Serum Antibody Responses Research Articles

Antibody responses of healthy adults to the p27 peptide of respiratory syncytial virus fusion protein

The respiratory syncytial virus (RSV) fusion (F) protein undergoes two furin-cleavage events to become fusion competent, resulting in the release of a twenty-seven amino acid peptide (p27). Recent studies indicate that the p27 region of the F protein was an immunodominant antigen in young children. In this study, we evaluated the kinetics of the serum antibody response to the p27 peptide following natural RSV reinfection in adults. Nineteen healthy adults under sixty-five years of age were enrolled during the 2018–2019 RSV season in Houston, TX. Blood was collected at three study visits and RSV infection status was defined by changes in neutralizing antibody resulting in three groups: uninfected (n = 12), acutely infected (n = 4), and recently infected (n = 3). Serum IgG and IgA antibodies against RSV/A and RSV/B p27 peptides were measured by enzyme-linked immunosorbent assays, and serum p27-like antibodies were detected by a p27 competitive antibody assay. Anti-p27 antibodies were detected in all subjects at each study visit. The measured IgG and IgA anti-p27 antibody levels followed the same pattern as other RSV site-specific and neutralizing antibody responses described for this cohort previously: the uninfected group had stable responses for the duration of the study period, the acutely infected group had a significant increase following RSV infection, and the recently infected group had a decrease in anti-p27 antibody during the study period. These results indicate that antibodies to the p27 region of the F protein are generated following natural RSV reinfection and suggest that some of the F protein is potentially in a partially cleaved state on the surface of virions, expanding on the previous assumption that all of p27 is post-translationally released and not present on mature F. Additionally, antibody responses were significantly lower (1.4–1.5-fold) toward RSV/B than to RSV/A p27 at each study visit, despite being an RSV/B dominant outbreak. Understanding the mechanism for the differences in the magnitude of the RSV/A and RSV/B p27 antibody response may enhance our understanding of the intracellular processing of the F protein.

Analysis of B Cell Receptor Repertoires Reveals Key Signatures of the Systemic B Cell Response after SARS-CoV-2 Infection.

ABSTRACTA comprehensive study of the B cell response against SARS-CoV-2 could be significant for understanding the immune response and developing therapeutical antibodies and vaccines. To define the dynamics and characteristics of the antibody repertoire following SARS-CoV-2 infection, we analyzed the mRNA transcripts of immunoglobulin heavy chain (IgH) repertoires of 24 peripheral blood samples collected between 3 and 111 days after symptom onset from 10 COVID-19 patients. Massive clonal expansion of naive B cells with limited somatic hypermutation (SHM) was observed in the second week after symptom onset. The proportion of low-SHM IgG clones strongly correlated with spike-specific IgG antibody titers, highlighting the significant activation of naive B cells in response to a novel virus infection. The antibody isotype switching landscape showed a transient IgA surge in the first week after symptom onset, followed by a sustained IgG elevation that lasted for at least 3 months. SARS-CoV-2 infection elicited poly-germ line reactive antibody responses. Interestingly, 17 different IGHV germ line genes recombined with IGHJ6 showed significant clonal expansion. By comparing the IgH repertoires that we sequenced with the 774 reported SARS-CoV-2–reactive monoclonal antibodies (MAbs), 13 shared spike-specific IgH clusters were found. These shared spike-specific IgH clusters are derived from the same lineage of several recently published neutralizing MAbs, including CC12.1, CC12.3, C102, REGN10977, and 4A8. Furthermore, identical spike-specific IgH sequences were found in different COVID-19 patients, suggesting a highly convergent antibody response to SARS-CoV-2. Our analysis based on sequencing antibody repertoires from different individuals revealed key signatures of the systemic B cell response induced by SARS-CoV-2 infection.IMPORTANCE Although the canonical delineation of serum antibody responses following SARS-CoV-2 infection has been well established, the dynamics of antibody repertoire at the mRNA transcriptional level has not been well understood, especially the correlation between serum antibody titers and the antibody mRNA transcripts. In this study, we analyzed the IgH transcripts and characterized the B cell clonal expansion and differentiation, isotype switching, and somatic hypermutation in COVID-19 patients. This study provided insights at the repertoire level for the B cell response after SARS-CoV-2 infection.

584. Phase 1 Placebo-Controlled Trial of COVI-VAC™, an Intranasal, Live Attenuated COVID-19 Vaccine

BackgroundCOVI-VACTM is an intra-nasal live-attenuated SARS-COV-2 synthetic viral vaccine being developed for the prevention of COVID-19. COVI-VAC is attenuated through deletion of the furin cleavage site and introduction of 283 silent deoptimizing mutations that maintain viral amino acid sequence but result in significant attenuation due to slow translation in the human host cell. Notably, COVI-VAC includes all viral antigens and is not limited to spike. COVI-VAC has demonstrated attenuation, immunogenicity and single dose protection in both Syrian golden hamster and non-human primate models.Methods48 healthy young adults were enrolled in an inpatient quarantine setting to one of 3 dose escalating cohorts and randomized to COVI-VAC or saline placebo given as nose drops, as a single 0.5mL dose or 2 doses 28 days apart. Endpoints included solicited and unsolicited adverse events, serum cytokines, viral shedding and sequence stability, mucosal and serum antibody responses and IFN ELISpot. Subjects will be followed for 1 year for late safety events and durability of immune response.ResultsDosing is complete. There has been no trend in solicited reactogenicity events, and all unsolicited adverse events reported to date have been mild. There have been no SAEs or Grade 3 or 4 events. Vaccine virus from anonymized subjects was shed at levels lower than that likely to result in onward transmission, and the deoptimized sequence of the shed virus remained unchanged compared to the original vaccine sequence. Unblinded data including immunogenicity will be available prior to the IDWeek meeting. ConclusionCOVI-VAC appears safe and well tolerated in healthy young adults. Vaccination resulted in minimal viral shedding without sequence instability. Safety and shedding data supports continued development in a wider Phase 2/3 population. Disclosures Sybil Tasker, MD, MPH, FIDSA, Codagenix Inc (Employee, Shareholder) Daryl Bendel, MD, Codagenix Inc (Scientific Research Study Investigator) Melissa Bevan, MD, Codagenix Inc (Scientific Research Study Investigator) Steffen Mueller, PhD, Codagenix Inc (Board Member, Employee, Shareholder) Anna Kushnir, PHD, Codagenix Inc (Employee) Brandon Londt, PhD, Codagenix Inc (Other Financial or Material Support, contracted lab services) J. Robert Coleman, PhD, Codagenix Inc. (Board Member, Employee, Shareholder)

A Field Study Evaluating Humoral Immunity in Calves Vaccinated with Multivalent Bovine Respiratory Pathogen Vaccines

Abstract Bovine Respiratory Syncytial Virus (BRSV), Bovine Parainfluenza 3 (BPI3) and Mannheimia haemolytica (Mh) are major respiratory pathogens in the bovine respiratory disease complex. It is important to optimize passive and active immunity to these pathogens early in life to reduce clinical and subclinical productivity losses. The administration of inactivated, adjuvanted and multivalent vaccines, such as Bovilis® Bovipast RSP (Bovipast), and Bovalto® Respi 3 (Bovalto) to calves, may enhance cellular and humoral immunity against BRSV, BPI3 and Mh. A field trial evaluated the immune responses to these three agents in the first year of life in 12 Bovipast and 13 Bovalto vaccinated calves, and 5 negative control calves. Calves were vaccinated starting at 2 weeks of age and revaccinated 4 weeks later (primo vaccination). A booster vaccination was given at approximately 10 months of age. Serum samples were taken at time intervals up to 6 months after primo vaccination and up to 1 month after the booster vaccination. BRSV serum titres were evaluated using a serum neutralisation assay (SN), and BRSV, BPI3 and Mh titres were evaluated using a commercial enzyme linked immunosorbent assay (ELISA) test. Serum antibodies after primo and booster vaccinations in the individual calves were evaluated by calculating the areas under the curve (AUC) of the Log2 transformed BRSV SN titres and the optic density measures of the ELISA tests for BRSV, BPI3 and Mh. Multivariate general linear models were used to evaluate the influence of the vaccination on the AUC of the serum measures within 6 months after the primo vaccination. Similarly, models evaluated the AUC of the serum measures after the booster vaccination. The Bovipast vaccinated calves had significantly higher SN and ELISA titres AUC following the primo vaccination and booster vaccinations compared to the negative control calves and the Bovalto vaccinated calves. The Bovalto vaccinated calves did not have a significantly different BRSV SN and ELISA titres AUC response after the primo or booster vaccinations compared to the negative control calves. The serum antibody responses to BPI3 and Mh in the vaccinated calves were less pronounced than the Bovipast BRSV antibody response. Bovipast and Boval- to vaccinated calves mounted a significantly higher AUC ELISA OD for both BPI3 and Mh and the highest AUC was measured in the Bovipast vaccinated calves. This study indicated that early vaccinations of calves with multivalent adjuvanted inactivated BRD vaccines, such as Bovilis® Bovipast RSP can elicit a humoral response with a cellular-mediated memory effect as indicated by the booster vaccination.

Safety and Immunogenicity of M2-Deficient, Single Replication, Live Influenza Vaccine (M2SR) in Adults.

M2SR (M2-deficient single replication) is an investigational live intranasal vaccine that protects against multiple influenza A subtypes in influenza-naïve and previously infected ferrets. We conducted a phase 1, first-in-human, randomized, dose-escalation, placebo-controlled study of M2SR safety and immunogenicity. Adult subjects received a single intranasal administration with either placebo or one of three M2SR dose levels (106, 107 or 108 tissue culture infectious dose (TCID50)) expressing hemagglutinin and neuraminidase from A/Brisbane/10/2007 (H3N2) (24 subjects per group). Subjects were evaluated for virus replication, local and systemic reactions, adverse events (AE), and immune responses post-vaccination. Infectious virus was not detected in nasal swabs from vaccinated subjects. At least one AE (most commonly mild nasal rhinorrhea/congestion) was reported among 29%, 58%, and 83% of M2SR subjects administered a low, medium or high dose, respectively, and among 46% of placebo subjects. No subject had fever or a severe reaction to the vaccine. Influenza-specific serum and mucosal antibody responses and B- and T-cell responses were significantly more frequent among vaccinated subjects vs. placebo recipients. The M2SR vaccine was safe and well tolerated and generated dose-dependent durable serum antibody responses against diverse H3N2 influenza strains. M2SR demonstrated a multi-faceted immune response in seronegative and seropositive subjects.

Serum Antibody Response Comparison and Adverse Reaction Analysis in Healthcare Workers Vaccinated with the BNT162b2 or ChAdOx1 COVID-19 Vaccine.

The COVID-19 pandemic is changing rapidly and requires different strategies to maintain immunization. In Korea, different COVID-19 vaccines are recommended and available for various populations, including healthcare workers (HCWs) at high risk of SARS-CoV-2 infection. We plan to evaluate the adverse events (AEs) and immunogenicity of the BNT162b2 and ChAdOx1 vaccines in HCWs at a single center. This cohort study included HCWs fully vaccinated with either BNT162b2 or ChAdOx1. Blood samples were taken eight weeks after the second vaccination with both COVID-19 vaccines and six months after the second vaccination from participants with the BNT162b2 vaccine. The primary endpoint for immunogenicity was the serum neutralizing antibody responses eight weeks after vaccination. The secondary endpoint was the incidence of various AEs within 28 days of each vaccination. Between 16 March and 23 June 2021, 115 participants were enrolled (65 in the ChAdOx1 group and 50 in the BNT162b2 group). Significantly higher surrogate virus neutralization test (sVNT) inhibition was observed in participants vaccinated with two doses of BNT162b2 (mean (SD) 91.4 (9.68)%) than in those vaccinated with ChAdOx1 (mean (SD) 73.3 (22.57)%). The effectiveness of the BNT162b2 vaccine was maintained across all age and gender categories. At six months after the second dose, serum antibody levels declined significantly in the BNT162b2 group. The main adverse events, including fever, myalgia, fatigue, and headache, were significantly higher in the ChAdOx1 group after the first dose, whereas, after the second dose, those AEs were significantly higher in the BNT162b2 group (p < 0.05). Two doses of either the ChAdOx1 or the BNT162b2 COVID-19 vaccine resulted in very high seropositivity among the HCWs at our center. The quality of the antibody response, measured by sVNT inhibition, was significantly better with the BNT162b2 vaccine than with the ChAdOx1 vaccine. There was no significant association between neutralizing antibody response and AE after each vaccination in our cohort.

Reduced antibody activity against SARS-CoV-2 B.1.617.2 delta virus in serum of mRNA-vaccinated individuals receiving tumor necrosis factor-α inhibitors

BackgroundAlthough vaccines effectively prevent coronavirus disease 2019 (COVID-19) in healthy individuals, they appear to be less immunogenic in individuals with chronic inflammatory disease (CID) or receiving chronic immunosuppression therapy.MethodsHere we assessed a cohort of 77 individuals with CID treated as monotherapy with chronic immunosuppressive drugs for antibody responses in serum against historical and variant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viruses after immunization with the BNT162b2 mRNA vaccine.FindingsLongitudinal analysis showed the greatest reductions in neutralizing antibodies and Fc effector function capacity in individuals treated with tumor necrosis factor alpha (TNF-α) inhibitors (TNFi), and this pattern appeared to be worse against the B.1.617.2 delta virus. Within 5 months of vaccination, serum neutralizing titers of all TNFi-treated individuals tested fell below the presumed threshold correlate for antibody-mediated protection. However, TNFi-treated individuals receiving a third mRNA vaccine dose boosted their serum neutralizing antibody titers by more than 16-fold.ConclusionsVaccine boosting or administration of long-acting prophylaxis (e.g., monoclonal antibodies) will likely be required to prevent SARS-CoV-2 infection in this susceptible population.FundingThis study was supported by grants and contracts from the NIH (R01 AI157155, R01AI151178, and HHSN75N93019C00074; NIAID Centers of Excellence for Influenza Research and Response (CEIRR) contracts HHSN272201400008C and 75N93021C00014; and Collaborative Influenza Vaccine Innovation Centers [CIVIC] contract 75N93019C00051).

Serum antibody response in patients with philadelphia-chromosome positive or negative myeloproliferative neoplasms following vaccination with SARS-CoV-2 spike protein messenger RNA (mRNA) vaccines.

Serum antibody response in patients with philadelphia-chromosome positive or negative myeloproliferative neoplasms following vaccination with SARS-CoV-2 spike protein messenger RNA (mRNA) vaccines.

BNT162b2 mRNA vaccine elicited antibody response in blood and milk of breastfeeding women

The importance of breastmilk in postnatal life lies in the strong association between breastfeeding and the reduction in the risk of infection and infection-related infant mortality. However, data regarding the induction and dynamics of breastmilk antibodies following administration of the Pfizer-BioNTech BNT162b2 COVID-19 mRNA vaccine is scarce, as pregnant and lactating women were not included in the initial vaccine clinical trials. Here, we investigate the dynamics of the vaccine-specific antibody response in breastmilk and serum in a prospective cohort of ten lactating women who received two doses of the mRNA vaccine. We show that the antibody response is rapid and highly synchronized between breastmilk and serum, reaching stabilization 14 days after the second dose. The response in breastmilk includes both IgG and IgA with neutralization capacity.

Comparative study on antigen persistence and immunoprotective efficacy of intramuscular and intraperitoneal injections of squalene – aluminium hydroxide (Sq + Al) adjuvanted viral hemorrhagic septicaemia virus vaccine in olive flounder (Paralichthys olivaceus)

The profitability of the olive flounder (Paralichthys olivaceus) aquaculture industry in Korea depends on high production and maintenance of flesh quality, as consumers prefer to eat raw flounders from aquaria and relish the raw muscles as ‘sashimi’. For sustaining high production, easy-to-deliver and efficient vaccination strategies against serious pathogens, such as viral hemorrhagic septicemia virus (VHSV), is very important as it cause considerable losses to the industry. Whereas, a safe and non-invasive vaccine formulation that is free from unacceptable side-effects and does not devalue the fish is needed to maintain flesh quality. We previously developed a squalene–aluminium hydroxide (Sq + Al) adjuvanted VHSV vaccine that conferred moderate to high protection in flounder, without causing any side effects when administered through the intraperitoneal (IP) injection route. However, farmers often demand intramuscular (IM) injection vaccines as they are relatively easy to administer in small fishes. Therefore, we administered the developed vaccine via IP and IM routes and investigated the safety and persistency of the vaccine at the injection site. In addition, we conducted a comparative analysis of vaccine efficacy and serum antibody response. The clinical and histological observation of the IM and IP groups showed that our vaccine remained persistence at the injection sites for 10–17 weeks post vaccination (wpv), without causing any adverse effects to the fish. The relative percentage of survival were 100% and 71.4% for the IP group and 88.9% and 92.3% for the IM group at 3 and 17 wpv, respectively. Thus, considering the persistency period (24 wpv) and both short and long-term efficacy of our vaccine, the present study offers an option to flounder farmers in selecting either IM or IP delivery strategy according to their cultured fish size and harvesting schedule — IM vaccination for small-sized fish and IP vaccination for table-sized fish.

Breast Implants and Breast Cancer Immunosurveillance: An Updated Analysis of Serum Antibody Responses to Breast Cancer Antigen Post Implant Placement

Breast Implants and Breast Cancer Immunosurveillance: An Updated Analysis of Serum Antibody Responses to Breast Cancer Antigen Post Implant Placement

Longitudinal field survey during deployment of an emergency autogenous vaccine against Betanodavirus in farmed giant grouper (Epinephelus lanceolatus): Multiple factors contribute to outbreaks and survival

Betanodavirus or nervous necrosis virus (NNV) continues to pose a formidable threat to aquaculture worldwide, with a widening host range and outbreaks incurring significant mortalities in both hatchery and grow-out phases. In Australia, several fish species with high susceptibility to the Red Grouper Nervous Necrosis Virus (RGNNV) genotype are intensively farmed, including barramundi (Lates calcarifer) and giant grouper (Epinephelus lanceolatus). In response to a major outbreak of viral encephalopathy and retinopathy (VER) in grow-out of E. lanceolatus on a farm in Southeast Queensland, we developed an autogenous protein subunit vaccine by cloning the nucleocapsid protein gene sequence into established platform technology already in use for veterinary vaccines in Australia. The experimental vaccine was deployed under a research use permit as a cold-formalin inactivated lysate of E.coli over-expressing the capsid protein, emulsified in the oil adjuvant Montanide ISA763A VG and delivered by intraperitoneal injection. We report longitudinal farm data over three grow-out batches of grouper before and during vaccine deployment. Monthly sampling was conducted for pathology, viral detection and serum antibody response post-deployment. We found no adverse reaction to the vaccine, with melanised encapsulated vaccine emulsion confined to the mesenteric fat, which dispersed over time. An outbreak of disease due to NNV occurred during deployment but was rapidly brought under control. Coupled with specific antibody response detected in vaccinated fish during grow-out, the vaccine appeared to be useful in managing VER on the farm. Water quality data, pathology and the dynamics of infection and mortalities, indicate the critical role environmental and dietary factors play in outbreaks of Betanodavirus. The study is illustrative of the multifactorial nature of disease outbreaks in complex commercial farm operations, the value of veterinary oversight and the usefulness of relatively simple and swiftly deployed autogenous vaccine platforms.

Evaluation of Cell-Penetrating Peptides as Mucosal Immune Enhancers for Nasal Vaccination.

Cell-penetrating peptides (CPPs) have been evaluated as enhancers in drug delivery, their addition in medical formulations favors drug absorption allowing obtaining the pharmacological effect with lower doses. In vaccine formulations their inclusion has been also explored with interesting results. Currently mucosal vaccination constitutes a promising alternative with the main advantage of inducing both systemic and mucosal immune responses, which are crucial for control tumors and infections at mucosal tissues. In the present work the nasal immune-enhancing effect of four CPPs was evaluated in Balb/c mice. Animals were intranasally immunized with CPP and the recombinant hepatitis B surface protein (HBsAg) as model antigen. The antibody response in sera and mucosal tissue was measured by ELISA. The IFN-γ secretion response at spleen was also evaluated by ELISPOT and ELISA. Among the CPPs studied one novel peptide stand out by its ability to potentiate the humoral and cellular immune response against the co-administered antigen. Considering that the use of mucosal routes is a promising strategy in vaccination, which are gaining special relevance nowadays in the development of novel candidates against SARS-CoV-2 and other potential emerging respiratory virus, the searching and development of safe mucosal adjuvants constitute a current need.Graphic

Antigen-specific tolerization in human autoimmunity: Inhibition of interferon-beta1a anti-drug antibodies in multiple sclerosis: A case report

Background: Antigen-specific tolerance in auto-immune diseases is the goal for effective treatment with minimal side-effects. Whilst this is achievable in animal models, notably via intravenous delivery of the model-specific autoantigen following transient CD4 T cell depletion, specific multiple sclerosis autoantigens remain unproven. However, anti-drug antibodies to human therapeutic proteins represent a model human autoimmune condition, which may be used to examine immune-tolerance induction. Some people with MS (PwMS) on interferon-beta1a (IFNβ1a) develop neutralizing antibodies to IFNβ1a that do not disappear in repeated tests over years.Methods: One PwMS was recruited, as part of a planned phase IIa trial (n = 15), who had developed neutralizing antibodies to subcutaneous IFNβ1a. Mitoxantrone (12 mg/m2) was administered as a lymphocyte depleting agent followed by four days of (88 μg/day + three 132 μg/day) intravenous IFNβ1a. Subcutaneous IFNβ1a three times a week was maintained during follow-up. IFNβ1a neutralizing antibody responses in serum were measured during treatment and three-monthly for 12 months.Findings: One participant was recruited and, within 6 months of tolerization, the neutralizing antibodies were undetectable. The tolerization treatment was well tolerated. However, the study was terminated after the first enrolment, on ethical grounds, as treatment alternatives became available and the potential risks of mitoxantrone use increased.Interpretation: The data suggest that it may be possible to induce antigen-specific tolerance by providing tolerogenic antigen following transient immune depletion. Further studies are warranted.Funding: The study was supported by an unrestricted research grant from Merck-Serono.

Serum antibody response against periodontal bacteria and coronary heart disease: Systematic review and meta‐analysis

The present systematic review and meta-analysis assessed the strength of a reported association between elevated serum anti-periodontal bacterial antibody responses and coronary heart disease (CHD). Twenty original studies were identified after systematically searching five databases. The majority (n= 11) compared serum anti-Porphyromonas gingivalis (Pg) and/or anti-Aggregatibacter actinomycetemcomitans (Aa) IgG antibody responses between CHD patients and control participants. The strength of the association between serum anti-Pg antibodies and CHD (n= 10) and serum anti-Aa antibodies and CHD (n= 6) was investigated using a meta-analysis approach separately. Most studies (61%) reported that the serum IgG antibody responses were elevated in CHD patients than in controls. The meta-analyses showed a significant association between elevated serum IgG antibody responses (anti-Pg and anti-Aa) and CHD, with pooled odds ratios of 1.23 [95% confidence interval (CI): 1.09-1.38, p= .001] and 1.25 (95% CI: 1.04-1.47, p= .0004), respectively. A modest increase of CHD events in individuals with higher serum anti-Pg and anti-Aa IgG antibody responses may support their use as potential biomarkers to detect and monitor at-risk populations. However, the observed inconsistencies with the design and interpretation of immunoassays warrant standardization of the immunoassays assessing antibody responses against periodontal bacteria.

SARS-CoV-2 mucosal antibody development and persistence and their relation to viral load and COVID-19 symptoms

Although serological studies have shown that antibodies against SARS-CoV-2 play an important role in protection against (re)infection, the dynamics of mucosal antibodies during primary infection and their potential impact on viral load and the resolution of disease symptoms remain unclear. During the first pandemic wave, we assessed the longitudinal nasal antibody response in index cases with mild COVID-19 and their household contacts. Nasal and serum antibody responses were analysed for up to nine months. Higher nasal receptor binding domain and spike protein-specific antibody levels at study inclusion were associated with lower viral load. Older age was correlated with more frequent COVID-19 related symptoms. Receptor binding domain and spike protein-specific mucosal antibodies were associated with the resolution of systemic, but not respiratory symptoms. Finally, receptor binding domain and spike protein-specific mucosal antibodies remained elevated up to nine months after symptom onset.

Effect of maternal separation and transportation stress on the bovine upper respiratory tract microbiome and the immune response to resident opportunistic pathogens

BackgroundThe bovine upper respiratory tract (URT) microbiome includes opportunistic pathogens that cause respiratory disease and stress associated with maternal separation and transportation contributes to the severity of this respiratory disease. Stress is known to alter the gut microbiome but little is known regarding the effect of stress on the URT microbiota. This study used six-month old suckling beef calves to investigate whether maternal separation (weaned), by itself or combined with transportation (weaned + transport), altered the URT microbiome and host immune responses to resident opportunistic pathogens.ResultsTaxonomic and functional composition of the URT microbiome in suckling and weaned beef calves did not change significantly when serially sampled over a one-month period. Subtle temporal changes in the URT microbiome composition were observed in weaned + transport calves. Total bacterial density was lower (p < 0.05) on day 4 post-weaning in both the weaned and weaned + transport groups when compared to suckling calves. In addition, significant (p < 0.05) temporal changes in the density of the opportunistic pathogens, M. haemolytica and P. multocida, were observed independent of treatment but these changes did not correlate with significantly increased (p < 0.05) serum antibody responses to both of these bacteria in the weaned and weaned + transport groups. Serum antibody responses to My. bovis, another opportunistic pathogen, remained unchanged in all treatment groups. Weaning, by itself and in combination with transportation, also had significant (p < 0.05) short- (2 to 8 days post-weaning) and long-term (28 days post-weaning) effects on the expression of adrenergic receptor genes in blood leukocytes when compared to age-matched suckling beef calves.ConclusionsMaternal separation (weaning) and transportation has minor effects on the taxonomic and functional composition of the URT microbiome and temporal changes in the density of opportunistic pathogen residing in the URT did not correlate with significant changes in immune responses to these bacteria. Significant changes in adrenergic receptor expression in blood leukocytes following weaning, with or without transportation, suggests altered neuroimmune regulation should be further investigated as a mechanism by which stress can alter host-microbiome interactions for some opportunistic respiratory pathogens that reside in the URT.

Antibodies to Seasonal Coronaviruses Rarely Cross-React With SARS-CoV-2: Findings From an African Birth Cohort.

Antibodies to seasonal human-coronaviruses (sHCoV) may cross-protect against SARS-CoV-2. We investigated antibody responses in biobanked serum obtained before the pandemic from infants with polymerase chain reaction-confirmed sHCoV. Among 141 samples with antibodies to sHCoV, 4 (2.8%) were positive for SARS-CoV-2-S1 and 8 (5.7%) for SARS-CoV-2-S2. Antibodies to sHCoV rarely cross-react with SARS-CoV-2 antigens and are unlikely to account for mild pediatric illness.

COVID-19 mRNA vaccine and antibody response in lactating women: a prospective cohort study

BackgroundImmunological protection via breastfeeding is well known. The immunological profile of human milk changes during lactation. No clinical trials have been conducted in lactating women with the newest mRNA vaccines against SARS- CoV-2. A Few studies have shown the presence of antibodies in breastmilk after vaccination. The aim of this work is to study possible antibodies transfer via breastmilk and also the immunological characteristics of lactating women compared to non-lactating women, after using the BNT162b2 Pfizer vaccine.MethodsThis is a prospective cohort study with a convenience homogenous sample of 24 healthcare workers (14 lactating and 10 non-lactating women) enrolled at the time of COVID-19 vaccination. Clinical data was registered in a questionnaire. Titers of SARS-CoV-2 spike IgG, IgA and IgM were quantified in post vaccination blood and human milk. Antibody quantification was performed by an in-house ELISA to SARS-CoV-2 trimeric spike protein.ResultsAll women showed immunity after vaccination with positive antibodies for IgM, IgA and IgG antibodies. The dominant serum antibody response was IgG. Modest levels of antibodies in breastmilk of lactating mothers were observed in this study, especially IgG in 42.9%. There was a moderate association between higher titers of IgG and a longer duration of breastfeeding (R= 0.55, p=0.041).ConclusionsEvidence of antibody transfer in human milk after COVID-19 vaccination is scarce. The presence of antibodies in human milk is reported, but immunization through breastfeeding is still to be established.

A Multiplex Noninvasive Salivary Antibody Assay for SARS-CoV-2 Infection and Its Application in a Population-Based Survey by Mail.

ABSTRACTNoninvasive salivary antibody immunoassays can enable low-cost epidemiological surveillance of infections. This study involved developing and validating a multiplex suspension immunoassay on the Luminex platform to measure immunoglobulin G (IgG) responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid and spike (S) proteins, and the spike protein’s S1 and S2 subunits and receptor binding domain. Multiple versions of these recombinant proteins acquired from commercial and noncommercial sources were evaluated. Assay development and validation utilized saliva and serum samples from coronavirus disease 2019 (COVID-19) cases procured from commercial sources and negative controls from a prepandemic survey. Saliva was also collected in a demonstration survey by mail involving adult individuals in the United States who were diagnosed with SARS-CoV-2 infection 15 to 80 days prior to sample collection. The survey had an 83% valid sample return rate (192 samples from 38 states). Most COVID-19 cases (93%) reported mildly symptomatic or asymptomatic infections. The final salivary assay based on the best-performing spike and nucleocapsid proteins had a sensitivity of 87.1% (95% bootstrap confidence interval, 82.1 to 91.7%) and specificity of 98.5% (95.0 to 100%) using 227 and 285 saliva samples, respectively. The same assay had 95.9% (92.8 to 98.9%) sensitivity and 100% (98.4 to 100%) specificity in serum (174 and 285 serum samples, respectively). Salivary and serum antibody responses to spike and nucleocapsid proteins were strongly correlated in 22 paired samples (r = 0.88 and r = 0.80, respectively). Antibody responses peaked at approximately 50 days postonset; greater illness severity was associated with stronger responses. This study demonstrated that a salivary antibody assay can be used in large-scale population surveys by mail to better characterize public health impacts of COVID-19.IMPORTANCE Given the enormous impacts of the COVID-19 pandemic, developing tools for population surveillance of infection is of paramount importance. This article describes the development of a multiplex immunoassay on a Luminex platform to measure salivary immunoglobulin G responses to the spike protein, its two subunits and receptor binding domain, and the nucleocapsid protein of SARS-CoV-2. The assay validation utilized serum and saliva samples from prepandemic controls and recent COVID-19 cases. A survey by mail targeting recent COVID-19 cases across the United States also demonstrated the utility of safe, at-home self-collection of saliva. By incorporating multiple SARS-CoV-2 proteins, this assay may differentiate responses to natural SARS-CoV-2 infections from responses to most vaccines. Application of this noninvasive immunoassay in COVID-19 surveillance can help provide estimates of cumulative incidence rates of symptomatic and asymptomatic infections in various communities and subpopulations, temporal patterns of antibody responses, and risk factors for infection.