Quantitative analysis of pertussis, tetanus, and diphtheria antibodies in sera and breast milk from Tdap vaccinated women using a qualified multiplex assay

Pertussis (whooping cough) is a reemergent, highly contagious respiratory infection of public health concern. Infants prior to initiation of their primary vaccination series are the most vulnerable to severe infection, and even death. Vaccination during pregnancy is an efficacious means of reducing infection in infants. This approach relies on boosting maternal immunity and passive transfer of antibodies to the infant via placenta and breast milk. Similarly, maternal vaccination post-partum can enhance maternal-infant immunity. To support the analysis of pertussis immunity in the context of maternal-infant immunization, we developed a high throughput multiplex assay for simultaneous quantification of serum IgG antibodies against pertussis vaccine antigens: pertussis toxin (PT), filamentous hemagglutinin (FHA), pertactin (PRN), and fimbriae (FIM2/3), and against tetanus (TT) and diphtheria toxoids (DT), using the Meso Scale Discovery (MSD) platform. The assay was qualified, and specificity, sensitivity, accuracy, precision, linearity, and robustness were demonstrated. The assay was subsequently adapted for quantification of IgG and IgA in breast milk. Applied to a serological survey of pregnant women living in the United States and sub-Saharan Africa, this method revealed differences in magnitude and breadth of antibody profile, consistent with history of vaccination. A longitudinal analysis of Tdap responses in women vaccinated post-partum demonstrated a rapid increase in serum IgG that remained elevated for up to 24 months. Likewise, high levels of vaccine-specific IgA and IgG antibodies were present in breast milk, although they exhibited faster decay. This multiplex MSD assay is a reliable and practical tool for quantification of pertussis, tetanus, and diphtheria antibodies in serum and breast milk in serosurveys or vaccine studies.

IMPORTANCE

Pertussis (whooping cough) has reemerged in recent years. Vaccination during pregnancy is an effective approach to prevent illness during the first months of life. We developed a multiplex assay for quantification of pertussis, tetanus, and diphtheria serum antibodies using the Meso Scale Discovery (MSD) platform; the method was qualified, and specificity, precision, accuracy, linearity, and limits of quantification were defined. It was also adapted for quantification of antibodies in breast milk. We successfully determined serostatus in women from different regions and with different vaccination histories, as well as responses to Tdap in blood and breast milk post-partum. This is the first description of a multiplex assay for the quantification of pertussis, tetanus, and diphtheria antibodies in breast milk.

Metabolomic Signatures Differentiate Immune Responses in Avian Influenza Vaccine Recipients

BACKGROUND

Avian influenza viruses pose significant risk to human health. Vaccines targeting the hemagglutinin of these viruses are poorly immunogenic without the use of adjuvants.

METHODS

Twenty healthy men and women (18-49 years of age) were randomized to receive two doses of inactivated influenza A/H5N1 vaccine alone (IIV) or with AS03 adjuvant (IIV-AS03) one month apart. Urine and serum samples were collected on day 0 and on days 1, 3, and 7 following first vaccination and subjected to metabolomics analyses to identify metabolites, metabolic pathways, and metabolite clusters associated with immunization.

RESULTS

Seventy-three differentially abundant (DA) serum and 88 urine metabolites were identified for any post-vaccination day comparison. Pathway analysis revealed enrichment of tryptophan, tyrosine and nicotinate metabolism in urine and serum among IIV-AS03 recipients. Increased urine abundance of 4-vinylphenol sulfate on Day 1 was associated with serologic response based on hemagglutination inhibition responses. In addition, 9 DA urine metabolites were identified in participants with malaise compared to those without.

CONCLUSIONS

Our findings suggest that tryptophan, tyrosine, and nicotinate metabolism are upregulated among IIV-AS03 recipients compared with IIV alone. Metabolites within these pathways may serve as measures of immunogenicity and may provide mechanistic insights for adjuvanted vaccines.

Safety and immunogenicity of live, attenuated intranasal Bordetella pertussis vaccine (BPZE1) in healthy adults

BACKGROUND

BPZE1 is a live, attenuated pertussis vaccine derived from B. pertussis strain Tohama I modified by genetic removal or inactivation of 3 B. pertussis toxins: pertussis toxin, dermonecrotic toxin, and tracheal cytotoxin. This Phase 2a study evaluated the safety and immunogenicity of liquid or lyophilized BPZE1 vaccine administered intranasally by needleless tuberculin syringe or mucosal atomization device (VaxINator^TM) at two dose levels.

METHODS

Fifty healthy male and non-pregnant female participants 18-49 years of age were enrolled. Participants were randomized 3:3:3:1 to a single lyophilized dose of 10⁷ colony forming units (CFU) BPZE1, 10⁹ CFU BPZE1, placebo via VaxINator device, or a single liquid dose of 10⁹ CFU BPZE1 via tuberculin syringe. Reactogenicity was assessed for 14 days. Blood was obtained pre-vaccination; on Day 8 (safety); and on Days 15, 29, and 181 (immunogenicity). Nasal wick and swab samples were obtained at baseline and on Days 29 and 181 for assessment of mucosal antibody responses and clearance of BPZE1.

RESULTS

Across all groups, 35/50 (70 %) experienced at least one local adverse event (AE) and 31/50 (62 %) experienced at least one systemic AE, with similar AE frequencies observed between the highest 10⁹ CFU BPZE1 and placebo groups. There were no severe or serious AEs during the study. At Day 29, seroconversion (≥2-fold rise from baseline in serum IgG or IgA) to at least 2 pertussis antigens was observed in 73 % in the 10⁹ CFU BPZE1 VaxINator group, 60 % in the 10⁹ CFU BPZE1 group delivered via tuberculin syringe, 27 % of participants in the 10⁷ CFU BPZE1 VaxINator group, and 20 % in the placebo VaxINator group. No participants were colonized with BPZE1 at Day 29 post vaccination.

DISCUSSION

Lyophilized BPZE1 vaccine was well tolerated and immunogenic at the highest dose (10⁹ CFU) delivered intranasally by VaxINator device and was not associated with any SAEs or prolonged shedding of BPZE1. Further evaluation of BPZE1 is warranted.

Humoral and cellular immune responses to the SARS-CoV-2 BNT162b2 vaccine among a cohort of solid organ transplant recipients and healthy controls

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with increased morbidity and mortality in solid organ transplant (SOT) recipients. Despite exclusion from SARS-CoV-2 vaccine clinical trials, these individuals were identified as high-risk and prioritized for vaccination in public health guidelines.

METHODS

We prospectively evaluated humoral and cellular immune responses to two doses of the SARS-CoV-2 mRNA vaccine, BNT162b2, in 56 SOT recipients and 26 healthy controls (HCs). Blood specimens collected from participants prior to each dose and following the second dose were tested for SARS-CoV-2-specific antibodies, as well as CD4+ and CD8+ T-cell responses.

RESULTS

SOT recipients demonstrated lower mean anti-SARS-CoV-2 antibody levels compared to HCs after each dose, and only 21.6% achieved an antibody response after the second dose within the range of HC responses. Similarly, the percentage of responsive CD4+ and CD8+ T cells in SOT recipients was lower than in HCs. While most HCs showed notable humoral and cellular responses, responses were less concordant in SOT recipients, with some showing evidence of either humoral or cellular response, but not both.

CONCLUSION

Humoral and cellular immune responses to the BNT162b2 vaccine are markedly reduced in SOT recipients as compared to HCs, suggesting that SOT recipients may benefit from more tailored regimens such as higher dose and/or additional vaccinations.

Standardized two-step testing of antibody activity in COVID-19 convalescent plasma

The COVID-19 pandemic revealed an urgent need for rapid profiling of neutralizing antibody responses and development of antibody therapeutics. The current Food and Drug Administration-approved serological tests do not measure antibody-mediated viral neutralization, and there is a need for standardized quantitative neutralization assays. We report a high-throughput two-step profiling approach for identifying neutralizing convalescent plasma. Screening and downselection for serum antibody binding to the receptor-binding domain are followed by quantitative neutralization testing using a chimeric vesicular stomatitis virus expressing spike protein of SARS-CoV-2 in a real-time cell analysis assay. This approach enables a predictive screening process for identifying plasma units that neutralize SARS-CoV-2. To calibrate antibody neutralizing activity in serum from convalescent plasma donors, we introduce a neutralizing antibody standard reagent composed of two human antibodies that neutralize SARS-CoV strains, including SARS-CoV-2 variants of concern. Our results provide a framework for establishing a standardized assessment of antibody-based interventions against COVID-19.

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A high-throughput approach enabling antibody activity testing in COVID-19 plasma

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SARS-CoV-2 IgG binding screen coupled with quantitative neutralization testing

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Neutralization testing is necessary for profiling COVID-19 convalescent plasma

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Two broad monoclonal antibodies identified as a neutralization testing standard

Cellular and humoral immune responses in adults receiving an inactivated mammalian cell-based influenza vaccine

Current evaluation of influenza vaccines focuses mainly on humoral response to surface hemagglutinin (HA), although both CD4 and CD8 T cell responses have been reported, to both HA and other viral proteins. We conducted a comprehensive functional analysis on the pre-existing and vaccine-induced immune responses to Flucelvax, a tetravalent mammalian cell-based influenza vaccine which in addition to HA contains additional viral proteins (NA, M1, M2, NP, NEP, NS1, PA, PB1, and PB2). Longitudinal samples of peripheral blood mononuclear cells from a cohort of 10 participants, were stimulated by pools of peptides overlapping individual influenza viral protein components. We examined both humoral and cellular responses, intra-vaccine interference, type-specific immunodominance patterns of responses and cytokine polarization. In addition to serological responses, our results demonstrated vaccine-induced CD4 and CD8 responses that were still present after 90 days post vaccination, a balanced immunogenicity across all 4 included viral strains, as well as unchanged type-specific immunodominance patterns and cytokine polarization post-vaccination. Our results demonstrated distinct CD4 reactivities mostly directed to HA/NA (neuraminidase) proteins in Influenza B strains, but similar CD8 responses to both influenza A and B viruses preferentially targeting the more conserved core viral proteins. The present study suggests that Flucelvax induces, both humoral, CD4 and CD8 cellular immunity, balanced across four different influenza strains and targeting HA and multiple additional viral antigens.

A high-throughput liquid bead array assay confirms strong correlation between SARS-CoV-2 antibody level and COVID-19 severity

A detailed understanding of the adaptive host response to SARS-CoV-2 infection in humans is urgently needed. We developed a sensitive, high-throughput, and efficient assay using liquid bead array technology. We observed advantages over traditional ELISA for the detection and quantification of binding IgG against the receptor binding domain (RBD) of SARS-CoV-2. To determine whether COVID-19 symptom severity correlates with SARS-CoV-2 IgG, we measured anti-RBD IgG levels from 67 subjects recovered from PCR-confirmed COVID-19. We found that COVID-19 symptom severity strongly correlated with RBD IgG level (p < 0.001). These findings have substantial implications for public policy surrounding assessments of antibody responses and possible immunity, as not all cases of COVID-19 can be assumed to generate a protective antibody response, and mild disease in particular is capable of generating very low-level anti-RBD IgG levels. These findings also have important implications for the selection of donors for convalescent plasma to be used therapeutically.

Reactogenicity and immunogenicity of tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis vaccine (Tdap) in pregnant and nonpregnant women

OBJECTIVE

Tetanus toxoid, reduced diphtheria toxoid, and acellular pertusiss (Tdap) vaccine is recommended during each pregnancy, regardless of prior receipt. Data on reactogenicity and immunogenicity, particularly after repeated Tdap, are limited. We compared local injection-site and systemic reactions and serologic response following Tdap in (1) pregnant and nonpregnant women and (2) pregnant women by self-reported prior Tdap receipt.

STUDY DESIGN

Pregnant women (gestational age 20-34 weeks) and nonpregnant women receiving Tdap were enrolled in this observational study. Injection-site and systemic reactions were assessed for one week post-vaccination. Pertussis toxin, filamentous hemagglutinin, pertactin, fimbriae, tetanus and diphtheria specific IgG antibody titers were determined by standardized enzyme-linked immunosorbent assay at baseline and 28 days post-vaccination. Reactogenicity and serologic responses were compared by pregnancy status, and within pregnant women by self-reported prior Tdap receipt.

RESULTS

374 pregnant and 225 nonpregnant women were vaccinated. Severe local or systemic reactions or "any" fever were uncommon (≤3% for both groups). Moderate/severe injection-site pain was significantly higher in pregnant (17.9%) versus nonpregnant (11.1%) women, but did not prompt a healthcare visit. Proportions of other moderate/severe or any severe reactions were not significantly higher in pregnant compared to nonpregnant women. Moderate/severe (including pain) and severe reactions were not significantly higher in pregnant women receiving repeat versus first-time Tdap. Antibody titers increased from baseline to post-vaccination for all vaccine antigens in pregnant and nonpregnant women; post-vaccination titers against pertussis toxin and filamentous hemagglutinin were significantly higher in nonpregnant versus pregnant women (p < 0.01).

CONCLUSION

Tdap was well-tolerated in pregnant and nonpregnant women. Pregnant women were more likely to report moderate/severe pain at the Tdap injection-site compared with nonpregnant women, but did not necessitate medical visits. Prior Tdap receipt did not increase occurrence of moderate/severe local or systemic reactions in pregnant women. Serologic responses to all vaccine antigens were robust. Clinical Trial Registration@ClinicalTrials.gov. NCT02209623. https://clinicaltrials.gov/ct2/show/NCT02209623.

The relationship of TP53 R72P polymorphism to disease outcome and TP53 mutation in myelodysplastic syndromes

Nonsynonymous TP53 exon 4 single-nucleotide polymorphism (SNP), R72P, is linked to cancer and mutagen susceptibility. R72P associations with specific cancer risk, particularly hematological malignancies, have been conflicting. Myelodysplastic syndrome (MDS) with chromosome 5q deletion is characterized by erythroid hypoplasia arising from lineage-specific p53 accumulation resulting from ribosomal insufficiency. We hypothesized that apoptotically diminished R72P C-allele may influence predisposition to del(5q) MDS. Bone marrow and blood DNA was sequenced from 705 MDS cases (333 del(5q), 372 non-del(5q)) and 157 controls. Genotype distribution did not significantly differ between del(5q) cases (12.6% CC, 38.1% CG, 49.2% GG), non-del(5q) cases (9.7% CC, 44.6% CG, 45.7% GG) and controls (7.6% CC, 37.6% CG, 54.8% GG) (P=0.13). Allele frequency did not differ between non-del(5q) and del(5q) cases (P=0.91) but trended towards increased C-allele frequency comparing non-del(5q) (P=0.08) and del(5q) (P=0.10) cases with controls. Median lenalidomide response duration increased proportionate to C-allele dosage in del(5q) patients (2.2 (CC), 1.3 (CG) and 0.89 years (GG)). Furthermore, C-allele homozygosity in del(5q) was associated with prolonged overall and progression-free survival and non-terminal interstitial deletions that excluded 5q34, whereas G-allele homozygozity was associated with inferior outcome and terminal deletions involving 5q34 (P=0.05). These findings comprise the largest MDS R72P SNP analysis.

Cellular immunity in adolescents and adults following acellular pertussis vaccine administration

Cell-mediated immune (CMI) responses to an acellular pertussis vaccine administered to 49 subjects, a subset of participants in the National Institutes of Health-funded adult acellular pertussis vaccine efficacy trial, were evaluated and compared with antibody responses to vaccine antigens. Levels of proliferation of and cytokine secretion from lymphocytes cultured in the presence of pertussis toxin, filamentous hemagglutinin, or pertactin were measured before vaccination and 1 month and 1 year after vaccination. Statistically significant increases in lymphocyte stimulation indices and cytokine secretion were noted at both 1 month and 1 year after vaccination. Brisk pertussis antigen-specific immunoglobulin G responses were also noted at 1 month after vaccination, but these responses had declined by nearly 50% at 1 year after vaccination. These studies clearly demonstrate that both cellular and humoral immune responses occur after the administration of acellular pertussis vaccines to adolescents and adults but that the CMI responses are of greater magnitude and longer duration. CMI responses may be a better correlate of long-term protection.

Expression of Streptococcus mutans wall-associated protein A gene in Chinese hamster ovary cells: prospect for a dental caries DNA vaccine

The Streptococcus mutans strain GS-5 wall-associated protein A (Wap-A) is a precursor to the extracellular antigen A (AgA), a recognized candidate dental caries vaccine. The full-length wapA gene (wapA-E) and a C-terminal truncated version (wapA-G) encoding the AgA were cloned into the mammalian expression vector pcDNA 3.1/V5/His-TOPO. The resulting constructs were propagated in the Escherichia coli Top10. To investigate the expression of the S. mutans genes in mammalian cells, the above constructs were used to transfect Chinese hamster ovary (CHO) cells in the presence of the cationic lipid pfx-8. Transient expression of the wapA-E and wapA-G genes was observed at 24 h post-transfection, as shown by Western immunoblot analysis using a rabbit antiserum to S. mutans cell wall. Immunochemical staining of the transfected CHO cells showed expression of WapA mainly in the cells and budding vesicles, whereas AgA was found mainly in the transfected cells and extracellular medium. The expression of S. mutans proteins in CHO cells, in either vesicles or soluble form, suggested an antibody response to the above DNA constructs. Work is under way to test the efficacy of these as DNA vaccines against S. mutans.

Factors predicting return to work following mild traumatic brain injury: a discriminant analysis

Studies of mild traumatic brain injury (MTBI) suggest that most individuals recover rapidly and return to their everyday activities. However, a percentage of MTBI patients report persistent problems with cognitive, physical, and emotional symptoms. There is also evidence that some experience changes in occupational functioning following MTBI. The current study used a stepwise discriminant function analysis (DFA) to examine the role of injury severity variables, cognitive performance, and ratings of symptoms of TBI in predicting work status following MTBI. Subjects included 121 MTBI patients who were all active-duty military personnel. The stepwise DFA revealed that age and three cognitive variables (verbal memory, verbal fluency, and a speed test of planning and strategy) were predictive of work status 3-15 months following a documented MTBI, correctly classifying work status 68.8% of the time. A cross-validation DFA was conducted, with a 66.1% correct classification rate. These findings highlight the importance of cognitive impairments in identifying those at risk for occupational impairment following MTBI.

High-level expression of a truncated wall-associated protein A from the dental cariogenic Streptococcus mutans

Streptococcus mutans plays a primary role in the formation of dental caries. Previously, in our laboratory, an S. mutans genomic library was prepared, and the wapA gene was cloned into the shuttle vector, pSA4/4B2. To generate overexpression of wapA and to facilitate efficient purification of the WapA protein for use as an immunogen, an expression vector with the strong tac promoter was used. In order to answer questions regarding the optimization of solubility and expression based on gene size or the hydrophobicity of the protein product, 12 truncated constructs of the wapA gene were prepared using PCR. The truncated products were subcloned into the pGEX-6P-1 glutathione S-transferase (GST) fusion vector and expressed in E. coli BL21. The fusion proteins were analyzed by SDS-PAGE and confirmed by analysis with anti-GST and anti-WapA antibodies. Our study suggests that abrogation of the wapA promoter is necessary for expression of this gene in this expression system. Deletion of the signal peptide and the hydrophobic C terminus of WapA increased expression compared with the full-length construct, and truncation at the protease cleavage site of the C-terminal region greatly increased the stability of the protein without a loss in reactivity with the anti-WapA antibody. Western immunoblot analysis with anti-WapA antiserum clearly showed that the majority of the epitopes of the GST-WapA fusions are located in the N-terminal region of WapA. The immunogenicity of the various WapA fusion products is being examined in mice and rats to further map the immunologically dominant regions of the protein. This method effectively increased the expression of WapA and should contribute to the further understanding of gene expression of E. coli, as well as aid in the characterization of this protein for future immunologic evaluation.

Isolation and identification of nontuberculous mycobacteria from foods as possible exposure sources

A variety of foods collected from local supermarkets and produce stands were examined as possible sources of nontuberculous mycobacterial exposure. Food samples were combined with sterile ultrapure water and manually shaken. To remove large particles, the suspensions were filtered through a sterile strainer, centrifuged, and the supernatants were discarded. The food pellets were stored at -75 degrees C. The pellets were treated with either oxalic acid or sodium hydroxide-sodium citrate solutions to reduce contamination by nonmycobacterial organisms. Decontaminated pellets were cultured on both Middlebrook 7H10C agar and Middlebrook 7H10C agar with supplemental malachite green. Plates were observed for growth at 2 and 8 weeks. Isolates demonstrating acid-fastness were identified to species using polymerase chain reaction and restriction enzyme analysis. Nontuberculous mycobacteria (NTM) were recovered from 25 of 121 foods. Six different species of NTM were isolated, the most predominant being Mycobacterium avium.

PCR comparison of Mycobacterium avium isolates obtained from patients and foods

Mycobacterium avium is a cause of disseminated disease in AIDS patients. A need for a better understanding of possible sources and routes of transmission of this organism has arisen. This study utilized a PCR typing method designed to amplify DNA segments located between the insertion sequences IS1245 and IS1311 to compare levels of relatedness of M. avium isolates found in patients and foods. Twenty-five of 121 food samples yielded 29 mycobacterial isolates, of which 12 were M. avium. Twelve food and 103 clinical M. avium isolates were tested. A clinical isolate was found to be identical to a food isolate, and close relationships were found between two patient isolates and two food isolates. Relatedness between food isolates and patient isolates suggests the possibility that food is a potential source of M. avium infection. This study demonstrates a rapid, inexpensive method for typing M. avium, possibly replacing pulsed-field gel electrophoresis.