Covalent coupling of HIV-1 glycoprotein trimers to biodegradable calcium phosphate nanoparticles via genetically encoded aldehyde-tags

The usage of antigen-functionalized nanoparticles has become a major focus in the field of experimental HIV-1 vaccine research during the last decade. Various molecular mechanisms to couple native-like trimers of the HIV-1 envelope protein (Env) onto nanoparticle surfaces have been reported, but many come with disadvantages regarding the coupling efficiency and stability. In this study, a short amino acid sequence ("aldehyde-tag") was introduced at the C-terminus of a conformationally stabilized native-like Env. The post-translational conversion of a tag-associated cysteine to formylglycine creates a site-specific aldehyde group without alteration of the Env antigenicity. This aldehyde group was further utilized for bioconjugation of Env trimers. We demonstrated that the low acidic environment necessary for this bioconjugation is not affecting the trimer conformation. Furthermore, we developed a two-step coupling method for pH-sensitive nanoparticles. To this end, we conjugated aldehyde-tagged Env with Propargyl-PEG₃-aminooxy linker (oxime ligation; Step-one) and coupled these conjugates by copper-catalyzed azide-alkyne cycloaddition (Click reaction; Step-two) to calcium phosphate nanoparticles (CaPs) functionalized with terminal azide groups. CaPs displaying orthogonally arranged Env trimers on their surface (o-CaPs) were superior in activation of Env-specific B-cells (in vitro) and induction of Env-specific antibody responses (in vivo) compared to CaPs with Env trimers coupled in a randomly oriented manner. Taken together, we present a reliable method for the site-specific, covalent coupling of HIV-1 Env native-like trimers to the surface of nanoparticle delivery systems. This method can be broadly applied for functionalization of nanoparticle platforms with conformationally stabilized candidate antigens for both vaccination and diagnostic approaches. STATEMENT OF SIGNIFICANCE: During the last decade antigen-functionalized nanoparticles have become a major focus in the field of experimental HIV-1 vaccines. Rational design led to the production of conformationally stabilized HIV-1 envelope protein (Env) trimers - the only target for the humoral immune system. Various molecular mechanisms to couple Env trimers onto nanoparticle surfaces have been reported, but many come with disadvantages regarding the coupling efficiency and stability. In this paper, we describe a highly selective bio-conjugation of Env trimers to the surface of medically relevant calcium phosphate nanoparticles. This method maintains the native-like protein conformation and has a broad potential application in functionalization of nanoparticle platforms with stabilized candidate antigens (including stabilized spike proteins of coronaviruses) for both vaccination and diagnostic approaches.

POS1426 PATIENTS WITH IMMUNE MEDIATED INFLAMMATORY DISEASES ARE OVERREPRESENTED IN LOW- FREQUENCY VIRAL SYMPTOM CLUSTERS

Background:

Viral respiratory infections are common in the general population and result in a spectrum of outcomes ranging from effective viral clearance with no symptoms, to a maladaptive immune response that can result in severe symptomatic disease and death. Although patients with immune-mediated inflammatory diseases (IMID) are considered susceptible to poor outcomes from infectious syndromes, it is not known whether IMID patients are overall more prone to manifest common viral infection symptoms.

Objectives:

To explore frequency patterns of common viral infection symptoms in IMID patients.

Methods:

We previously recruited patients with IMIDs and individuals with no IMIDs for a seroprevalence study between February 1st and April 30th 2020 (1). Participants were questioned for the presence of eleven common viral disease symptoms. We clustered these data using an unsupervised binary data clustering algorithm (2) into 6 symptom clusters based on symptom frequency. Three major clusters (broadly symptomatic, intermediately symptomatic and oligo-/asymptomatic) and 2 sub-clusters (higher and lower frequency) for each major cluster. In addition, qualitative symptom clustering was done. We estimated standardized residuals to quantify the over/underrepresentation of IMID diagnosis frequencies in each subject cluster. We used Poisson regression to compare symptom counts by diagnosis.

Results:

We analyzed 1909 participants (757 with IMIDs; 1152 non-IMID controls; Table 1). Within each major subject cluster (Figure 1A), IMID patients showed the highest positive deviation from the expected frequencies in lower frequency sub-clusters while non IMID controls showed the highest positive deviations in the higher frequency sub-clusters (Figure 1B). Inflammatory bowel disease and psoriasis were remarkably overrepresented in the lower frequency sub-cluster of the broadly-symptomatic cluster while RA was overrepresented in the lower frequency sub-clusters of intermediate and oligo-/asymptomatic clusters. X axis of Figure 1A presents qualitative symptom clusters. Regression analysis shows that RA patients among other IMIDs reported overall less symptoms (RR= 0.69, 95%CI, 0.58 - 0.80) compared to non-IMID controls.

Figure 1.

A) distribution of common viral respiratory disease symptoms across patient and symptom clusters. B) Standardized residuals indicating deviation from expected frequencies of IMID diagnoses across patient clusters. sob: shortness of breath, mskpain: musculoskeletal pain

Conclusion:

This analysis shows that symptoms of common respiratory viral infections are less frequent in RA patients and to a lesser extent in other IMID patient. As major clusters in this analysis can also be considered to represent exposure categories, these data suggest that IMIDs or their treatments may mitigate common respiratory viral infection symptoms.

References:

[1]Simon D. et al. Nat Commun (2020) 11, 3774

[2]Bhatia P. et al. J. Stat. Softw (2017) 76(9)

Table 1.

Participant characteristics and distribution of IMID diagnoses across subject clusters.

ClustersBroad SymptomaticIntermediate SymptomaticOligo-AsymptomaticOverallHigherLowerHigherLowerHigherLowerN190910185412259283769Age, years, mean (SD)45.4(15.2)42.4(13.3)47.3 (15.2)42.4(12.9)50.4(15.5)41.8(14.9)46.8(15.9)Male1080 (56.6)42 (41.6)38 (44.7)196 (47.6)137 (52.9)178 (62.9)489 (63.6)Diagnosis, n(%)No-IMID1152 (60.3)72 (71.3)44 (51.8)280 (68.0)112 (43.2)207 (73.1)437 (56.8)RA226 (11.8)7 (6.9)5 (5.9)29 (7.0)56 (21.6)17 (6.0)112 (14.6)IBD178 (9.3)5 (5.0)15 (17.6)46 (11.2)29 (11.2)19 (6.7)64 (8.3)SpA142 (7.4)7 (6.9)5 (5.9)23 (5.6)25 (9.7)14 (4.9)68 (8.8)Psoriasis89 (4.7)4 (4.0)9 (10.6)14 (3.4)8 (3.1)13 (4.6)41 (5.3)Other122 (6.4)6 (5.9)7 (8.2)20 (4.9)29 (11.2)13 (4.6)47 (6.1)Symptom count/patient, mean (SD)1.2 (1.7)6.0 (1.3)3.9 (1.1)2.2 (1.0)1.5 (0.6)0.5 (0.5)0.0 (0.0)

IBD, inflammatory bowel disease.

Acknowledgements:

This study was supported by the Deutsche Forschungsgemeinschaft (DFG- FOR2886 PANDORA and the CRC1181), the Bundesministerium für Bildung und Forschung (BMBF; project MASCARA), the H2020 GA 810316 - 4D-Nanoscope ERC Synergy Project, the IMI funded project RTCure, the Emerging Fields Initiative MIRACLE of the Friedrich-Alexander-Universität Erlangen-Nürnberg as well as the Schreiber Stiftung gemeinnützige Gesellschaft mbH.

Disclosure of Interests:

None declared

A User-oriented Protocol for Integrating Heterogeneous Communication Systems of Medical Facilities Using Ports

The crucial feature of future communication systems in hospitals will be the heterogeneity between the individual systems. People working in a hospital do not communicate via data objects, but via highly complex functions like preparation of a patient report or diagnosis of patients’ symptoms and signs. Essentially such tasks are accomplished by initiating remote functions in various modes of a communication system. The aim of the MEDAS protocol developed by our group is to propose a definition of such a high-level medical protocol and then to implement it. Our user-oriented protocol permits information exchange between heterogeneous systems. Modules and functions are defined. Message passing to and from a processor is realized using ports. The protocol sequence of every communication request is described. The relation of ports to the ISO model is specified. First experiences in a network for a medical school are reported.

Estimating Relative Risk from Heterogeneous Strata

The uncritical use of risk estimators can lead to serious bias. The estimation of overall risk ratios for heterogeneous strata and the weights used have been discussed recently. This paper starts with the definition of relative risk in the population, considering heterogeneous strata and a cofactor, using weight functions. From this general formula four different weight functions leading to four different overall measures of relative risk (RR1, RR1, RR3, RR4 ) are. derived as special cases. The estimability of the parameters in relation to the underlying sampling design is investigated. Consistent estimators are provided and the asymptotic distributions of the estimators are given for prospective cohort studies, case control studies with fixed strata and case control studies with given sample sizes. For some of the estimates the . asymptotic variances are given. It is shown that for case control studies with fixed strata neither the Mantel-Haenszel estimator nor another estimator of this class is consistent. An extension to more than two risk levels is provided and the relationships between various risk measures and other implications are commented on. A way is described to improve risk estimation by using information from the population. An example for cohort studies is given. Generally we propose to use RR3 , which lies between RR1 and RR2 and can be estimated more precisely using the sometimes available distribution of the cofactor in the population. If the relative risk across strata is heterogeneous, logistic models for the construction of a single risk indicator have some drawbacks.

Long-Term Studies — A Challenge to Medical Informatics

The paper describes the aims of long-term studies and the problems involved for medical informatics and shows ways to their solution.

Umfrage zum Entwicklungsstand der EDVin den Krankenhäusern der BRD

Es wird über eine zweistufige Umfrageaktion, bei 800 Krankenhäusern der BRD mit über 250 Betten (ohne Universitätskliniken) zum Einsatz der EDV berichtet. Die erste Stufe brachte mit 686 Antworten (85,?°/o) eine hohe Rücklaufquote und ergab, daß ca. 35% EDV bereits einsetzen, ca. 19%> den Einsatz in den nächsten zwei Jahren und ca. 37% den Einsatz später planen. In der zweiten Umfragestufe wurde zwischen bereits einsetzenden und planenden Krankenhäusern unterschieden. Von insgesamt 323 verschickten Fragebogen kamen 165 zurück (51,1%). Gründe für die Einführung, Einsatzgebiete, benutzte Informationsquellen, die Unterstützung, die aufgestellten oder mitbenutzten Anlagen und die in Anspruch genommenen Rechenzentren werden tabellarisch wiedergegeben. In der Diskussion wird die Diskrepanz zwischen hohem Interesse und tatsächlich aufgestellten Anlagen herausgestellt, die Ausdehnung der Einsatzgebiete von der Verwaltung auf medizinische Bereiche sowie den Organisationsund Wirtschaftsbereich und die notwendige Verbesserung der derzeitigen Informationsquellen der Krankenhäuser hervorgehoben.

Untersuchung zur Genauigkeit einer automatischen EKG-Vermessung

Zur Überprüfung der Genauigkeit einer automatischen EKG-Vermessung wurde gesunden Versuchspersonen das EKG nach. Einthoven, Goldberger und Wilson abgenommen und durch ein Computer-Programm vermessen. In einer dreifachen Varianzanalyse wurde der Einfluß, der durch die maschinelle Vermessung entsteht, mit anderen Fehlereinflüssen verglichen. Neben Aussagen darüber, welche Meßgroße in welcher EKG-Ableitung am zuverlässigsten ermittelt werden kann, wurden zwei FehlerKoeffizienten definiert, von denen der eine (FKJ nur den Vermessungsfehler selbst und der andere (FKj) die gesamte biologische und sonstige Variation zwischen Tagen und Tageszeiten sowie zwischen den Abnahmebedingungen (Elektrodenlage) enthält. FKt ist nur für wenige Meßgrößen 5% oder besser, FKj liegt häufig in der Größenordnung von 50%. An Hand dieser Ergebnisse wird die Problematik eines einzelnen EKG-Meßwerts und der automatischen EKG-Vermessung diskutiert. Es wird empfohlen, derartige Untersuchungen zur Qualitätskontrolle beim Routineeinsatz mitzuführen.

Design Elements for a Computerized Patient Record

Computerized medical record systems have to present user-and problem-oriented views of a patient record to health-care professionals. Presentation and manipulation of data must be easily adaptable to current and future demands of medical specialties and specific settings. During the definition, development and evaluation of a prototype of a computerized patient record system, design elements were elaborated to support physicians and other health-care professionals. Our approach shows a high degree of flexibility and adaptability to specific needs, problem orientation and connectivity to other systems, via a hospital information network. The explicit description of the contents of a patient record allows to augment the number of items that can be recorded without modifying the data structure. New views on patient data can be added to the system without interfering with the routine use of the system. Application in several medical specialties proved the feasibility of our prototype.

Information Processing in Healthcare at the Start of the third Millennium: Potential and Limitations

The 21st century is said to be a century of the information society. We should be aware that continuing progress in information processing methodology (IPM) and information and communication technology (ICT) is changing our societies, including medicine and health care. At the start of the third Millennium we should ask ourselves, what progress can we expect from modern IPM/ICT for healthcare in the coming decade, what concerns does the information society have to face, and what steps have to be taken. These questions were addressed by clinicians, researchers and industrial representatives in a panel discussion at the joint conference ISCB-GMDS-99 of the International Society of Clinical Biostatistics and the German Society for Medical Informatics, Biometry and Epidemiology. Important aspects raised by the panelists and in the subsequent discussion were: (1) the main goal of expanding IPM/ICT should be to further improve quality of care, while maintaining reasonable costs; (2) with the support of modern IPM and ICT the boundaries between inpatient and outpatient care will fade away enabling a more efficient, patient-centered health care; (3) cooperation between health-care professionals will increase; there will be different ways of communication between them and with the patient, including modern ICT and the Internet; (4) society must be concerned with achieving equal opportunities in being informed about and in using new ICT; (5) misuse of data will remain a serious problem and can become an obstacle to progress.

Risk Analysis in Cohort Studies with Heterogeneous Strata. A Global χ2-Test for Dose-Response Relationship, Generalizing the Mantel-Haenszel Procedure

In cohort studies the Mantel-Haenszel estimator OR̂ MH is computed from sample data and is used as a point estimator of relative risk. Test-based confidence intervals are estimated with the help of the asymptotic chi-squared distributed MH-statistic χ2 MHS . The Mantel-exten-sion-chi-squared is used as a test statistic for a dose-response relationship. Both test statistics – the Mantel-Haenszel-chi as well as the Mantel-extension-chi – assume homogeneity of risk across strata, which is rarely present. Also an extended nonparametric statistic, proposed by Terpstra, which is based on the Mann-Whitney-statistics assumes homogeneity of risk across strata.

We have earlier defined four risk measures RR k j (k = 1,2,...,4) in the population and considered their estimates and the corresponding asymptotic distributions. In order to overcome the homogeneity assumption we use the δ-method to get “test-based” confidence intervals. Because the four risk measures RR k j are presented as functions of four weights gik we give, consequently, the asymptotic variances of these risk estimators also as functions of the weights g ik in a closed form. Approximations to these variances are given.

For testing a dose-response relationship we propose a new class of χ2(1)-distributed global measures Ĝk and the corresponding global χ2-test. In contrast to the Mantel-extension-chi homogeneity of risk across strata must not be assumed. These global test statistics are of the Wald type for composite hypotheses. The Mantel-extension-chi is a special case of the global-chi statistic and it is further shown that the Mantel-extension-chi can be expressed as a special weighted Terpstra statistic. Formulas for computing estimators of the global measures are provided. Three elaborated examples with hypothetical data of varying structure show, that the Mantel-extension-chi is systematically biased, generally overestimates the dose-response relation and leads to wrong conclusions, when heterogeneity is present. This is consistent with our theoretical considerations. In case of heterogeneity, when one wants to test an association between exposure and effect, or a dose-response relationship, the new global-χ2-test should be used in cohort studies.

Mucosal expression of DEC-205 targeted allergen alleviates an asthmatic phenotype in mice

Considering the rising incidence of allergic asthma, the symptomatic treatments that are currently applied in most cases are less than ideal. Specific immunotherapy is currently the only treatment that is able to change the course of the disease, but suffers from a long treatment duration. A gene based immunization that elicits the targeting of allergens towards dendritic cells in a steady-state environment might have the potential to amend these difficulties. Here we used a replication deficient adenovirus to induce the mucosal expression of OVA coupled to a single-chain antibody against DEC-205. A single intranasal vaccination was sufficient to mitigate an OVA-dependent asthmatic phenotype in a murine model. Invasive airway measurements demonstrated improved lung function after Ad-Dec-OVA treatment, which was in line with a marked reduction of goblet cell hyperplasia and lung eosinophilia. Furthermore OVA-specific IgE titers and production of type 2 cytokines were significantly reduced. Together, the here presented data demonstrate the feasibility of mucosal expression of DEC-targeted allergens as a treatment of allergic asthma.