A Sendai virus-derived RNA agonist of RIG-I as a virus vaccine adjuvant.

The innate immune system is responsible for recognizing invading pathogens and initiating a protective response. In particular, the retinoic acid-inducible gene 1 protein (RIG-I) participates in the recognition of single- and double-stranded RNA viruses. RIG-I activation leads to the production of an appropriate cytokine and chemokine cocktail that stimulates an antiviral state and drives the adaptive immune system toward an efficient and specific response against the ongoing infection. One of the best-characterized natural RIG-I agonists is the defective interfering (DI) RNA produced by Sendai virus strain Cantell. This 546-nucleotide RNA is a well-known activator of the innate immune system and an extremely potent inducer of type I interferon. We designed an in vitro-transcribed RNA that retains the type I interferon stimulatory properties, and the RIG-I affinity of the Sendai virus produced DI RNA both in vitro and in vivo. This in vitro-synthesized RNA is capable of enhancing the production of anti-influenza virus hemagglutinin (HA)-specific IgG after intramuscular or intranasal coadministration with inactivated H1N1 2009 pandemic vaccine. Furthermore, our adjuvant is equally effective at increasing the efficiency of an influenza A/Puerto Rico/8/34 virus inactivated vaccine as a poly(I·C)- or a squalene-based adjuvant. Our in vitro-transcribed DI RNA represents an excellent tool for the study of RIG-I agonists as vaccine adjuvants and a starting point in the development of such a vaccine.

[Translated article] Necrotising fasciitis: Management experience over the last two decades in our hospital.

BACKGROUND: Necrotising fasciitis is a potentially life-threatening soft tissue infection that mainly affects the fascia and deep planes, with a very high mortality rate and severe related complications. AIM: To evaluate clinical and demographic characteristics of patients with necrotising fasciitis in our hospital and to describe their diagnostic and therapeutic management. MATERIAL AND METHODS: Retrospective review of medical records of 21 patients diagnosed with necrotising fasciitis with limb involvement between January 2003 and February 2021 in our hospital. Demographic data, clinical features and details of management and prognosis were collected for each patient. RESULTS: Of 21 patients included, 15 were male (71.43%), with a mean age at diagnosis of 54.38±19.55 years. The most frequent comorbidities were insulin-dependent diabetes mellitus in seven patients (33.33%) and a history of cancer in five patients (23.81%). Infection was monomicrobial in 14 cases (66.66%), with Streptococcus pyogenes being the most frequent microorganism; multiple pathogens were isolated in 2 patients (9.52%) and no microorganism was identified in 5 patients (23.81%). All patients underwent surgery at our hospital, with a mean of 4.14±3.98 surgeries. Only one patient underwent amputation of the affected limb. The mean hospital stay was 23.14±16.44 days, with an overall mortality of 47.62% (10 cases). CONCLUSIONS: Despite being a rare disease, necrotising fasciitis is a very aggressive pathology, with a high mortality rate, especially in immunocompromised patients. Advanced age and oncological disease are potential factors of worse prognosis in the evolution of this condition.

RNA-binding properties and membrane insertion of Melon necrotic spot virus (MNSV) double gene block movement proteins.

Advances in structural and biochemical properties of carmovirus movement proteins (MPs) have only been obtained in p7 and p9 from Carnation mottle virus (CarMV). Alignment of carmovirus MPs revealed a low conservation of amino acid identity but interestingly, similarity was elevated in regions associated with the functional secondary structure elements reported for CarMV which were conserved in all studied proteins. Nevertheless, some differential features in relation with CarMV MPs were identified in those from Melon necrotic virus (MNSV) (p7A and p7B). p7A was a soluble non-sequence specific RNA-binding protein, but unlike CarMV p7, its central region alone could not account for the RNA-binding properties of the entire protein. In fact, a 22-amino acid synthetic peptide whose sequence corresponds to this central region rendered an apparent dissociation constant (K(d)) significantly higher than that of the corresponding entire protein (9 mM vs. 0.83-25.7 microM). This p7A-derived peptide could be induced to fold into an alpha-helical structure as demonstrated for other carmovirus p7-like proteins. Additionally, in vitro fractionation of p7B transcription/translation mixtures in the presence of ER-derived microsomal membranes strongly suggested that p7B is an integral membrane protein. Both characteristics of these two small MPs forming the double gene block (DGB) of MNSV are discussed in the context of the intra- and intercellular movement of carmovirus.