Recall Responses to Tetanus and Diphtheria Vaccination Are Frequently Insufficient in Elderly Persons

Demographic changes and a more active life-style in older age have contributed to an increasing public awareness of the need for lifelong vaccination. Currently many older persons have been vaccinated against selected pathogens during childhood but lack regular booster immunizations. The impact of regular vaccinations when started late in life was analyzed in an open, explorative trial by evaluating the immune response against tetanus and diphtheria in healthy older individuals. 252 persons aged above 60 years received a booster vaccination against tetanus, diphtheria, pertussis and polio and a subcohort (n=87) was recruited to receive a second booster vaccination against tetanus, diphtheria and pertussis 5 years later. The percentage of unprotected individuals at the time of enrollment differed substantially for tetanus (12%) and diphtheria (65%). Despite protective antibody concentrations 4 weeks after the first vaccination in almost all vaccinees, antibodies had again dropped below protective levels in 10% (tetanus) and 45% (diphtheria) of the cohort after 5 years. Protection was restored in almost all vaccinees after the second vaccination. No correlation between tetanus- and diphtheria-specific responses was observed, and antibody concentrations were not associated with age-related changes in the T cell repertoire, inflammatory parameters, or CMV-seropositivity suggesting that there was no general biological “non-responder type.” Post-vaccination antibody concentrations depended on pre-existing plasma cells and B cell memory as indicated by a strong positive relationship between post-vaccination antibodies and pre-vaccination antibodies as well as antibody-secreting cells. In contrast, antigen-specific T cell responses were not or only weakly associated with antibody concentrations. In conclusion, our findings demonstrate that single shot vaccinations against tetanus and/or diphtheria do not lead to long-lasting immunity in many elderly persons despite administration at relatively short intervals. Sufficient antigen-specific B cell memory B generated by adequate priming and consecutive booster vaccinations and/or exposure is a prerequisite for long-term protection. Trial Registration EU Clinical Trials Register (EU-CTR); EudraCT number 2009-011742-26; www.clinicaltrialsregister.eu/ctr-search/trial/2009-011742-26/A

Analyse Epstein-Barr Virus (EBV)-spezifischer virologischer und immunologischer Parameter bei EBV-assoziierten Erkrankungen und Patienten unter Immunsuppression

Mehr als 95% der erwachsenen Bevölkerung sind mit dem Epstein-Barr Virus infiziert. Nach der Primärinfektion persistiert das Virus lebenslang in ruhenden B-Zellen. Bei gesunden Trägern kommt es immer wieder zur Freisetzung des Virus im Oropharynx. Eine effektive immunologische Kontrolle verhindert jedoch eine unkontrollierte Replikation des Virus und die Proliferation latent infizierter B-Zellen. Unter Immunsuppression (z.B. nach Transplantationen) kann dieses immunologische Gleichgewicht gestört sein. Es kommt zu viralen Reaktivierungen und in einigen Prozent der Patienten zu EBV-assoziierten Lymphoproliferationen (PTLD; post-transplant lymphoproliferative disease). In dieser Arbeit wurden sensitive real-time PCR-Systeme zur Quantifizierung viraler mRNAs etabliert um virale Expressionsmuster in vitro und in vivo detailliert zu analysieren. Dazu wurden Transkripte, die zu verschiedenen Zeitpunkten während des lytischen Zyklus exprimiert werden (BZLF1 [immediate early], BALF5 [early], BLLF1 [late]) und latente Transkripte, die die unterschiedlichen in der Literatur beschriebenen Latenzformen repräsentieren (EBNA1, EBNA2, LMP1), ausgewählt. Da nicht alle dieser Transkripte gespleißt sind, wurde eine Methode, mit der zuverlässig DNA-freie RNA präpariert werden kann, etabliert, so daß keine sequenzbasierte Unterscheidung von RNA und DNA notwendig war. Um die Methode auch im Rahmen von Routine-Untersuchung einsetzbar zu machen wurde die Zuverlässigkeit und Reproduzierbarkeit aller Arbeitsschritte eingehend geprüft. In verschieden EBV-positiven Zelllinien konnte gezeigt werden, daß die latenten Gene stärker exprimiert werden als die lytischen Gene, was mit der Annahme, daß nur einige Prozent der Zellen in vitro spontan in den lytischen Zyklus eintreten, übereinstimmt. Im Hauptteil der Arbeit wurde in Kombination mit serologischen Untersuchungen und der Detektion viraler DNA in Serum und isolierten Lymphozyten die virale Aktivität in gesunden Trägern und in Patienten mit EBV-assoziierten Erkrankungen detailliert untersucht. Sowohl bei gesunden Trägern als auch bei Patienten unter Immunsuppression wurden alle untersuchten latenten Transkripte - wenn auch in unterschiedlichem Ausmaß - exprimiert. Im Gegensatz zu der Annahme, daß in ruhenden B-Zellen gesunder Träger nur EBNA1 und eventuell LMP2A exprimiert werden, konnten in einem Teil der Probanden auch EBNA2- und LMP1-Transkripte nachgewiesen werden. In ca. 10% der Proben fand sich außerdem BLLF1-mRNA, was für einen Übergang des Virus in den lytischen Zyklus in diesen Zellen spricht. Die postulierten Latenzformen und Expressionsmuster scheinen also nicht allgemeingültig zu sein. Im Rahmen einer prospektiven Studie (47 Patienten nach Nieren- bzw. Stammzelltransplantation, Beobachtungszeitraum 12 Monate) konnte bei Immunsupprimierten häufiger als in gesunden Trägern virale DNA in Lymphozyten nachgewiesen werden. Die Expression lytischer Gene war jedoch in beiden Kollektiven vergleichbar. Unterschiede zeigten sich in der Expression der latenten Gene, die unter Immunsuppression stärker exprimiert waren. Dies läßt den Schluß zu, daß die erhöhte Viruslast bei Patienten unter Immunsuppression nicht auf eine lytische Replikation des Virus, sondern vielmehr auf eine Expansion latent infizierter B-Zellen zurückzuführen ist. Keiner der 47 Patienten entwickelte während des Beobachtungszeitraumes eine EBV-assoziierte Lymphoproliferation; leicht erhöhte virale Aktivität reicht also als prognostischer Marker für eine PTLD nicht aus. Sowohl bei Patienten unter Immunsuppression als auch bei gesunden Trägern schwankten die Titer EBV-spezifischer Antikörper stark im zeitlichen Verlauf. Ein Zusammenhang zwischen Antikörper-Titern und EBV-assoziierten Komplikationen nach Transplantation �wie er in der Literatur diskutiert wird- konnte nicht gezeigt werden. Bei ausgewählten Patienten wurde außerdem die EBV-spezifische T-Zell-Antwort untersucht. Die Zahl spezifischer T-Zellen schwankte auch bei gesunden Trägern im zeitlichen Verlauf stark. Aus diesem Grund ist eine einmalige Untersuchung der T-Zell-Antwort nicht aussagekräftig. Die Untersuchungen an immunsupprimierten Patienten wurden deshalb über einen Zeitraum von einigen Monaten durchgeführt. Bei allen untersuchten Patienten konnten einige Wochen bzw. Monate nach Transplantation EBV-spezifische T-Zellen nachgewiesen werden. Die Zahl der spezifischen cytotoxischen T-Zellen unterschied sich dabei nicht von der in gesunden Trägern. Man kann also davon ausgehen, daß auch unter der heute üblichen Immunsuppression EBV in den meisten Fällen immunologisch kontrolliert werden kann

Different Types of Isomorphisms of Drawings of Complete Multipartite Graphs

Simple drawings are drawings of graphs in which any two edges intersect at most once (either at a common endpoint or a proper crossing), and no edge intersects itself. We analyze several characteristics of simple drawings of complete multipartite graphs: which pairs of edges cross, in which order they cross, and the cyclic order around vertices and crossings, respectively. We consider all possible combinations of how two drawings can share some characteristics and determine which other characteristics they imply and which they do not imply. Our main results are that for simple drawings of complete multipartite graphs, the orders in which edges cross determine all other considered characteristics. Further, if all partition classes have at least three vertices, then the pairs of edges that cross determine the rotation system and the rotation around the crossings determine the extended rotation system. We also show that most other implications -- including the ones that hold for complete graphs -- do not hold for complete multipartite graphs. Using this analysis, we establish which types of isomorphisms are meaningful for simple drawings of complete multipartite graphs.Comment: Appears in the Proceedings of the 31st International Symposium on Graph Drawing and Network Visualization (GD 2023

The immunoregulatory effects of CMV-infection in human fibroblasts and the impact on cellular senescence

<p>Abstract</p> <p>Background</p> <p>As a chronic antigenic stressor human Cytomegalovirus (CMV) contributes substantially to age-related alterations of the immune system. Even though monocytes have the greatest propensity for CMV-infection and seem to be an important host for the virus during latency, fibroblasts are also discussed to be target cells of CMV <it>in vivo</it>. However, little is known so far about general immunoregulatory properties of CMV in fibroblasts. We therefore investigated the immunoregulatory effects of CMV-infection in human lung fibroblasts and the impact on replicative senescence.</p> <p>Findings</p> <p>We observed that CMV-infection led to the induction of several immunoregulatory host cell genes associated with the innate and adaptive immune system. These were genes of different function such as genes regulating apoptosis, cytokines/chemokines and genes that are responsible for the detection of pathogens. Some of the genes upregulated following CMV-infection are also upregulated during cellular senescence, indicating that CMV causes an immunological phenotype in fibroblasts, which is partially reminiscent of replicative senescent cells.</p> <p>Conclusion</p> <p>In summary our results demonstrate that CMV not only affects the T cell pool but also induces inflammatory processes in human fibroblasts.</p

Long-term maintenance of diphtheria-specific antibodies after booster vaccination is hampered by latent infection with Cytomegalovirus

Abstract: Many currently used vaccines are less immunogenic in the elderly compared to young adults. The impact of latent infection with Cytomegalovirus (CMV) on vaccine-induced antibody responses has been discussed controversially. We have demonstrated that recall responses to diphtheria vaccination are frequently insufficient in elderly persons and that antibody concentrations decline substantially within 5 years. In the current study we show that within a cohort of healthy elderly (n = 87; median age 71 years, range 66–92) antibody responses to a booster vaccination against diphtheria do not differ between CMV-negative and CMV-positive individuals 4 weeks after vaccination.. However, the goal of diphtheria-vaccination is long-term protection and this is achieved by circulating anti-toxin antibodies. Diphtheria-specific antibody concentrations decline faster in CMV-positive compared to CMV-negative older adults leading to an increased proportion of persons without protective antibody concentrations 5 years after booster vaccination and endangering long-term protection. This finding could be relevant for vaccination schedules

Shooting Stars in Simple Drawings of Km,nK_{m,n}

Simple drawings are drawings of graphs in which two edges have at most one common point (either a common endpoint, or a proper crossing). It has been an open question whether every simple drawing of a complete bipartite graph $K_{m,n}$ contains a plane spanning tree as a subdrawing. We answer this question to the positive by showing that for every simple drawing of $K_{m,n}$ and for every vertex $v$ in that drawing, the drawing contains a shooting star rooted at $v$, that is, a plane spanning tree containing all edges incident to $v$.Comment: Appears in the Proceedings of the 30th International Symposium on Graph Drawing and Network Visualization (GD 2022

Concentric and eccentric endurance exercise reverse hallmarks of T-Cell senescence in pre-diabetic subjects

The peripheral T-cell pool undergoes a striking age associated remodeling which is accelerated by progressive insulin resistance. Exercise training is known to delay several aspects of T-cell senescence. The purpose of the current study was to investigate the effect of 3 weeks regular concentric or eccentric endurance exercise training on the composition of the T-cell compartment in pre-diabetic subjects. Sixteen male older adults with impaired glucose tolerance were recruited and performed either concentric exercise (CE) or eccentric exercise (EE) walking 3 times a week for 3 weeks. Fasting venous blood sampling was performed before training and after the training intervention. Various T-cell subpopulations were analyzed by flow cytometry. We did not find significant time × group effects (interaction) but found several significant time effects for cell type ratios and cell subsets proportions. There was an increase of the CD4+/CD8+ (0.55 ± 0.85%; p = 0.033) and CD4+/CD3+ ratio (5.63 ± 8.44%; p = 0.018) and a decrease of the CD8+/CD3+ ratio (-0.95 ± 1.64%; p = 0.049) after training. We found proportional increases of CD4+/CCR7+/CD45RO+ central memory cells (5.02 ± 7.68%; p = 0.030), naïve CD8+/CCR7+/CD45RO- (3.00 ± 6.68%; p = 0.047) and CD8+/CCR7+/CD45RO+ central memory cells (3.01 ± 3.70%; p = 0.009), while proportions of CD4+/CCR7-/CD45RO- TEMRA cells (-2.17 ± 4.66%; p = 0.012), CD8+/CCR7-/CD45RO- TEMRA cells (-5.11 ± 7.02%; p = 0.018) and CD16+ cells (-4.67 ± 6.45%; p = 0.016) decreased after training. 3 weeks of either CE or EE were effective in reversing hallmarks of T-cell senescence in pre-diabetic subjects. It is suggested that exercise stimulates production and mobilization of naïve T-cells, while differentiated TEMRA cells might disappear by apoptosis

Drawings of Complete Multipartite Graphs up to Triangle Flips

For a drawing of a labeled graph, the rotation of a vertex or crossing is the cyclic order of its incident edges, represented by the labels of their other endpoints. The extended rotation system (ERS) of the drawing is the collection of the rotations of all vertices and crossings. A drawing is simple if each pair of edges has at most one common point. Gioan's Theorem states that for any two simple drawings of the complete graph Kn with the same crossing edge pairs, one drawing can be transformed into the other by a sequence of triangle flips (a.k.a. Reidemeister moves of Type 3). This operation refers to the act of moving one edge of a triangular cell formed by three pairwise crossing edges over the opposite crossing of the cell, via a local transformation. We investigate to what extent Gioan-type theorems can be obtained for wider classes of graphs. A necessary (but in general not sufficient) condition for two drawings of a graph to be transformable into each other by a sequence of triangle flips is that they have the same ERS. As our main result, we show that for the large class of complete multipartite graphs, this necessary condition is in fact also sufficient. We present two different proofs of this result, one of which is shorter, while the other one yields a polynomial time algorithm for which the number of needed triangle flips for graphs on n vertices is bounded by O(n16). The latter proof uses a Carathéodory-type theorem for simple drawings of complete multipartite graphs, which we believe to be of independent interest. Moreover, we show that our Gioan-type theorem for complete multipartite graphs is essentially tight in the following sense: For the complete bipartite graph Km, n minus two edges and Km, n plus one edge for any m, n ≥ 4, as well as Kn minus a 4-cycle for any n ≥ 5, there exist two simple drawings with the same ERS that cannot be transformed into each other using triangle flips. So having the same ERS does not remain sufficient when removing or adding very few edges

Urea-Mediated Cross-Presentation of Soluble Epstein-Barr Virus BZLF1 Protein

Soluble extracellular proteins usually do not enter the endogenous human leukocyte antigen (HLA) I–dependent presentation pathway of antigen-presenting cells, strictly impeding their applicability for the re-stimulation of protein-specific CD8+ cytotoxic T lymphocytes (CTL). Here we present for the Epstein-Barr virus (EBV) BZLF1 a novel strategy that facilitates protein translocation into antigen-presenting cells by its solubilisation in high molar urea and subsequent pulsing of cells in presence of low molar urea. Stimulation of PBMC from HLA-matched EBV-seropositive individuals with urea-treated BZLF1 but not untreated BZLF1 induces an efficient reactivation of BZLF1-specific CTL. Urea-treated BZLF1 (uBZLF1) enters antigen-presenting cells in a temperature-dependent manner by clathrin-mediated endocytosis and is processed by the proteasome into peptides that are bound to nascent HLA I molecules. Dendritic cells and monocytes but also B cells can cross-present uBZLF1 in vitro. The strategy described here has potential for use in the development of improved technologies for the monitoring of protein-specific CTL