

Background: Aluminum-adjuvanted hepatitis B vaccines effectively prevent primary HBV infection but predominantly favor humoral immunity and have limited capacity to induce strong cellular responses. To improve immune-response quality, we developed a Ganoderma lucidum polysaccharide-modified hybrid nanoparticle adjuvant (GHNP) for hepatitis B surface antigen (HBsAg) vaccination. Methods: Cationic PEG-PCL/DOTAP hybrid nanoparticles (HNPs) were surface-modified with Ganoderma lucidum polysaccharide (GLP) at different mass ratios and characterized by particle size, polydispersity index, zeta potential, and transmission electron microscopy. Antigen uptake, RAW264.7 cell viability, MHC II expression, and TLR2/4-associated TNF-α secretion were evaluated in vitro. C57BL/6 mice were immunized intramuscularly with PBS, HBsAg, HBsAg + Aluminum, HBsAg@HNP, or HBsAg@GHNP6 on Days 0, 14, and 28. HBsAg-specific antibodies, splenocyte activation, proliferation, and cytokine secretion were assessed. Results: GHNP6 showed suitable physicochemical properties, acceptable cytocompatibility at concentrations up to 10 μg·mL⁻¹, and efficient model-antigen uptake. GHNP increased MHC II expression in RAW264.7 cells, and TLR2/4 inhibition reduced nanoparticle-associated TNF-α secretion, supporting involvement of these pathways in immune activation. In vivo, HBsAg@GHNP6 induced robust HBsAg-specific IgG responses and a higher IgG2a/IgG1 ratio than HBsAg@HNP and HBsAg + Aluminum. It also produced the highest splenocyte proliferation after HBsAg restimulation, with lower IL-6 secretion than HBsAg + Aluminum and moderately increased IFN-γ compared with PBS and free HBsAg. Conclusions: GHNP integrates nanoparticle-assisted antigen delivery with GLP-mediated immunomodulation and represents a promising strategy for enhancing cellular immune responses while maintaining humoral immunity in HBsAg vaccination. Full article

Rabbit monoclonal antibodies (RabMAbs) are valuable for biomedical research and diagnostic applications because of their high affinity, specificity, and broad epitope recognition; here, we established an integrated phenotype-linked workflow for rapid RabMAb discovery using serum-derived polyclonal mouse IgG as a proof-of-concept model antigen. Three Big-Eared White rabbits were immunized in parallel, and the rabbit exhibiting the highest serum endpoint titer was selected for the complete downstream single-B-cell discovery workflow. Approximately 5 × 10⁵ activated B cells were subjected to polydisperse oblate dispersion system (POD)-based screening, yielding 13,266 antigen-positive POD events. Following recovery and 10× Genomics single-cell V(D)J sequencing, 4294 B-cell barcodes yielded valid/interpretable V(D)J data, of which 2099 contained at least one complete, productive, and translatable heavy-chain/light-chain pair, generating 2199 functional VH/VL pairing records. AbFinder™-assisted prioritization generated a computationally recommended pool of 158 candidates, and the five highest-ranked VH/VL pairs within this pool were selected for recombinant expression and validation. All five yielded antigen-reactive RabMAbs with an endpoint ELISA titer of 1:256,000 and BLI-derived apparent K_D values ranging from 4.19 × 10⁻¹⁰ to 9.79 × 10⁻⁹ M. The antibodies showed differential concentration-dependent reactivity toward mouse IgG1, IgG2a, IgG2b, and IgG3 preparations, weak reactivity toward human IgG, and clone-dependent reactivity toward rat IgG. The workflow from spleen collection to functional validation was completed within approximately three weeks. Because only five prioritized candidates from one selected responder rabbit were evaluated, the 5/5 validation outcome should not be interpreted as an overall platform hit rate or definitive validation of the prioritization algorithm. These findings support the feasibility of this workflow for research-grade and diagnostic antibody discovery, while broader evaluation will require larger candidate cohorts, independent biological validation, and additional antigen classes. Full article

Background: Measles, mumps, and rubella outbreaks continue to occur despite high vaccination coverage, raising concerns about long-term vaccine-induced immunity. This study assessed serological protection against measles, mumps, rubella, and varicella in fully vaccinated Russian adolescents to identify immunity gaps and inform revaccination strategies. Methods: Serum IgG was quantified by commercial ELISA. Analytical cut-offs were: measles ≥ 0.18 IU/mL, rubella ≥ 30 IU/mL, mumps index ≥ 1.0 (index = OD/0.467), and varicella ≥ 1.0 IU/mL; equivocal results were classified as negative in the primary analysis and as positive in a sensitivity analysis. Geometric mean concentrations (GMC) were computed on the natural-logarithm scale. Results: Seropositivity differed markedly between infections (χ² 55.1; p < 0.001): rubella 81.4% (95% CI 74.6–86.7), varicella 57.7% (95% CI 49.8–65.2), mumps 53.2% (95% CI 45.4–60.9) and measles 41.0% (95% CI 33.6–48.9). GMC was lowest for measles (0.132; 95% CI 0.111–0.158) and highest for rubella (61.9; 95% CI 55.3–69.2). The measles estimate was sensitive to the treatment of equivocal results, rising to 53.2% (95% CI 45.4–60.9) at the manufacturer’s cut-off of ≥0.12 IU/mL; rubella rose to 94.9% at ≥16 IU/mL. Conclusions: Lower seropositivity rates for measles and mumps were identified among fully vaccinated adolescents, which fall below standard epidemiological benchmarks. In contrast, rubella seropositivity was robust at 81.4%. Because the measles estimate depended strongly on the assay cut-off applied, and because enzyme immunoassays are known to underestimate seroprevalence relative to neutralization testing, these findings describe the distribution of circulating antibody rather than the prevalence of susceptibility and warrant confirmation in larger representative samples with neutralization testing. Full article

Background/Objectives: Antiphospholipid antibodies (aPL) comprise anticardiolipin antibodies (aCL), antibodies against β2 glycoprotein I (anti-β2GPI) and lupus anticoagulant (LA). LA is an established risk factor for thrombosis and pregnancy morbidity in the general population. In people with type 1 diabetes (T1D), aPL have been proposed as potential predictors of microvascular and macrovascular diabetes-related complications. The aim of the present prospective, observational study was to investigate the prevalence of aPL in a well-defined cohort of adults presenting with uncomplicated T1D compared with healthy controls. In addition, we prospectively examined whether aPL titers or positivity were potentially associated with the subsequent development of diabetes-related complications. Methods: Two hundred (200) adults with T1D and without microvascular or macrovascular complications participated (mean age, 37.9 ± 10.6 years; mean diabetes duration, 21.00 ± 9.20 years). We also included 200 age- and sex-matched healthy controls (mean age, 37.7 ± 10.1 years) without diabetes mellitus or other autoimmune diseases. The aPL panel, including aCL ΙgG/IgM, anti- β2GPI IgG/IgM, and LA, was assessed using standardized laboratory methods. Participants with T1D were re-evaluated after a mean follow-up of 7.6 years. Results: Titers of aCL IgG/IgM and anti-β2GPI IgG, as well as positivity of aCL-IgG and aCL-IgM, were higher in participants with T1D compared with healthy controls, whereas LA positivity was very low in both groups. In the T1D group, aCL-IgG titers significantly correlated with age and diabetes duration. Neither aCL-IgG titers nor positivity was associated with the development of microvascular or macrovascular complications or with all-cause mortality during follow-up. Conclusions: In adults with long-standing, uncomplicated T1D, most aPL titers and positivity rates were higher than those observed in healthy controls. However, aCL-IgG titers and positivity were not associated with the subsequent development of diabetes-related complications. Larger prospective studies are required to determine whether aPL have predictive value for diabetes-related complications and to identify subgroups of people with T1D who may benefit from aPL testing. Full article

Ophelia syndrome is a rare paraneoplastic limbic encephalitis associated with classical Hodgkin lymphoma (cHL), most often with antibodies against metabotropic glutamate receptor 5 (mGluR5). We describe a 19-year-old man with newly diagnosed cHL who presented with generalised seizures, cognitive dysfunction, spastic paraparesis, cauda equina-related autonomic dysfunction, and a 35 × 31 mm haemorrhagic inflammatory lesion in the right temporal lobe. Brain biopsy showed dense intravascular and perivascular inflammatory infiltrates without neoplastic cells. Cerebrospinal fluid demonstrated pleocytosis and intrathecal IgG synthesis with type III oligoclonal bands. Serum and cerebrospinal fluid neuronal autoantibody panels were negative, but mGluR5 antibodies were not assessed. Cervical lymph node biopsy confirmed nodular sclerosis cHL, stage IIA. After exclusion of infectious encephalitis and central nervous system lymphoma, the presentation was considered most consistent with Ophelia-like paraneoplastic limbic encephalitis. ABVD chemotherapy was initiated, with rapid neurological improvement after the first cycle. Complete metabolic response was achieved after two cycles and sustained after six cycles. At 15-month follow-up, major neurological symptoms had not recurred, although bladder and bowel dysfunction persisted. This case highlights the importance of considering paraneoplastic limbic encephalitis in cHL despite negative standard neuronal antibody testing and of documenting whether mGluR5 antibodies were assessed. Full article

Background/Objectives: Maternal antibodies can inhibit vaccine-specific humoral responses in early life, leaving infants at increased risk for severe disease for vaccine-preventable infections. In the case of SARS-CoV-2, infants under the age of 3 months represented most child hospitalizations, yet there is no approved vaccine for children under the age of 6 months. There is a clear need for effective immunization in early life to prevent infant morbidity and mortality. Here, we established a mouse model to define how maternally derived antibodies shape early-life responses to mRNA vaccination. Methods: Adult female mice were immunized with PBS or 5 mcg of the SARS-CoV-2 mRNA-1273 vaccine via intramuscular injection and paired with a male. Pups from subsequent litters were immunized with PBS or 5 mcg of mRNA-1273 vaccine via intramuscular injection. Peripheral blood and spleens were collected at time points post-immunization. We measured vaccine-elicited anti-Spike IgG in mouse pups exposed or unexposed to vaccine-specific maternal IgG. Results: Spike-specific maternal IgG is detectable at high levels immediately after pup immunization or mock immunization; however, in mock immunized pups, it wanes by three weeks post-pup immunization. Pups born to immunized dams developed Spike specific IgG comparable to pups born to naïve dams. IgG subclass analyses distinguished passively acquired antibodies from vaccine-induced responses. Despite robust binding antibody responses, neutralizing activity against D614G pseudovirus was heterogeneous and did not scale proportionally with IgG titers, showing qualitative differences in early-life humoral immunity. Splenic Spike-specific B cell frequencies and T follicular helper (Tfh) cell responses were detectable in vaccinated pups irrespective of maternal immunization status, with Tfh cell frequencies peaking at day 7 post-immunization in both groups. Conclusions: Using SARS-CoV-2 as a model pathogen, we found that early-life mRNA vaccination can elicit humoral immune responses in the presence of maternal antibodies. Furthermore, the presence of maternal antibody did not inhibit the development of antigen-specific B cells or Tfh cells in the spleen. Our findings support the potential of extending vaccination strategies into early infancy and provide a framework for optimizing mRNA-based vaccine timing and design in the context of maternal immunity. Full article

Background: Vitamin D plays an important immunomodulatory role, and vitamin D deficiency has been associated with an increased risk of infections and autoimmune disorders. Although patients with some primary immunodeficiency disorders (PID) exhibit higher rates of vitamin deficiency, there are currently no evidence-based recommendations regarding whether children with PIDs require higher vitamin D supplementation than healthy peers. This study aimed to evaluate the nutritional status of vitamin D and vitamin D supplementation in children with PIDs. Methods: The study included 132 children diagnosed with PIDs according to the 2024 update of the phenotypic classification by the International Union of Immunological Societies (IUIS). The following variables were evaluated: body mass index (BMI), 25-hydroxyvitamin D (25(OH)D), calcium, phosphorus, immunoglobulins G, A and M, and number of neutrophils and lymphocytes in the blood. Results: Vitamin D deficiency occurred in 13% of all tested children, and in 22 and 33% of children with predominantly antibody deficiencies and complement deficiencies, respectively, with the median vitamin D supplementation of 1000 IU. The median serum 25(OH)D concentration was 30.75 ng/mL (32.7 ng/mL in girls and 30 ng/mL in boys). The multiple linear regression model showed that the concentration of serum phosphorus level (b = 0.312; p = 0.0497) and immunoglobulin G level (b = 0.433; p = 0.0009) had the greatest influence on the concentration of 25(OH)D. No statistically significant differences in 25(OH)D concentrations were observed among the different IUIS diagnostic groups or between children with normal and low IgG levels. Conclusions: In this retrospective cross-sectional study, children reportedly receiving median 1000 IU supplementation had median 25(OH)D of 30.75 ng/mL with 13% deficiency prevalence; however, causal attribution requires prospective evaluation. Full article

Studying protein structure dynamics is key to understanding protein function modulation. Alternative protein conformations are well discriminated from each other by nanoESI mass spectrometry and ion mobility measurements. Experimentally determined collisional cross-sections were compared to calculated collisional cross-sections of fifteen peptides, single-domain proteins, and protein complexes. The multi-domain proteins investigated here, four immunoglobulin G (IgG) antibodies and protein G, are present as compacted/folded “native” conformations in neutral buffered solutions, and they are identified by molecular ions with narrow charge-state distributions, relatively few charges, and small collisional cross-sections. Simultaneously present extended/folded but nevertheless “native” conformations produced additional ions with higher charge states, different charge-state distributions, and larger collisional cross-sections. Computed collisional cross-sections from compacted “o-shape” and extended “l-shape” protein G three-dimensional (3D) structures match experimental data, indicating equilibrium, and suggest a dynamic “o2l” flip process. Likewise, “m-shape” (compacted) and “Y-shape” (extended) IgGs are regarded as two supposedly reversibly adopted antibody conformations which may interchange by an “m2Y” flip. Adopting an m-shape would prevent an antibody-based initiation of humoral and cellular immune system responses, such as opsonophagocytosis, prior to antigen contact, which stands in line with the rearrangement hypothesis. Full article

Background/Objectives: Therapeutic antibodies have become an important modality for cancer treatment; however, effective targeted antibody therapies for T-cell acute lymphoblastic leukemia (T-ALL) remain limited. CD99 is a promising therapeutic target due to its high expression in leukemic T cells and its capacity to transmit apoptotic signals. However, the efficacy of antibody-mediated apoptosis may depend on the CD99 region recognized by the antibody. This study compared the in vitro apoptotic activity of two chimeric anti-CD99 antibodies, ChAbMT99/1 and ChAbMT99/3, which recognize distinct regions of CD99 in T-ALL models. Methods: ChAbMT99/1 and ChAbMT99/3 were generated as human IgG1 antibodies. Antibody reactivity and binding site specificity were characterized using peptide-based ELISA. Binding to native CD99, apoptosis induction in two-dimensional (2D) Jurkat E6.1 and MOLT-4 suspension cultures and three-dimensional (3D) Jurkat E6.1-derived spheroid models, and cytotoxic effects on peripheral blood mononuclear cells (PBMCs) were assessed by flow cytometry. In vitro hematologic effects were assessed using hemagglutination and platelet aggregation assays. Results: ChAbMT99/1 and ChAbMT99/3 specifically recognized peptides corresponding to distinct CD99 regions, with peptide-binding EC₅₀ values of 0.813 and 0.819 μg/mL, respectively. Both antibodies exhibited binding reactivity to native CD99 on the tested cells. Functionally, both antibodies induced Annexin V/7-AAD-defined cell death in both 2D and 3D T-ALL models compared with controls in a crosslinking-dependent manner. In contrast, both antibodies induced low levels of cell death (<10%) in bulk PBMCs, with no visible hemagglutination or platelet aggregation observed in samples from five selected donors under the stated assay conditions. Conclusions: Both chimeric anti-CD99 antibodies demonstrated in vitro apoptotic activity against T-ALL models despite recognizing distinct regions of CD99. These findings provide a rationale for further investigation of their other mechanisms of action to support the future development of CD99-targeted antibody therapy for T-ALL. Full article

Strongyloidiasis is a neglected, potentially lifelong disease caused by Strongyloides stercoralis that can lead to a high mortality rate in immunocompromised hosts; therefore, it is necessary to increase the accuracy of infection diagnosis. In the current study, we used Wistar rats experimentally infected with different burdens of Strongyloides venezuelensis to characterize circulating leukocytes and IgM, IgG, IgG1, IgG2a, and IgA reactivity before and after anthelmintic treatment or immunosuppression. Infection, especially with 500 L3, induced an increase in circulating leukocytes, particularly during the acute phase. Animals treated with ivermectin showed complete elimination of the parasite and an early reduction in circulating eosinophils. The production of IgM, IgG, and IgG1 anti-L3 (infective larvae) and anti-Sv (adult worm) antigens was significantly elevated in all infected groups but did not allow differentiation between cured and infected animals. Treatment with dexamethasone delayed worm elimination and temporarily reduced cellular response and parasite-specific IgG production but did not alter IgM reactivity. IgG2a anti-L3 and anti-Sv reactivity showed a progressive reduction, returning to baseline levels in ivermectin-treated rats. IgA anti-ES/L3 (excretory and secretory larval antigens) reactivity significantly decreased in intestinal wash after parasitological cure. These data would help the development of more efficient immunodiagnostic alternatives for human strongyloidiasis based on antibody isotype reactivity. Full article

Monoclonal antibodies (mAbs) are widely used as therapeutic molecules for the treatment of serious diseases, primarily cancer. The market for mAbs is one of the fastest-growing segments of the biopharmaceuticals industry. Purification is a crucial stage in the production of mAbs. While staphylococcal protein A (SpA) affinity chromatography remains the gold standard in industrial mAb purification, its limitations—low alkaline stability and insufficient binding capacity of SpA, as well as the need for harsh acidic elution conditions—have driven extensive efforts for novel progressive affinity ligands. This review focuses on the development and performance of bacterial protein-based affinity resins for the purification of class G immunoglobulins (IgGs), including conventional proteins A and G, the promising protein L, and the more recently discovered protein M (from M. genitalium), each offering unique specificities for different antibody fragments and species. Hybrid ligands combining domains from multiple bacterial proteins are also discussed, along with next-generation synthetic alternatives such as affibodies, affimers, nanobodies, etc., as well as peptide-based or mixed-mode ligands. The key finding is that the reliable and time-tested resins like those based on protein A continue to dominate the market, although future trends also point toward smaller, more stable, and cost-effective synthetic ligands for specific applications. Full article