Animal Coronaviruses Induced Apoptosis

Apoptosis is a form of programmed death that has also been observed in cells infected by several viruses. It is considered one of the most critical innate immune mechanisms that limits pathogen proliferation and propagation before the initiation of the adaptive immune response. Recent studies investigating the cellular responses to SARS-CoV and SARS-CoV-2 infection have revealed that coronaviruses can alter cellular homeostasis and promote cell death, providing evidence that the modulation of apoptotic pathways is important for viral replication and propagation. Despite the genetic diversity among different coronavirus clades and the infection of different cell types and several hosts, research studies in animal coronaviruses indicate that apoptosis in host cells is induced by common molecular mechanisms and apoptotic pathways. We summarize and critically review current knowledge on the molecular aspects of cell-death regulation during animal coronaviruses infection and the viral–host interactions to this process. Future research is expected to lead to a better understanding of the regulation of cell death during coronavirus infection. Moreover, investigating the role of viral proteins in this process will help us to identify novel antiviral targets related to apoptotic signaling pathways

Comparison of the Level of Awareness about the Transmission of Echinococcosis and Toxocariasis between Pet Owners and Non-Pet Owners in Greece

Ζoonotic parasitic diseases that can occur through animal contact pose risks to pets, their owners and to their bond. This study aims to assess the level of knowledge about zoonoses, specifically echinococcosis and toxocariasis, among cat/dog owners and non-pet owners in Greece. Multiple-choice questionnaires were designed to obtain data regarding the knowledge of pet and non-pet owners on echinococcosis and toxocariasis, including signs and symptoms of these zoonoses, ways of transmission and precautions that need to be taken into account in order to avoid it. A total of 185 questionnaires were retrieved and data was expressed as absolute (Ν) and relative frequencies (%). Associations between pet ownership, residence and outcome variables were evaluated using the Fisher exact test and Chi-squared test, respectively. Multifactorial linear regression analysis was used to investigate the cross-sectional association between demographic characteristics and the awareness of helminthic zoonoses. All tests were two-sided and statistical significance was set at p < 0.05. Our study revealed a disturbing lack of awareness of echinococcosis and toxocariasis (mean zoonotic knowledge score 8.11 ± 3.18) independently of pet ownership. Surprisingly, in some cases the ignorance of pet owners exceeded that of non-pet owners. Given the progressive impact of toxocariasis in public health and the high prevalence of echinococcosis in the Mediterranean region, measures should be taken to inform people about zoonoses and eliminate their putative transmission

Investigation of leishmania donovani membrane antigens with pathophysiological significance

The protozoan parasites of the genus Leishmania are the causative agents of leishmaniasis, a worldwide spread disease. The parasites are transmitted to humans, carnivores, rodents etc. by a female phlebotominae sand fly vector, which becomes infected during the blood meal. The flagellated motile promastigote form penetrates the skin of the hosts by the bites of infected sandfly vectors. In the mammalian host the promastigotes are phagocytosed by cells of mononuclear system, where they convert to a nonmotile amastigote form. The knowledge of the chemical, enzymatic and antigenic composition of the surface membrane is important in defining the mechanisms by which Leishmania survives and multiplies into macrophages. The aim of the present study was to identify and characterize L.infantum membrane antigens of a potentional pathophysiological significance, by production of monoclonal antibodies (mAbs) against isolated L.infantum membrane antigens.Thirty mAbs were produced at the Laboratory of Biochemistry, Hellenic Pasteur Institute. Fusions were carried out by the direct cloning method. One of them mAb X2I9 (binds to intact parasites, cross reacts with other species of the genus Leishmania, belongs to IgG1 subclass), was selected for further studies. A 78-kDa glycoprotein associated with the membrane of L.infantum promastigotes was immunopurified by mAb X2I9. This mAb was subsequently found that binds to human 78kDa transferrin as well. Binding of X2I9 to human transferrin was completely abolished when the mAb was preabsorbed by Leishmania membranes. These results indicate that the 78k-Da Leishmania membrane associated glycoprotein and transferrin have common antigenic epitope(s). The 78k-Da Leishmania membrane associated glycoprotein was released in soluble non aggregated form by mild treatment of membranes with acetic acid and saline for effective removing surface bound transferrin. Anti-transferrin polyclonal antibodies recognize both the membrane –associated and the soluble form of the 78k-Da glycoprotein (share common antigenic epitopes). The later characterized further as an iron containing protein. The collected data indicate that the 78-kDa Leishmania membrane associated glycoprotein is transferrin.Data binding results of the 125I-human transferrin to Leishmania – purified preparations indicate the presence of a high affinity saturable binding site (Kd=2.2X10-8M) specific for transferrin, comparable to the Kd measured for transferrin receptors on mammalian cell types, suggesting the functional similarity to these receptors.The Leishmania transferrin receptor was first identified by SDS-PAGE followed by Western blot analysis, using 125I- transferrin as a 70-kDa protein. It has been isolated initially from L.infantum promastigotes by affinity chromatography on a transferrin–Sepharose column and then from Leishmania major promastigotes. This receptor (characterized as an integral membrane glycoprotein) has the same mobility when analyzed under reducing and nonreducing conditions of SDS-PAGE, indicating that it lacks intermolecular disulfide. The oligomeric state of the 70-kDa receptor was further investigated by gel filtration. It appears to be a monomer in a solution binding transferrin in the ratio 1:1.The immunological differences between Leishmania and mammalian transferrin receptor was investigated by the use of a) mAbs that recognize human (B3/25 and OKT9) and murine (R17 208) receptors and b) by polyclonal antibodies to Leishmania (anti-70kDa) and murine (anti-90kDa) transferrin receptors. it was found that the two receptors are antigenically distinct. Preliminary, Northern blot analysis of Leishmania promastigotes RNA with the complementary DNA clone TRF-2 of mouse transferrin receptor showed that the parasite gene coding for Leishmania receptor, under stringent conditions of hybridization, does not appear to have any homology with the mouse gene.The identification of transferrin receptor in the Leishmania membrane characterizing the mammalian cells, isolation of the Leishmania transferrin receptor the biochemical and immunological characterization of the molecule as well as the investigation of its functional and structural similarity to the corresponding receptor in mammalian cells was first performed internationally in this doctoral thesis.H λεϊσμανίωση αποτελεί την δεύτερη σε αριθμό κρουσμάτων ασθένεια πρωτοζωικής προέλευσης μετά την ελονοσία και έχει καταταχθεί από την Παγκόσμια Οργάνωση Υγείας μεταξύ των έξι σημαντικότερων τροπικών νοσημάτων. Αιτιολογικός παράγοντας του νοσήματος είναι τα είδη των ενδοκυτταρικών πρωτόζωων παρασίτων του γένους Leishmania. Η γνώση των βιοχημικών και αντιγονικών ιδιοτήτων της μεμβράνης της προμαστιγωτής μορφής του παρασίτου Leishmania είναι σημαντική στην μελέτη του τρόπου επιβίωσης του παρασίτου μέσα στα μακροφάγα. Σκοπός της διατριβής αποτελεί η αναζήτηση και ο χαρακτηρισμός των αντιγόνων μεμβράνης του παρασίτου προκειμένου να διαπιστωθεί η συμμετοχή τους στις σχέσεις παρασίτου-ξενιστή, η σημασία τους στην επιβίωση του παρασίτου και η πιθανή χρησιμοποίηση τους στη διάγνωση, στη θεραπεία και την πρόληψη της λεισμανίωσης.Για τον σκοπό αυτό παρασκευάσθηκαν, με τη μέθοδο «κατευθείαν κλωνοποίησης», 30 είδη μονοκλωνικών αντισωμάτων σε ποντίκια BALB/c τα οποία ανοσοποιήθηκαν με κλάσματα της μεμβράνης του παρασίτου L.infantum (μέθοδος χρωματογραφίας ηθμού σε συνθήκες υψηλής πίεσης). Για εκτενέστερη μελέτη επιλέχθηκαν τα μονοκλωνικά αντισώματα Χ2Ι9 (ραδιοανοσολογική δοκιμασία, στερεής φάσης), τα οποία συνδέονται με επίτοπους της επιφάνειας των παρασίτων (έμμεσος ανοφοφθορισμός, ανίχνευση πρωτεϊνών με την μέθοδο ανοσοαποτύπωση σε φύλλα νιτροκυτταρίνης), παρουσιάζουν διασταυρωτή αντίδραση με άλλα είδη λεϊσμανιών και ανήκουν στην τάξη IgG1 (ανοσοενζυμική δοκιμασία, μέθοδος LAB). Mε τη χρησιμοποίηση στήλης ανοσοσυγγένειας, στην οποία συνδέθηκαν τα μονοκλωνικά αντισώματα Χ2Ι9 απομονώθηκε από τη μεμβράνη του παρασίτου μία γλυκοπρωτεΐνη μοριακού βάρους 78-kDa (πήκτωμα πολυακρυλαμιδίου 7-17%, SDS-PAGE ανάλυση) που ταυτίζεται με την τρανσφερρίνη του ανθρώπου (σιδηροπρωτεΐνη, κοινοί αντιγονικοί επίτοκοι). Ο έλεγχος της ανταγωνιστικής πρόσδεσης και ανάλυση κατά Scatchard της τρανφερρίνης σε αμαστιγωτές μορφές (ελήφθησαν από δερματικές αλλοιώσεις ποντικών μολυσμένων με L.mexicana amanzoniensis) και σε προμαστιγωτές μορφές του παρασίτου (L.infantum) ανέδειξε την ύπαρξη ειδικών θέσεων σύνδεσης της τρανσφερρίνης στη μεμβράνη του παρασίτου, υψηλής συγγένειας (Kd=2.2X10-8 M ) ανάλογης με την υψηλή συγγένεια του αντίστοιχου υποδοχέα τρανφερρίνης του ανθρώπου. Ακολούθως απομονώθηκε ο υποδοχέας τρανφερρίνης στη λεϊσμάνια με χρωματογραφία συγγένειας από μεμβράνες προμαστιγωτών L.infantum. Πρόκειται για μία γλυκοπρωτεΐνη μοριακού βάρους 70kDa η οποία στερείται δισουλφιδικών δεσμών. Η μονομερής δομή του υποδοχέα επιβεβαιώθηκε με χρωματογραφία μοριακού ηθμού υψηλής πίεσης, αποτέλεσμα που υποδεικνύει την δομική διαφορά με το αντίστοιχο διμερές μόριο-υποδοχέα των κυττάρων των θηλαστικών μοριακού βάρους 170-200kDa. Επίσης με τη χρησιμοποίηση μονοκλωνικών αντισωμάτων και πολυκλωνικών αντισωμάτων που παρασκευάσθηκαν στο εργαστήριο κατά του υποδοχέα τρανφερρίνης του ανθρώπου και του αντίστοιχου υποδοχέα στη λεϊσμάνια δεν ανιχνεύθηκε αντιγονική συγγένεια μεταξύ των δύο μορίων (ραδιοανοσολογική δοκιμασία στερεής φάσης, έμμεσος ανοφοφθορισμός, ανοσοαποτύπωση σε φύλλα νιτροκυτταρίνης).Ανάλυση κατά Northern RNA των προμαστιγωτών L.infantum με χρησιμοποίηση του συμπληρωματικού DNA κλώνου TRF-2 του υποδοχέα τρανσφερρίνης του ποντικού, δεν ανέδειξε ομολογία μεταξύ των δύο γονιδίων. Πειράματα παρεμπόδισης της πρόσληψης του σιδήρου (χηλωτές σιδήρου) από τις προμαστιγωτές μορφές L.infantum και L.major έδειξαν αναστολή της ανάπτυξης των παρασίτων, αυξημένη θνησιμότητα αυτών και αυξημένη έκφραση του υποδοχέα τρανφερρίνης.Η διαπίστωση της ύπαρξης υποδοχέων τρανφερρίνης στην μεμβράνη της λεϊσμάνιας, ιδιότητα που χαρακτηρίζει τα εξελιγμένα κύτταρα των θηλαστικών, η απομόνωση του υποδοχέα της τρανσφερρίνης στη λεϊσμάνια, ο βιοχημικός και ανοσολογικός χαρακτηρισμός του μορίου καθώς και η διερεύνηση της λειτουργικής και δομικής ομοιότητάς του με τον αντίστοιχο υποδοχέα στα κύτταρα των θηλαστικών πραγματοποιήθηκε για πρώτη φορά διεθνώς κατά την εκπόνηση της παρούσας διδακτορικής διατριβής

Malaria Vaccines: From the Past towards the mRNA Vaccine Era

Plasmodium spp. is the etiological agent of malaria, a life-threatening parasitic disease transmitted by infected mosquitoes. Malaria remains a major global health challenge, particularly in endemic regions. Over the years, various vaccine candidates targeting different stages of Plasmodium parasite life-cycle have been explored, including subunit vaccines, vectored vaccines, and whole organism vaccines with Mosquirix, a vaccine based on a recombinant protein, as the only currently approved vaccine for Plasmodium falciparum malaria. Despite the aforementioned notable progress, challenges such as antigenic diversity, limited efficacy, resistant parasites escaping protective immunity and the need for multiple doses have hindered the development of a highly efficacious malaria vaccine. The recent success of mRNA-based vaccines against SARS-CoV-2 has sparked renewed interest in mRNA vaccine platforms. The unique mRNA vaccine features, including their potential for rapid development, scalability, and flexibility in antigen design, make them a promising avenue for malaria vaccine development. This review provides an overview of the malaria vaccines’ evolution from the past towards the mRNA vaccine era and highlights their advantages in overcoming the limitations of previous malaria vaccine candidates

Climate Changes Exacerbate the Spread of Ixodes ricinus and the Occurrence of Lyme Borreliosis and Tick-Borne Encephalitis in Europe&mdash;How Climate Models Are Used as a Risk Assessment Approach for Tick-Borne Diseases

Climate change has influenced the transmission of a wide range of vector-borne diseases in Europe, which is a pressing public health challenge for the coming decades. Numerous theories have been developed in order to explain how tick-borne diseases are associated with climate change. These theories include higher proliferation rates, extended transmission season, changes in ecological balances, and climate-related migration of vectors, reservoir hosts, or human populations. Changes of the epidemiological pattern have potentially catastrophic consequences, resulting in increasing prevalence of tick-borne diseases. Thus, investigation of the relationship between climate change and tick-borne diseases is critical. In this regard, climate models that predict the ticks&rsquo; geographical distribution changes can be used as a predicting tool. The aim of this review is to provide the current evidence regarding the contribution of the climatic changes to Lyme borreliosis (LB) disease and tick-borne encephalitis (TBE) and to present how computational models will advance our understanding of the relationship between climate change and tick-borne diseases in Europe

Awareness, Knowledge and Risky Behaviors of Sexually Transmitted Diseases among Young People in Greece

Sexually transmitted diseases (STDs) affect mainly young individuals and cause health, social, and economic problems worldwide. The present study used a web questionnaire to assess the awareness, knowledge, sexual behaviors, and common practices regarding STDs in young Greek adults. The 1833 individuals, aged 18–30 years, who responded to the study seem to be particularly knowledgeable regarding STDs such as AIDS (97.7%), warts (97%), Chlamydia (92.2%), genital herpes (89.9%), syphilis (81.9%), and gonorrhea (72.1%), whereas lower percentages were noted for trichomoniasis (39.3%), Molluscum contagiosum (12.9%), mycoplasmosis (11.6%), and amoebiasis (7.4%). Regarding oral STD transmission, participants replied correctly for genital herpes (45%), warts (35.8%), and AIDS (HIV; 33.8%), whereas 30.2% were unfamiliar with oral sexual transmission. Of the participants, 52% were not aware that STDs might cause infertility. Only 40.4% of the respondents reported always using condoms during sexual intercourse, and 48.6% had never been tested for STDs. The majority of the young population (55%) presented a moderate knowledge STD score (41–60%) and was associated with demographic parameters such as age, gender, sexual preference, number of sexual partners, and residence (p &lt; 0.05). These findings provide important information regarding the prevention of STDs and highlight the significance of developing more effective sex education programs for young people in Greece