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Reinfections with SARS-CoV-2 have already been documented in humans, although its real incidence is currently unknown. Besides having a great impact on public health, this phenomenon raises the question of immunity generated by a single infection is sufficient to provide sterilizing/protective immunity to a subsequent SARS-CoV-2 re-exposure. The Golden Syrian hamster is a manageable animal model to explore immunological mechanisms able to counteract COVID-19, as it recapitulates pathological aspects of mild to moderately affected patients. Here, we report that SARS-CoV-2-inoculated hamsters resolve infection in the upper and lower respiratory tracts within seven days upon inoculation with the Cat01 (G614) SARS-CoV-2 isolate. Three weeks after the primary challenge, and despite high titres of neutralizing antibodies, half of the animals were susceptible to reinfection by both identical (Cat01, G614) and variant (WA/1, D614) SARS-CoV-2 isolates. However, upon re-inoculation, only nasal tissues were transiently infected with much lower viral replication than those observed after the first inoculation. These data indicate that a primary SARS-CoV-2 infection is not sufficient to elicit a sterilizing immunity in hamster models but protects against lung disease.
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http://dx.doi.org/10.1080/22221751.2021.1913974 | DOI Listing |
BMC Oral Health
September 2025
Department of Craniomaxillofacial Plastic and Cosmetic Center, Hospital of Stomatology, Jilin University, No.1500 Qinghua Road, Changchun, Jilin, 130021, China.
Background: It has been reported that CD4 + helper T cells, such as Th1, Th2, Th17 and Treg, play crucial roles in the immunological balance especially when the immune system is invaded by the tumor. Oral squamous cell carcinoma undergoes a process from normal epithelium to dysplasia. However, the dynamic equilibrium of Th1/Th2 and Th17/Treg remained unclear during the process of epithelial malignant transformation.
View Article and Find Full Text PDFMol Ther Nucleic Acids
September 2025
Center for RNA Biology and Therapeutics, Beckman Research Institute of the City of Hope, Duarte, CA, USA.
Front Microbiol
August 2025
Unitat Mixta d'Investigació IRTA-UAB en Sanitat Animal, Centre de Recerca en Sanitat Animal (CReSA), Campus de la Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain.
Introduction: Post-COVID-19 condition (PCC) is a long-lasting, multisystemic syndrome affecting approximately 30% of individuals after acute COVID-19, with neurological symptoms among the most prevalent and debilitating. Despite its substantial global health impact, the biological mechanisms underlying PCC remain poorly understood, underscoring the need for validated animal models.
Methods: To address this, we conducted a longitudinal study using the golden Syrian hamster model, integrating virological, immunological, histopathological, and behavioral analyses from the acute phase to 60 days post-inoculation.
The first generation of Spike-based COVID-19 vaccines has reduced the risk of hospitalization, serious illness, and death caused by SARS-CoV-2 infections. However, waning immunity induced by these vaccines has failed to prevent immune escape, resulting in the emergence of multiple variants of concern (VOCs) and the prolongation of the COVID-19 pandemic. We hypothesize that a next-generation Coronavirus (CoV) vaccine incorporating highly conserved SARS-CoV-2 T cell antigens would confer potent, broad, and long-lasting cross-protective immunity against multiple VOCs.
View Article and Find Full Text PDFJ Helminthol
September 2025
G.P. Somov Research Institute of Epidemiology and Microbiology, Russian Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeing (Rospotrebnadzor), Russian Federation.
Adult trematodes of two species of the genus were found in the southern Far East of Russia: one species in the intestine of a naturally infected Japanese large-footed bat () and the other in a golden hamster () experimentally infected with metacercariae collected from a stonefly. On the basis of morphological and molecular studies, the trematode individuals found in the bat were identified as , which confirms that this species is cosmopolitan. The trematodes reared in the hamster were similar in their morphological features to the European However, due to the lack of nucleotide sequences for this species from the type region, the southern Far East of Russia trematodes, found in this study, were provisionally designated as In addition, the phylogenetic reconstruction based on a mitochondrial marker revealed inconsistency of the data obtained from cercariae diagnosed as a single species, Our data also indicate that the specimens available in the NCBI database referred to as and belong to the same species.
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