Systems serology-based comparison of antibody effector functions induced by adjuvanted vaccines to guide vaccine design

The mechanisms by which antibodies confer protection vary across vaccines, ranging from simple neutralization to functions requiring innate immune recruitment via Fc-dependent mechanisms. The role of adjuvants in shaping the maturation of antibody-effector functions remains under investigated. Using systems serology, we compared adjuvants in licensed vaccines (AS01_B/AS01_E/AS03/AS04/Alum) combined with a model antigen. Antigen-naive adults received two adjuvanted immunizations followed by late revaccination with fractional-dosed non-adjuvanted antigen ( NCT00805389 ). A dichotomy in response quantities/qualities emerged post-dose 2 between AS01_B/AS01_E/AS03 and AS04/Alum, based on four features related to immunoglobulin titers or Fc-effector functions. AS01_B/E and AS03 induced similar robust responses that were boosted upon revaccination, suggesting that memory B-cell programming by the adjuvanted vaccinations dictated responses post non-adjuvanted boost. AS04 and Alum induced weaker responses, that were dissimilar with enhanced functionalities for AS04. Distinct adjuvant classes can be leveraged to tune antibody-effector functions, where selective vaccine formulation using adjuvants with different immunological properties may direct antigen-specific antibody functions.

551 Bilateral Carpal Tunnel Syndrome Following AstraZeneca (AZD1222) COVID-19 Vaccination: A Case Report

Covid-19 infections correlate with peripheral neuropathy. Correlations extend to vaccination, with reports of polyradiculoneuropathy. We report a case of a 59-year-old right-hand dominant female presenting with bilateral carpal tunnel syndrome (CTS) nineteen days after AZD1222.

BSSH diploma-qualified hand surgeon assessment identified increasing median nerve (MN) paraesthesia and upper limb pain. Symptoms occurred post-AZD1222 second dose administered 12-weeks after the first. Past medical history was unremarkable, and she had not contracted Covid-19. Examination found severe CTS-signs: thenar weakness, positive provocative tests (Phalen's and Tinel's) and 8mm MN static 2-point discrimination. Electrophysiology confirmed very severe wrist bilateral median neuropathies, with no evidence of widespread peripheral neuropathy. Left carpal tunnel decompression found a swollen MN bulging through the transverse carpal ligament. The patient reported symptom improvement 2 weeks post-operatively.

This was reported using MHRA “yellow card” protocols as symptoms occurred within the period of neuropathic side effects. Proposed neuropathy mechanisms in Covid-19 include vasa nervorum microangiopathy. Post-vaccine effects could be connected to such changes in microcirculation implicated in CTS. Vaccines containing SARS-CoV-2 antigens enhance autoimmunity and may cause antibody-mediated effects on the synovial sheath, worsening symptoms in pre-existing CTS. Though we do not claim causality, emerging post-vaccination effects may include exacerbation. It is not uncommon for clinicians to diagnose CTS in patients with symptoms overlooked until an inciting event. With Covid-19 ‘boosters' the long-term strategy, vaccinations may increase neuropathy contribution. Increasing caseloads may present future challenges to hand surgeons managing CTS. Recording correlations may provide a basis for investigating CTS pathophysiology post AZD1222.

Mapping functional humoral correlates of protection against malaria challenge following RTS,S/AS01 vaccination

Vaccine development has the potential to be accelerated by coupling tools such as systems immunology analyses and controlled human infection models to define the protective efficacy of prospective immunogens without expensive and slow phase 2b/3 vaccine studies. Among human challenge models, controlled human malaria infection trials have long been used to evaluate candidate vaccines, and RTS,S/AS01 is the most advanced malaria vaccine candidate, reproducibly demonstrating 40 to 80% protection in human challenge studies in malaria-naïve individuals. Although antibodies are critical for protection after RTS,S/AS01 vaccination, antibody concentrations are inconsistently associated with protection across studies, and the precise mechanism(s) by which vaccine-induced antibodies provide protection remains enigmatic. Using a comprehensive systems serological profiling platform, the humoral correlates of protection against malaria were identified and validated across multiple challenge studies. Rather than antibody concentration, qualitative functional humoral features robustly predicted protection from infection across vaccine regimens. Despite the functional diversity of vaccine-induced immune responses across additional RTS,S/AS01 vaccine studies, the same antibody features, antibody-mediated phagocytosis and engagement of Fc gamma receptor 3A (FCGR3A), were able to predict protection across two additional human challenge studies. Functional validation using monoclonal antibodies confirmed the protective role of Fc-mediated antibody functions in restricting parasite infection both in vitro and in vivo, suggesting that these correlates may mechanistically contribute to parasite restriction and can be used to guide the rational design of an improved vaccine against malaria.

Comprehensive Data Integration Approach to Assess Immune Responses and Correlates of RTS,S/AS01-Mediated Protection From Malaria Infection in Controlled Human Malaria Infection Trials

RTS,S/AS01 (GSK) is the world’s first malaria vaccine. However, despite initial efficacy of almost 70% over the first 6 months of follow-up, efficacy waned over time. A deeper understanding of the immune features that contribute to RTS,S/AS01-mediated protection could be beneficial for further vaccine development. In two recent controlled human malaria infection (CHMI) trials of the RTS,S/AS01 vaccine in malaria-naïve adults, MAL068 and MAL071, vaccine efficacy against patent parasitemia ranged from 44% to 87% across studies and arms (each study included a standard RTS,S/AS01 arm with three vaccine doses delivered in four-week-intervals, as well as an alternative arm with a modified version of this regimen). In each trial, RTS,S/AS01 immunogenicity was interrogated using a broad range of immunological assays, assessing cellular and humoral immune parameters as well as gene expression. Here, we used a predictive modeling framework to identify immune biomarkers measured at day-of-challenge that could predict sterile protection against malaria infection. Using cross-validation on MAL068 data (either the standard RTS,S/AS01 arm alone, or across both the standard RTS,S/AS01 arm and the alternative arm), top-performing univariate models identified variables related to Fc effector functions and titer of antibodies that bind to the central repeat region (NANP6) of CSP as the most predictive variables; all NANP6-related variables consistently associated with protection. In cross-study prediction analyses of MAL071 outcomes (the standard RTS,S/AS01 arm), top-performing univariate models again identified variables related to Fc effector functions of NANP6-targeting antibodies as highly predictive. We found little benefit–with this dataset–in terms of improved prediction accuracy in bivariate models vs. univariate models. These findings await validation in children living in malaria-endemic regions, and in vaccinees administered a fourth RTS,S/AS01 dose. Our findings support a “quality as well as quantity” hypothesis for RTS,S/AS01-elicited antibodies against NANP6, implying that malaria vaccine clinical trials should assess both titer and Fc effector functions of anti-NANP6 antibodies.

Compromised SARS-CoV-2-specific placental antibody transfer

SARS-CoV-2 infection causes more severe disease in pregnant women compared to age-matched non-pregnant women. Whether maternal infection causes changes in the transfer of immunity to infants remains unclear. Maternal infections have previously been associated with compromised placental antibody transfer, but the mechanism underlying this compromised transfer is not established. Here, we used systems serology to characterize the Fc profile of influenza-, pertussis-, and SARS-CoV-2-specific antibodies transferred across the placenta. Influenza- and pertussis-specific antibodies were actively transferred. However, SARS-CoV-2-specific antibody transfer was significantly reduced compared to influenza- and pertussis-specific antibodies, and cord titers and functional activity were lower than in maternal plasma. This effect was only observed in third-trimester infection. SARS-CoV-2-specific transfer was linked to altered SARS-CoV-2-antibody glycosylation profiles and was partially rescued by infection-induced increases in IgG and increased FCGR3A placental expression. These results point to unexpected compensatory mechanisms to boost immunity in neonates, providing insights for maternal vaccine design.

Neurovascular Interactions in the Neurologically Compromised Neonatal Brain

Neurological brain injuries such as hypoxic ischaemic encephalopathy (HIE) and associated conditions such as seizures have been associated with poor developmental outcome in neonates. Our limited knowledge of the neurological and cerebrovascular processes underlying seizures limits their diagnosis and timely treatment. Diffuse optical tomography (DOT) provides haemodynamic information in the form of changes in concentration of de/oxygenated haemoglobin, which can improve our understanding of seizures and the relationship between neural and vascular processes. Using simultaneous EEG-DOT, we observed distinct haemodynamic changes which are temporally correlated with electrographic seizures. Here, we present DOT-EEG data from two neonates clinically diagnosed as HIE. Our results highlight the wealth of mutually-informative data that can be obtained using DOT-EEG techniques to understand neurovascular coupling in HIE neonates.

Only one medicine: the future of comparative medicine and clinical research

This article reviews the roots of comparative medicine and argues that during the 20th century it failed to realise its full potential. New opportunities arise from the growing availability of precise, minimally invasive, clinically compatible techniques, which enable us to benefit from the availability of spontaneous analogues of human disease in animals. Particularly with multifactorial diseases, these offer a unique blend of authenticity and acceptability. To realise the full benefits to both animals and humans, we need much closer alignment of human and veterinary clinical medicine.

Ectopic pregnancy and laparoscopy: review of 1197 patients treated by salpingectomy or salpingotomy

The past few decades have witnessed such a rapid rise in the incidence of ectopic pregnancy that it verges on the point of an 'epidemic disease'. Its early detection, with the aid of serum beta-hCG, high resolution ultrasound and the more liberal use of laparoscopy, has dramatically altered the clinical presentation of this disease and permits the use of more conservative methods of management directed towards preserving fertility and reducing morbidity. In this review of 1197 patients, compiled from the English literature, various conservative or tubectomy operative laparoscopic procedures have been employed, with 93% and 98% respectively, being able to avoid further surgery. Among the group treated by the conservative approach, a 6% post-operative complication rate was reported, of which 4% were persistent ectopic, 48% intra-uterine, and 18% repeated ectopic pregnancies. Among the radically treated patients, 2 intra- and 1 post-operative complications necessitated laparotomies. The fertility work-up and performance outcome are less obvious among this group. The benefits, safety and efficacy of each of the laparoscopic options, with appropriate recommendations for their use, are discussed. However, despite the aforementioned dramatic progress, women with previous ectopic pregnancies still have reduced fertility potential. Preventive measures aimed at reducing its overall occurrence therefore seem to be the major factor towards preserving a patient's future fertility potential.