ABSTRACT Oropouche virus (OROV) is reemerging in the Americas, along with a growing threat to global public health . Recent outbreaks have witnessed the first reported fatalities , vertical transmissions , and intercontinental importations of OROV, underscoring its expanding risk . Despite this, no vaccines or specific therapeutics are available, and fundamental research on OROV vaccinology and antigenicity remains limited. Here, we show that co-expression of the M polyprotein and nucleocapsid protein (NP) drives the assembly of OROV virus-like particles (VLPs) with high immunogenicity . Using the prototype strain OROV/sloth/Brazil/PA-UG-BeAn19991/1960, we developed an mRNA vaccine, M/N-vac, encoding these VLPs . Immunization with M/N-vac in mice elicited robust OROV-specific IgG and pseudovirus-neutralizing antibodies that cross-reacted with a contemporary circulating strain, hOROV/Brazil/AM-UKY-AM0088/2024. The vaccine also induced a durable, antigen-specific Th1-biased cellula...
Humoral #immunity after #LP81 monovalent #vaccines against a broad range of #SARS-CoV-2 #variants including #XEC, LP.8.1, NB.1.8.1, #XFG, and #BA32
{Excerpt} In the spring of 2025, multiple SARS-CoV-2 Omicron JN.1 subvariants were circulating, with LP.8.1 among the major variants . Pharmaceutical companies, such as Pfizer–BioNTech, Moderna, and Novavax–Takeda, adopted monovalent LP.8.1 for their 2025–26 season vaccines , following recommendations issued by WHO in May, 2025. As of November, 2025, SARS-CoV-2 variants including LP.8.1, XEC, NB.1.8.1, and XFG —all designated as variants under monitoring —were circulating. In terms of the spike gene , these variants, as well as LP.8.1, are derived from JN.1 . Moreover, BA.3.2, a BA.3 descendant bearing multiple mutations in its spike gene , has potentially been spreading and exhibiting robust immune evasion . In Japan, the roll-out of the LP.8.1-based vaccination has progressed since the end of September, 2025. We previously reported the humoral immunity induced by the XBB.1.5-based monovalent vaccine in 2023,6 and the JN.1-based monovalent vaccine in 2024 in the Japanese populat...