Carbohydrate antigens Lewis a and Lewis b act as tumor markers cooperating with CA19.9 in the management of PDAC patients.

BACKGROUND: CA19.9 is the unique marker recommended for the preoperative staging and the follow-up of patients suffering from pancreatic ductal adenocarcinoma (PDAC) but up to 30% of PDAC patients maintain normal CA19.9 values and cannot be monitored in this way. Lewis a (Lea Galß1,3[Fucα1,4]GlcNAc) and b (Leb, Fucα1,2Galß1,3[Fucα1,4]GlcNAc) are antigens which are structurally similar to sialyl-Lewis a (Siaα2,3Galß1,3[Fucα1,4]GlcNAc), the epitope of CA19.9. METHODS: We set an ELISA procedure determining the levels of Lea, Leb, and CA19.9 in the blood of healthy individuals or PDAC patients. Moreover, such antigens were also detected in cancer resections by immunofluorescence microscopy, and the levels of glycosyltransferase transcripts involved in Lewis antigen biosynthesis were determined by RT-qPCR. RESULTS: In our cohort of 116 healthy individuals, the distribution of circulating Lea and Leb was similar to that of CA19.9, allowing us to set putative cutoff values for both antigens. In a cohort of 115 PDAC patients, the differential distribution with respect to the controls was statistically significant for both antigens (p < 0.001). Out of 37 patients presenting normal CA19.9 values, 15 patients presented Lea or Leb above the cutoffs. By immunofluorescence, Lea, Leb and CA19.9 were all detected in cancer resections and expression levels were heterogeneous among patients in terms of intensity, localization and diffusion. The levels of relevant glycosyltransferase transcripts were found to be heterogeneous between cancers of different patients and no association was detectable with the levels of any circulating antigen. CONCLUSIONS: The concurrent quantification of Lea and Leb together with CA19.9 improves the management of PDAC patients.

Genomic comparison between Mycobacterium bovis and Mycobacterium microti and in silico analysis of peptide-based biomarkers for serodiagnosis.

In recent years, there has been an increase in the number of reported cases of Mycobacterium microti infection in various animals, which can interfere with the ante-mortem diagnosis of animal tuberculosis caused by Mycobacterium bovis. In this study, whole genome sequencing (WGS) was used to search for protein-coding genes to distinguish M. microti from M. bovis. In addition, the population structure of the available M. microti genomic WGS datasets is described, including three novel Belgian isolates from infections in alpacas. Candidate genes were identified by examining the presence of the regions of difference and by a pan-genome analysis of the available WGS data. A total of 80 genes showed presence-absence variation between the two species, including genes encoding Proline-Glutamate (PE), Proline-Proline-Glutamate (PPE), and Polymorphic GC-Rich Sequence (PE-PGRS) proteins involved in virulence and host interaction. Filtering based on predicted subcellular localization, sequence homology and predicted antigenicity resulted in 28 proteins out of 80 that were predicted to be potential antigens. As synthetic peptides are less costly and variable than recombinant proteins, an in silico approach was performed to identify linear and discontinuous B-cell epitopes in the selected proteins. From the 28 proteins, 157 B-cell epitope-based peptides were identified that discriminated between M. bovis and M. microti species. Although confirmation by in vitro testing is still required, these candidate synthetic peptides containing B-cell epitopes could potentially be used in serological tests to differentiate cases of M. bovis from M. microti infection, thus reducing misdiagnosis in animal tuberculosis surveillance.

No association between migraine and HLA alleles in a cohort of 13,210 individuals with migraine from the Danish Blood Donor Study.

OBJECTIVE: To determine the association between human leukocyte antigen (HLA) alleles and migraine, migraine subtypes, and sex-specific factors. BACKGROUND: It has long been hypothesized that inflammation contributes to migraine pathophysiology. This study examined the association between migraine and alleles in the HLA system, a key player in immune response and genetic diversity. METHODS: We performed a case-control study and included 13,210 individuals with migraine and 86,738 controls. All participants were part of the Danish Blood Donor Study Genomic Cohort. Participants were genotyped and 111 HLA alleles on 15 HLA genes were imputed. We examined the association between HLA alleles and migraine subtypes, considering sex-specific differences. RESULTS: We found no association between HLA alleles and migraine, neither overall, nor in the sex-specific analysis. In the migraine subtype analysis, three HLA alleles were associated with migraine without aura; however, these associations could not be replicated in an independent Icelandic cohort (2191 individuals with migraine without aura and 278,858 controls). Furthermore, we found no association between HLA alleles and migraine with aura or chronic migraine. CONCLUSION: We found no evidence of an association between the HLA system and migraine, suggesting that genetic factors related to the HLA system do not play a significant role in migraine susceptibility.

Food antigens suppress small intestinal tumorigenesis.

Food components suppressing small intestinal tumorigenesis are not well-defined partly because of the rarity of this tumor type compared to colorectal tumors. Using Apcmin/+ mice, a mouse model for intestinal tumorigenesis, and antigen-free diet, we report here that food antigens serve this function in the small intestine. By depleting Peyer's patches (PPs), immune inductive sites in the small intestine, we found that PPs have a role in the suppression of small intestinal tumors and are important for the induction of small intestinal T cells by food antigens. On the follicle-associated epithelium (FAE) of PPs, microfold (M) cells pass food antigens from lumen to the dendritic cells to induce T cells. Single-cell RNA-seq (scRNA-seq) analysis of immune cells in PPs revealed a significant impact of food antigens on the induction of the PP T cells and the antigen presentation capacity of dendritic cells. These data demonstrate the role of food antigens in the suppression of small intestinal tumorigenesis by PP-mediated immune cell induction.

Associations between Histo-Blood Group Antigen Status in Mother-Infant Dyads and Infant Oral Rotavirus Vaccine Immunogenicity in rural Zimbabwe.

INTRODUCTION: Histo-blood group antigen (HBGA) phenotypes may contribute to poor oral rotavirus vaccine (RVV) immunogenicity, since rotavirus binds intestinal epithelial HBGA glycans, while maternal HBGA status shapes breastmilk composition, which influences the composition of the infant microbiome. We investigated associations between maternal/infant HBGA phenotypes and RVV immunogenicity in rural Zimbabwe. METHODS: We undertook salivary FUT2/FUT3 phenotyping in mother-infant pairs. Serum anti-rotavirus IgA was measured by ELISA. We explored adjusted associations between FUT2/FUT3 status and RVV seroconversion (primary outcome, N=322), and seropositivity and geometric mean titre (secondary outcomes, N=776). RESULTS: Infants of FUT2-positive or FUT3-positive women were less likely to seroconvert post-RVV than infants of FUT2-negative or FUT3-negative women (FUT2-positive 20.1% versus FUT2-negative 27.5%, adjusted relative risk (aRR) 0.47, 95%CI 0.26, 0.82; P=0.008; FUT3-positive 18.1% versus FUT3-negative 30.0%, aRR 0.45, 95%CI 0.25, 0.78; P=0.005). Compared to FUT2-positive infants with FUT2-positive mothers, FUT2-positive infants with FUT2-negative mothers were twice as likely to seroconvert (36.8% versus 21.9%, aRR 2.12, 95%CI 1.23, 3.63; P=0.006). Compared to FUT3-positive infants with FUT3-positive mothers, FUT3-positive infants with FUT3-negative mothers were three times as likely to seroconvert (48.3% versus 18.2%, aRR 2.99, 95%CI 1.82, 4.90; P<0.001). CONCLUSIONS: Maternal and infant FUT2 and FUT3 status influences infant RVV immunogenicity.

HPV16 mutant E6/E7 construct is protective in mouse model.

BACKGROUND: Human papillomavirus type 16 (HPV-16) infection is strongly associated with considerable parts of cervical, neck, and head cancers. Performed investigations have had moderate clinical success, so research to reach an efficient vaccine has been of great interest. In the present study, the immunization potential of a newly designed HPV-16 construct was evaluated in a mouse model. RESULTS: Initially, a construct containing HPV-16 mutant (m) E6/E7 fusion gene was designed and antigen produced in two platforms (i.e., DNA vaccine and recombinant protein). Subsequently, the immunogenicity of these platforms was investigated in five mice) C57BL/6 (groups based on several administration strategies. Three mice groups were immunized recombinant protein, DNA vaccine, and a combination of them, and two other groups were negative controls. The peripheral blood mononuclear cells (PBMCs) proliferation, Interleukin-5 (IL-5) and interferon-γ (IFN-γ) cytokines, IgG1 and IgG2a antibody levels were measured. After two weeks, TC-1 tumor cells were injected into all mice groups, and subsequently further analysis of tumor growth and metastasis and mice survival were performed according to the schedule. Overall, the results obtained from in vitro immunology and tumor cells challenging assays indicated the potential of the mE6/E7 construct as an HPV16 therapeutic vaccine candidate. The results demonstrated a significant increase in IFN-γ cytokine (P value < 0.05) in the Protein/Protein (D) and DNA/Protein (E) groups. This finding was in agreement with in vivo assays. Control groups show a 10.5-fold increase (P value < 0.001) and (C) DNA/DNA group shows a 2.5-fold increase (P value < 0.01) in tumor growth compared to D and E groups. Also, a significant increase in survival of D and E (P value < 0.001) and C (P value < 0.01) groups were observed. CONCLUSIONS: So, according to the findings, the recombinant protein could induce stronger protection compared to the DNA vaccine form. Protein/Protein and DNA/Protein are promising administration strategies for presenting this construct to develop an HPV-16 therapeutic vaccine candidate.

Human leukocyte antigen compatibility and incidence of donor-specific antibodies in pediatric liver transplant recipients.

BACKGROUND: Antibody-mediated rejection following liver transplantation (LT) has been increasingly recognized, particularly with respect to the emergence of de novo donor-specific antibodies (DSAs) and their impact on graft longevity. While substantial evidence for adult populations exists, research focusing on pediatric LT outcomes remains limited. AIM: To investigate the prevalence of human leukocyte antigen (HLA) mismatches and DSA and evaluate their association with rejection episodes after pediatric LT. METHODS: A cohort of pediatric LT recipients underwent HLA testing at Santa Casa de Porto Alegre, Brazil, between December 2013 and December 2023. Only patients who survived for > 30 days after LT with at least one DSA analysis were included. DSA classes I and II and cross-matches were analyzed. The presence of de novo DSA (dnDSA) was evaluated at least 3 months after LT using the Luminex® single antigen bead method, with a positive reaction threshold set at 1000 MFI. Rejection episodes were confirmed by liver biopsy. RESULTS: Overall, 67 transplanted children were analyzed; 61 received grafts from living donors, 85% of whom were related to recipients. Pre-transplant DSA (class I or II) was detected in 28.3% of patients, and dnDSA was detected in 48.4%. The median time to DSA detection after LT was 19.7 [interquartile range (IQR): 4.3-35.6] months. Biopsy-proven rejection occurred in 13 patients at follow-up, with C4d positivity observed in 5/13 Liver biopsies. The median time to rejection was 7.8 (IQR: 5.7-12.8) months. The presence of dnDSA was significantly associated with rejection (36% vs 3%, P < 0.001). The rejection-free survival rates at 12 and 24 months were 76% vs 100% and 58% vs 95% for patients with dnDSA anti-DQ vs those without, respectively. CONCLUSION: Our findings highlight the importance of incorporating DSA assessment into pre- and post-transplantation protocols for pediatric LT recipients. Future implications may include immunosuppression minimization strategies based on this analysis in pediatric LT recipients.

The American Rare Donor Program: 25 years supporting rare blood needs.

Rare donor programs are critically important for those patients with rare phenotypes who have produced the associated alloantibodies that necessitate the provision of rare blood components. We describe the American Rare Donor Program (ARDP) and its establishment, members, and policies. The specific phenotypes meeting the ARDP criteria for inclusion are described. Data on the number of rare donors registered by year, and the number of requests for rare blood components received and fulfilled over the 25 years of the program (1998-2023) are provided, along with a description of some notable cases and discussion of how the program supports patients with sickle cell disease.

Insights into the CD1 lipidome.

CD1 isoforms are MHC class I-like molecules that present lipid-antigens to T cells and have been associated with a variety of immune responses. The lipid repertoire bound and presented by the four CD1 isoforms may be influenced by factors such as the cellular lipidome, subcellular microenvironment, and the properties of the binding pocket. In this study, by shotgun mass spectrometry, we performed a comprehensive lipidomic analysis of soluble CD1 molecules. We identified 1040 lipids, of which 293 were present in all isoforms. Comparative analysis revealed that the isoforms bind almost any cellular lipid.CD1a and CD1c closely mirrored the cellular lipidome, while CD1b and CD1d showed a preference for sphingolipids. Each CD1 isoform was found to have unique lipid species, suggesting some distinct roles in lipid presentation and immune responses. These findings contribute to our understanding of the role of CD1 system in immunity and could have implications for the development of lipid-based therapeutics.

The potential of human leukocyte antigen alleles to assist with multiple-contributor DNA mixtures: Proof of concept study.

One of the most challenging issues still present in forensic DNA analysis is identifying individuals in samples containing DNA from multiple contributors. The introduction of novel identification markers may be a useful tool in the deconvolution of such DNA mixtures. In this study, we investigated the potential of alleles from the human leukocyte antigen system (HLA) to aid in identifying individuals in complex, multiple-donor DNA samples. The most advantageous characteristic of the HLA complex is its polymorphism in the human genome. A 22-loci multiplex with HLA markers was designed and applied to two-, three-, and four-person DNA mixtures. The results of the conducted experiments demonstrated that the identification of individuals in multiple contributor samples with the help of HLA markers is possible; however, it is clear that the reliability of the method is heavily dependent on the number of unique alleles for each individual in the analysed mixture. In order to compare this novel approach against the already established process, the same group of reference and multiple-contributor samples was analysed with a commonly used set of STR markers. This proof-of-concept research shows the importance of examining alternative solutions to the current deconvolution challenge in forensic DNA profiling.

Ligand-induced segregation from large cell-surface phosphatases is a critical step in γδ TCR triggering.

Gamma/delta (γδ) T cells are unconventional lymphocytes that recognize diverse ligands via somatically recombined T cell antigen receptors (γδ TCRs). The molecular mechanism by which ligand recognition initiates γδ TCR signaling, a process known as TCR triggering, remains elusive. Unlike αß TCRs, γδ TCRs are not mechanosensitive and do not require co-receptors or typical binding-induced conformational changes for triggering. Here, we show that γδ TCR triggering by nonclassical MHC class Ib antigens, a major class of ligands recognized by γδ T cells, requires steric segregation of the large cell-surface phosphatases CD45 and CD148 from engaged TCRs at synaptic close-contact zones. Increasing access of these inhibitory phosphatases to sites of TCR engagement, by elongating MHC class Ib ligands or truncating CD45/148 ectodomains, abrogates TCR triggering and T cell activation. Our results identify a critical step in γδ TCR triggering and provide insight into the core triggering mechanism of endogenous and synthetic tyrosine-phosphorylated immunoreceptors.

Phosphorylation-dependent immunomodulatory properties of B.PAT polysaccharide isolated from Bifidobacterium animalis ssp. animalis CCDM 218.

A wide range of articles describe the role of different probiotics in the prevention or treatment of various diseases. However, currently, the focus is shifting from whole microorganisms to their easier-to-define components that can confer similar or stronger benefits on the host. Here, we aimed to describe polysaccharide B.PAT, which is a surface antigen isolated from Bifidobacterium animalis ssp. animalis CCDM 218 and to understand the relationship between its structure and function. For this reason, we determined its glycerol phosphate-substituted structure, which consists of glucose, galactose, and rhamnose residues creating the following repeating unit: To fully understand the role of glycerol phosphate substitution on the B.PAT function, we prepared the dephosphorylated counterpart (B.MAT) and tested their immunomodulatory properties. The results showed that the loss of glycerol phosphate increased the production of IL-6, IL-10, IL-12, and TNF-α in bone marrow dendritic cells alone and after treatment with Lacticaseibacillus rhamnosus GG. Further studies indicated that dephosphorylation can enhance B.PAT properties to suppress IL-1ß-induced inflammatory response in Caco-2 and HT-29 cells. Thus, we suggest that further investigation of B.PAT and B.MAT may reveal distinct functionalities that can be exploited in the treatment of various diseases and may constitute an alternative to probiotics.

Major reduction in occurrence of anti-c and anti-E in pregnancy after more than 10 years of preventive matched transfusion with most benefit for c-matching.

Extension with cE-matching of the transfusion policy for women under 45 years to prevent alloimmunization and hemolytic disease of the foetus and newborn (HDFN) was evaluated. After implementation of cEK-matching, anti-c occurrence decreased from 46.8 to 30.4 per 100 000 pregnancies (RR 0.65, 95% CI 0.54-0.79), while anti-E occurrence decreased from 122.1 to 89.9 per 100 000 pregnancies (RR 0.74, 95% CI 0.66-0.84). The c-negative women showed a higher anti-E occurrence before cEK-matching and a more pronounced decline with the new policy. This indicates that cEK-matched transfusion effectively reduces alloimmunization, and that a cK-matched approach could prevent most transfusion-related alloimmunization and HDFN.

Identification of ferroptosis-associated tumor antigens as the potential targets to prevent head and neck squamous cell carcinoma.

Head and neck squamous cell carcinoma (HNSC) represents nearly 90% of all head and neck tumors. The current treatment modality for HNSC patients primarily involves surgical intervention and radiotherapy, but its therapeutic efficacy remains limited. The mRNA vaccine based on tumor antigens seems promising for cancer treatment. Ferroptosis, a novel form of cell death, is linked to tumor progression and cancer immunotherapy. Nevertheless, the effectiveness of ferroptosis-associated tumor antigens in treating HNSC remains uncertain. In this study, we identified three ferroptosis-associated tumor antigens, namely caveolin1 (CAV1), ferritin heavy chain (FTH1), and solute carrier 3A2 (SLC3A2), as being overexpressed and mutated based on data obtained from The Cancer Genome Atlas and Gene Expression Omnibus databases. These antigens were strongly associated with poor prognosis and infiltration of antigen-presenting cells in HNSC. We further identified two ferroptosis subtypes (FS1 and FS2) with distinct molecular, cellular, and clinical properties to identify antigen-sensitive individuals. Our findings indicate that FS1 exhibits an immune "hot" phenotype, whereas FS2 displays an immune "cold" phenotype. Additionally, differential expression of immunogenic cell death modulators and immune checkpoints was observed between these two immune subtypes. Further exploration of the HNSC's immune landscape revealed significant heterogeneity among individual patients. Our findings suggest that CAV1, FTH1, and SLC3A2 are potential targets to prevent HNSC in FS2 patients. Overall, our research reveals the potential of ferroptosis-associated mRNA vaccines for HNSC and identifies an effective patient population for vaccine treatment.

40 years of autoantibody research in paraneoplastic neurological syndromes.

Paraneoplastic neurologic syndromes (PNS) are a group of disorders that affect the central and the peripheral nervous system and frequently occur in patients with cancer which usually still is undiagnosed by the time the patient presents the first neurological manifestations. The discovery in the serum and cerebrospinal fluid of PNS patients of antibodies that target tumor antigens that also are normally expressed in the nervous system had a significant impact. First, the research on neuronal antibodies confirmed that most PNS are autoimmune disorders triggered by the underlying cancer supporting the use of immunotherapy to treat them; second, although the first antibodies described recognized intracellular neuronal antigens and therefore they were not pathogenic, these antibodies became robust biomarkers for the strict diagnosis of PNS; and third, the methodological approach used to characterize the first neuronal antibodies paved the way to the identification of antibodies against neuronal surface antigens that are pathogenic and responsible for some PNS and non-paraneoplastic encephalitis. Future studies should address several issues: (1) to improve the efficiency of commercial kits; (2) to provide strict criteria to select which neural antibodies should be used for the diagnosis of PNS; and (3) define in more detail the autoimmune mechanisms responsible for the brain injury in the PNS.

The GPI sidechain of Toxoplasma gondii inhibits parasite pathogenesis.

Glycosylphosphatidylinositols (GPIs) are highly conserved anchors for eukaryotic cell surface proteins. The apicomplexan parasite, Toxoplasma gondii, is a widespread intracellular parasite of warm-blooded animals whose plasma membrane is covered with GPI-anchored proteins, and free GPIs called GIPLs. While the glycan portion is conserved, species differ in sidechains added to the triple mannose core. The functional significance of the Glcα1,4GalNAcß1- sidechain reported in Toxoplasma gondii has remained largely unknown without understanding its biosynthesis. Here we identify and disrupt two glycosyltransferase genes and confirm their respective roles by serology and mass spectrometry. Parasites lacking the sidechain on account of deletion of the first glycosyltransferase, PIGJ, exhibit increased virulence during primary and secondary infections, suggesting it is an important pathogenesis factor. Cytokine responses, antibody recognition of GPI-anchored SAGs, and complement binding to PIGJ mutants are intact. By contrast, the scavenger receptor CD36 shows enhanced binding to PIGJ mutants, potentially explaining a subtle tropism for macrophages detected early in infection. Galectin-3, which binds GIPLs, exhibits an enhancement of binding to PIGJ mutants, and the protection of galectin-3 knockout mice from lethality suggests that Δpigj parasite virulence in this context is sidechain dependent. Parasite numbers are not affected by Δpigj early in the infection in wild-type mice, suggesting a breakdown of tolerance. However, increased tissue cysts in the brains of mice infected with Δpigj parasites indicate an advantage over wild-type strains. Thus, the GPI sidechain of T. gondii plays a crucial and diverse role in regulating disease outcomes in the infected host.IMPORTANCEThe functional significance of sidechain modifications to the glycosylphosphatidylinositol (GPI) anchor in parasites has yet to be determined because the glycosyltransferases responsible for these modifications have not been identified. Here we present identification and characterization of both Toxoplasmsa gondii GPI sidechain-modifying glycosyltransferases. Removal of the glycosyltransferase that adds the first GalNAc to the sidechain results in parasites without a sidechain on the GPI, and increased host susceptibility to infection. Loss of the second glycosyltransferase results in a sidechain with GalNAc alone, and no glucose added, and has negligible effect on disease outcomes. This indicates GPI sidechains are fundamental to host-parasite interactions.

COMPARING vaccine manufacturing technologies recombinant DNA vs in vitro transcribed (IVT) mRNA.

Vaccine manufacturing fosters the prevention, control, and eradication of infectious diseases. Recombinant DNA and in vitro (IVT) mRNA vaccine manufacturing technologies were enforced to combat the recent pandemic. Despite the impact of these technologies, there exists no scientific announcement that compares them. Digital Shadows are employed in this study to simulate each technology, investigating root cause deviations, technical merits, and liabilities, evaluating cost scenarios. Under this lens we provide an unbiased, advanced comparative technoeconomic study, one that determines which of these manufacturing platforms are suited for the two types of vaccines considered (monoclonal antibodies or antigens). We find recombinant DNA technology to exhibit higher Profitability Index due to lower capital and starting material requirements, pertaining to lower Minimum Selling Price per Dose values, delivering products of established quality. However, the potency of the mRNA, the streamlined and scalable synthetic processes involved and the raw material availability, facilitate faster market penetration and product flexibility, constituting these vaccines preferable whenever short product development cycles become a necessity.

Assessment of erythrocyte alloimmunization among patients treated at a Brazilian university hospital.

INTRODUCTION: Alloimmunization and transfusion reactions underscore the crucial role of precise immunohematological techniques to enhance safety in transfusion. This study aims to determine the frequency of alloimmunization in patients treated at a Brazilian university hospital, investigate demographic, clinical, and epidemiological characteristics of patients with positive irregular antibody screening, as well as to assess the frequency of erythrocyte antigens and anti-erythrocyte antibodies in the population. MATERIALS AND METHODS: This retrospective observational study included all irregular antibody-positive patients treated at the transfusion service of Hospital de Clínicas of the Federal University of Uberlandia between January 2019 and December 2020. RESULTS: Of the 201 irregular antibody-positive patients, alloimmunization was more common in women (64.2%) than in men (35.8%). Blood groups A (39.8%) and O (38.8%), and Rh positive samples (69.1%) predominated, and about half (48.2%) of the patients were transfused for preoperative procedures. The most frequently found clinically significant alloantibodies were anti-D (27.2%), anti-E (15.0%), and anti-Kell (11.5%). Of the patients, 30.6% had multiple antibody associations, with anti-D and anti-C being the most common combination. Erythrocyte immunophenotyping was performed for 76 patients with the most frequent antigens detected being e (100%), c (86.8%), and C (40.8%). Among the 14 pregnant women evaluated, most were multiparous, 85.7% had anti-D as the most prevalent antibody, and had the A-negative blood type (33.3%). CONCLUSION: Alloantibody screening and identification associated with erythrocyte immunophenotyping are necessary for a better understanding of the alloimmunized population, ensuring greater safety and efficacy of transfusion therapy in the hospital setting.

Development and validation of carbodiimide-activated ELISA plate for quantifying IgG levels against Streptococcus pneumoniae capsular polysaccharides.

Background: Conventional microtiter plates lack the surface strength needed for effective binding of pneumococcal polysaccharide antigens. This study tackles the limitation by altering the surface of polystyrene plates through carbodiimide activation under acidic pH conditions.Method: The microtiter plates were activated with carbodiimide coupling agents, N,N'-Dicyclohexylcarbodiimide (DCC) and N-Hydroxysuccinimide (NHS). They were subsequently coated with 13 pneumococcal antigens at a concentration of 5 µg/ml with a pH of 3.5. The IgG antibody titer was assessed utilizing the World Health Organization (WHO) ELISA protocol for 30 human serum samples. In addition, validation experiments were conducted to evaluate specificity and precision.Results: The modified plates exhibited two-times higher antibody titers compared to conventional plates across all 13 serotypes. Observations revealed elevated antibody levels, with geometric concentrations ranging between 0.96 µg/ml and 4.24 µg/ml.Conclusion: Carbodiimide activation and acidic pH modification of microtiter plates enhance sensitivity and specificity in detecting pneumococcal antibodies, critical for vaccination planning and immunity assessment.

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