Despite robust antibody responses, immunity induced by acellular pertussis vaccine (DTaP) wanes over time and risk of pertussis seems to be lower in children who receive whole-cell vaccine (DTP) as their first dose. To interrogate the early immunologic response to pertussis vaccine, we enrolled 56 healthy infants who received either DTP or DTaP at 2-, 4-, 6-, and 18-months of age. RNA-sequencing and ribosome profiling of PBMC were performed prior to vaccination (Day 1) and on either Day 2 or Day 8. Pathway enrichment analysis on Days 2 and 8 showed enrichment of TLR-signaling and FcϒR-mediated phagocytosis among DTP recipients. DTP also led to increases in IRAK-4 and IL-1ß. After booster vaccination, a higher frequency of PT-specific B-cells was observed in DTP- vs. DTaP recipients. These data provide insights into the early immunologic responses to pertussis vaccine and may guide next-generation pertussis vaccine development.

ABSTRACT Cellular and molecular characterization of immune responses elicited by influenza virus infection and seasonal vaccination have informed efforts to improve vaccine efficacy, breadth, and longevity. Here, we use negative stain electron microscopy polyclonal epitope mapping (nsEMPEM) to structurally characterize the humoral IgG antibody responses to hemagglutinin (HA) from human patients vaccinated with a seasonal quadrivalent flu vaccine or infected with influenza A viruses. Our data show that both vaccinated and infected patients had humoral IgGs targeting highly conserved regions on both H1 and H3 subtype HAs, including the stem and anchor, which are targets for universal influenza vaccine design. Responses against H1 predominantly targeted the central stem epitope in infected patients and vaccinated donors, whereas head epitopes were more prominently targeted on H3. Responses against H3 were less abundant, but a greater diversity of H3 epitopes were targeted relative to H1. While our analysis is limited by sample size, on average, vaccinated donors responded to a greater diversity of epitopes on both H1 and H3 than infected patients. These data establish a baseline for assessing polyclonal antibody responses in vaccination and infection, providing a context for future vaccine trials and emphasizing the need for further characterization of protective responses toward conserved epitopes. (201 words)IMPORTANCESeasonal influenza viruses cause hundreds of thousands of deaths each year and up to a billion infections; under the proper circumstances, influenza A viruses with pandemic potential could threaten the lives of millions more. The variable efficacies of traditional influenza virus vaccines and the desire to prevent pandemic influenzas have motivated work toward finding a universal flu vaccine. Many promising universal flu vaccine candidates currently focus on guiding immune responses to highly conserved epitopes on the central stem of the influenza hemagglutinin viral fusion protein. To support the further development of these stem-targeting vaccine candidates, in this study, we use negative stain electron microscopy to assess the prevalence of central stem-targeting antibodies in individuals who were exposed to influenza antigens through traditional vaccination and/or natural infection during the 2018–2019 flu season.

Abstract Background Cystic fibrosis (CF), through altered sodium and chloride transport across the CF transmembrane receptor (CFTR), is associated with poor mucus clearance, bacterial colonization of the lower airway, chronic pulmonary disease punctuated by acute exacerbations, and chronic inflammation. With increased use of CFTR modulators, changes in the CF pulmonary microbiome have been observed, including decreased prevalence of Pseudomonas colonization; however, overall S. aureus prevalence remains largely unchanged. An important remaining question is whether changes in the CF pulmonary microbiome, while not affecting the overall prevalence of S. aureus colonization, has led to changes in S. aureus diversity or the strain types that are most frequently recovered from children with CF. It is also unknown whether the humoral immune response to S. aureus is altered in the presence of CFTR modulator therapy. Methods Genomic DNA was extracted from S. aureus isolates obtained from two cohorts: a historic cohort, comprised of children not receiving CFTR modulators, and a modern cohort, comprised of children receiving CFTR modulator therapy. Multilocus sequence typing (MLST) and whole genome sequencing (WGS) were used to identify clonotype and characterize virulence factors of interest. Serum was obtained from participants and antibody titers to the extracellular toxins LukAB and LukED were measured. Results One hundred participants were enrolled: 50 in cohort 1 (historic) and 50 in cohort 2 (modern). Compared to cohort 1, isolates identified in cohort 2 were less likely to contain ACME and mecA; similarly, cohort 2 isolates were more likely to contain PVL, sek, and sak. The frequency of specific clonotypes changed over time, with increased prevalence of CC8 and decreased prevalence of CC1, CC5, CC15, and CC30 in cohort 2 compared to cohort 1 (Figure 1A). Serum antibody concentrations to LukAB, a conserved toxin across S. aureus, were similar across cohorts (Figure 1B). Conclusion Over time, the clonotypes responsible for S. aureus colonization in patients receiving CFTR modulators have changed. Despite changes in clonotypes and receipt of CFTR modulators, serum concentrations of LukAB-specific antibodies did not differ. These data suggest that staphylococcal colonization in patients with CF is dynamic over time and may be modified based on the receipt of CFTR modulator therapy. Figure 1. (A) S. aureus clonal complexes, over time, demonstrating a relative increase in CC8 between 2012 and 2022; (B) serum concentrations of LukAB antibodies from 2012 (historic) and 2022 (modern) cohorts. No significant difference was observed in median anti-LukAB concentrations.

ABSTRACT 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.

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 2 doses of inactivated influenza A/H5N1 vaccine alone (IIV) or with AS03 adjuvant (IIV-AS03) 1 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 postvaccination 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.Clinical Trials Registration NCT01573312. Following AS03-adjuvanted influenza A/H5N1 vaccine, enrichment of tryptophan, tyrosine, and nicotinate metabolism pathways was associated with serologic response. More specifically, increased urine abundance of benzoate-metabolism-related 4-vinylphenol sulfate on day 1 postvaccination was highly associated with serologic response.

Background: Respiratory syncytial virus (RSV) is a major cause of respiratory disease in infants, making vaccination an attractive preventive strategy. Due to earlier reports of vaccine-enhanced disease in RSV-naive children, assessing prior RSV infection is critical for determining eligibility for future infant vaccine trials. However, this is complicated by the presence of maternally transferred maternal antibodies. We sought to develop assays that measure immune responses to RSV pre-fusion (F) protein that discriminates between maternal and infant responses. Methods: We measured RSV-specific responses in two groups of children <3 years of age; those with laboratory-confirmed RSV (RSV-infected) and those enrolled prior to their first RSV season (RSV-uninfected). Serial blood samples were obtained and recent infections with RSV and other respiratory viruses were assessed during follow-up. An RSV pre-F-specific kinetic enzyme-linked immunosorbent assay (kELISA) and an F-specific reactive B cell frequency (RBF) assay were developed. Results: One hundred two young children were enrolled between July 2015 and April 2017; 74 were in the RSV-uninfected group and 28 were in the RSV-infected group. Participants were asked to provide sequential blood samples over time, but only 53 participants in the RSV-uninfected group and 22 participants in the RSV-infected groups provided multiple samples. In the RSVinfected group, most had positive kELISA and RBF during the study. In the RSV-uninfected group, two patterns emerged: declining kELISA values without reactive B cells, due to maternal transplacental antibody transfer, and persistently positive kELISA with reactive B cells, due to asymptomatic undiagnosed RSV infection. Conclusions: A kELISA targeting RSV pre-F epitopes and an RBF assay targeting RSV F-specific B cells generally allow discrimination between maternally and infant-derived antibodies.

BACKGROUND:Convalescent plasma has been one of the most common treatments for COVID-19, but most clinical trial data to date have not supported its efficacy. RESEARCH QUESTION:Is rigorously selected COVID-19 convalescent plasma with neutralizing anti-SARS-CoV-2 antibodies an efficacious treatment for adults hospitalized with COVID-19? STUDY DESIGN AND METHODS:This was a multicenter, blinded, placebo-controlled randomized clinical trial among adults hospitalized with SARS-CoV-2 infection and acute respiratory symptoms for < 14 days. Enrolled patients were randomly assigned to receive one unit of COVID-19 convalescent plasma (n = 487) or placebo (n = 473). The primary outcome was clinical status (disease severity) 14 days following study infusion measured with a seven-category ordinal scale ranging from discharged from the hospital with resumption of normal activities (lowest score) to death (highest score). The primary outcome was analyzed with a multivariable ordinal regression model, with an adjusted odds ratio (aOR) < 1.0 indicating more favorable outcomes with convalescent plasma than with placebo. In secondary analyses, trial participants were stratified according to the presence of endogenous anti-SARS-CoV-2 antibodies ("serostatus") at randomization. The trial included 13 secondary efficacy outcomes, including 28-day mortality. RESULTS:Among 974 randomized patients, 960 were included in the primary analysis. Clinical status on the ordinal outcome scale at 14 days did not differ between the convalescent plasma and placebo groups in the overall population (aOR, 1.04; one-seventh support interval [1/7 SI], 0.82-1.33), in patients without endogenous antibodies (aOR, 1.15; 1/7 SI, 0.74-1.80), or in patients with endogenous antibodies (aOR, 0.96; 1/7 SI, 0.72-1.30). None of the 13 secondary efficacy outcomes were different between groups. At 28 days, 89 of 482 (18.5%) patients in the convalescent plasma group and 80 of 465 (17.2%) patients in the placebo group had died (aOR, 1.04; 1/7 SI, 0.69-1.58). INTERPRETATION:Among adults hospitalized with COVID-19, including those seronegative for anti-SARS-CoV-2 antibodies, treatment with convalescent plasma did not improve clinical outcomes. CLINICAL TRIAL REGISTRATION:ClinicalTrials.gov; No.: NCT04362176; URL: www. CLINICALTRIALS:gov.

BackgroundBPZE1 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 (VaxINatorTM) at two dose levels.MethodsFifty 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.ResultsAcross 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.DiscussionLyophilized 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.

The role of T cell immunity has been acknowledged in recent vaccine development and evaluation. We tested the humoral and cellular immune responses to Flucelvax®, a quadrivalent inactivated seasonal influenza vaccine containing two influenza A (H1N1 Singapore/GP1908/2015 IVR-180 and H3N2 North Carolina/04/2016) and two influenza B (Iowa/06/2017 and Singapore/INFTT-16-0610/2016) virus strains, using peripheral blood mononuclear cells stimulated by pools of peptides overlapping all the individual influenza viral protein components. Baseline reactivity was detected against all four strains both at the level of CD4 and CD8 responses and targeting different proteins. CD4 T cell reactivity was mostly directed to HA/NA proteins in influenza B strains, and NP/M1/M2/NS1/NEP proteins in the case of the Influenza A strains. CD8 responses to both influenza A and B viruses preferentially targeted the more conserved core viral proteins. Following vaccination, both CD4 and CD8 responses against the various influenza antigens were increased in day 15 to day 91 post vaccination period, and maintained a Th1 polarized profile. Importantly, no vaccine interference was detected, with the increased responses balanced across all four included viral strains for both CD4 and CD8 T cells, and targeting HA and multiple additional viral antigens.

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.

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.

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, andmild 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.

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 detailed understanding of the adaptive host response to SARS-CoV-2 infection in humans is urgently needed, as questions abound regarding serologic responses and the development of antibody-mediated immunity against COVID-19. We developed a highly sensitive, high-throughput, and efficient assay using liquid bead array technology. We observed advantages over traditional indirect ELISA for the detection and quantification of binding IgG against the receptor binding domain (RBD) of SARS-CoV-2. Using this sensitive and highly reproducible assay, we sought to determine whether the severity of COVID-19 symptoms is correlated with SARS-CoV-2 binding IgG level. We measured SARS-CoV-2 RBD IgG levels from 67 subjects who had recovered from PCR-confirmed, symptomatic COVID-19. Samples were obtained approximately 6 weeks post-symptom onset. We found that COVID-19 symptom severity, assessed on an 8-point severity scale, strongly correlated with RBD IgG level (p<0.001), with and without adjustment for covariates of age, sex, and time from symptom onset. 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 as a therapeutic, and other scenarios where antibody level, rather than mere presence or absence, is relevant.

BACKGROUND:Solid organ transplant recipients are at increased risk for reactivation of herpes zoster, or shingles, and have a higher frequency of serious complications including post-herpetic neuralgia. A live, attenuated shingles vaccine is effective and approved for individuals 50 years and older. The vaccine is contraindicated following transplantation, but may be used in patients with renal failure. Utilization of the vaccine has been poor in patients with end-stage renal disease, including those awaiting transplant, owing to concerns for safety, efficacy, and potential sensitization prior to transplant.METHODS:We conducted a phase I, randomized, placebo-controlled study of the safety and immunogenicity of live, attenuated Oka strain shingles vaccine in subjects prior to or awaiting renal transplant at 3 US centers. Subjects received vaccine a minimum of 4 weeks prior to transplant.RESULTS:The vaccine was safe and well-tolerated. There were no cases of herpes zoster or rash illness. There was no change in donor-specific antibody or calculated panel reactive antibody after vaccination during the follow-up period. There were no rejection episodes. There was a significant 2.1-fold rise in geometric mean titer of anti-VZV antibody at 5 weeks post-vaccine.CONCLUSIONS:The data suggest that the shingles vaccine is safe in subjects with ESRD awaiting transplant. Antibody responses were similar to those seen previously in adults >50 years of age and are consistent with a protective response.

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. (C) 2018 Published by Elsevier Ltd.

Background: Infants are at greatest risk for pertussis morbidity and mortality. Maternal vaccination during pregnancy has been shown to prevent pertussis in young infants in high-and middle-income countries. However, data on the levels of maternal pertussis antibodies and the efficiency of transplacental transfer in low-income South Asian settings are limited. Objective: To estimate the prevalence of maternal pertussis antibodies and the efficiency of transplacental transfer in rural southern Nepal. Design/methods: Paired maternal-infant blood samples were collected from a subsample of participants in a randomized, controlled trial of maternal influenza immunization (n = 291 pairs). Sera were tested by enzyme-linked immunosorbent assays for pertussis toxin, filamentous hemagglutinin, pertactin, and fimbriae. Maternal and infant pertussis antibody levels and transplacental transfer efficiency were determined and potential factors associated with both were assessed. Results: Elevated maternal antibodies to pertussis toxin, suggesting recent pertussis infection, were rarely detected (4%, tested n = 305). However, paired maternal-cord sera were highly correlated across all antibodies; transplacental antibody transfer ratios for pertussis toxin were 1.14 (n = 291, 95% CI 1.07-1.20); filamentous hemagglutinin 1.10 (n = 120, 95% CI: 1.01-1.20); fimbriae 2/3 1.05 (n = 120, 95% CI: 0.96-1.15) and pertactin 0.96 (n = 289, 95% CI: 0.91-1.00). Older gestational age was associated with increased pertussis toxin and decreased fimbriae 2/3 antibody transport. Conclusions: A low prevalence of maternal antibody to all four pertussis antigens was noted in Nepal, but transplacental antibody transfer was efficient. No consistent demographic factors were associated with elevated maternal antibody levels or efficiency of transplacental transfer. If an increase in infant pertussis disease burden was detected in this population, maternal immunization could be an effective intervention to prevent disease in early infancy. (C) 2017 The Author(s). Published by Elsevier Ltd.

Acute graft-versus-host disease (aGvHD) is an unpredictable immunological complication that affects the skin, gut, or liver following allogeneic hematopoietic cell transplantation (HCT). Donor Th1 cells can initiate aGvHD after recognition of recipient alloantigens and migration to target tissues via homing receptors.1 Paradoxically, experiments in animal models of transplantation suggest that deficiency of the inflammatory Th1 cytokine IFN-γ can exacerbate aGvHD severity and mortality.2,3 Investigators have interpreted these results to mean that other cell types are capable of generating aGvHD or that loss of a protective function related to IFN-γ was responsible for the intensified alloreactivity observed in these animal models.