Vaccination against SARS-CoV-2 provides low-level cross-protection against common cold coronaviruses in mouse and non-human primate animal models.

The common cold coronaviruses are a source of ongoing morbidity and mortality particularly among elderly and immunocompromised individuals. While cross-reactive immune responses against multiple coronaviruses have been described following severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination, it remains unclear if these confer any degree of cross-protection against the common cold coronaviruses. A recombinant fowl adenovirus vaccine expressing the SARS-CoV-2 spike protein (FAdV-9-S19) was generated, and protection from SARS-CoV-2 challenge was shown in K18-hACE2 mice.

Comparison of a SARS-CoV-2 mRNA booster immunization containing additional antigens to a spike-based mRNA vaccine against Omicron BA.5 infection in hACE2 mice.

The emergence of SARS-CoV-2 variants presents challenges to vaccine effectiveness, underlining the necessity for next-generation vaccines with multiple antigens beyond the spike protein. Here, we investigated a multiantigenic booster containing spike and a chimeric construct composed of nucleoprotein (N) and membrane (M) proteins, comparing its efficacy to a spike-only booster against Omicron BA.5 in K18-hACE2 mice.

Streptolysin S is required for Streptococcus pyogenes nasopharyngeal and skin infection in HLA-transgenic mice.

Streptococcus pyogenes is a human-specific pathogen that commonly colonizes the upper respiratory tract and skin, causing a wide variety of diseases ranging from pharyngitis to necrotizing fasciitis and toxic shock syndrome. S. pyogenes has a repertoire of secreted virulence factors that promote infection and evasion of the host immune system including the cytolysins streptolysin O (SLO) and streptolysin S (SLS).

Longitudinal Analysis of Mpox Virus DNA Detectability From Multiple Specimen Types During Acute Illness: A Cohort Study.

Background: Longitudinal data on the detectability of monkeypox virus (MPXV) genetic material in different specimen types are scarce.

Methods: We describe MPXV-specific polymerase chain reaction (PCR) results from adults with confirmed mpox infection from Toronto, Canada, including a cohort undergoing weekly collection of specimens from multiple anatomic sites until 1 week after skin lesions had fully healed. We quantified the time from symptom onset to resolution of detectable viral DNA (computed tomography [Ct] ≥ 35) by modeling exponential decay in Ct value as a function of illness day for each site, censoring at the time of tecovirimat initiation.

The Streptococcus pyogenes hyaluronic acid capsule promotes experimental nasal and skin infection by preventing neutrophil-mediated clearance.

Streptococcus pyogenes is a globally prominent human-specific pathogen responsible for an enormous burden of human illnesses, including >600 million pharyngeal and >100 million skin infections each year. Despite intensive efforts that focus on invasive indications, much remains unknown about this bacterium in its natural state during colonization of the nasopharynx and skin. Using acute experimental infection models in HLA-transgenic mice, we evaluated how the hyaluronic acid (HA) capsule contributes to S.

Streptococcal superantigens and the return of scarlet fever.

Streptococcus pyogenes (group A Streptococcus) is a globally disseminated and human-adapted bacterial pathogen that causes a wide range of infections, including scarlet fever. Scarlet fever is a toxin-mediated disease characterized by the formation of an erythematous, sandpaper-like rash that typically occurs in children aged 5 to 15. This infectious disease is caused by toxins called superantigens, a family of highly potent immunomodulators.

Streptococcal pharyngitis and rheumatic heart disease: the superantigen hypothesis revisited.

Streptococcus pyogenes is a human-specific and globally prominent bacterial pathogen that despite causing numerous human infections, this bacterium is normally found in an asymptomatic carrier state. This review provides an overview of both bacterial and human factors that likely play an important role in nasopharyngeal colonization and pharyngitis, as well as the development of acute rheumatic fever and rheumatic heart disease. Here we highlight a recently described role for bacterial superantigens in promoting acute nasopharyngeal infection, and discuss how these immune system activating toxins could be crucial to initiate the autoimmune process in rheumatic heart disease.