The evolutionary features and roles of single nucleotide variants and charged amino acid mutations in influenza outbreaks during NPI period.

The epidemic and outbreaks of influenza B Victoria lineage (Bv) during 2019-2022 led to an analysis of genetic, epitopes, charged amino acids and Bv outbreaks. Based on the National Influenza Surveillance Network (NISN), the Bv 72 strains isolated during 2019-2022 were selected by spatio-temporal sampling, then were sequenced. Using the Compare Means, Correlate and Cluster, the outbreak data were analyzed, including the single nucleotide variant (SNV), amino acid (AA), epitope, evolutionary rate (ER), Shannon entropy value (SV), charged amino acid and outbreak. With the emergence of COVID-19, the non-pharmaceutical interventions (NPIs) made Less distant transmission and only Bv outbreak. The 2021-2022 strains in the HA genes were located in the same subset, but were distinct from the 2019-2020 strains (P < 0.001). The codon G → A transition in nucleotide was in the highest ratio but the transversion of C → A and T → A made the most significant contribution to the outbreaks, while the increase in amino acid mutations characterized by polar, acidic and basic signatures played a key role in the Bv epidemic in 2021-2022. Both ER and SV were positively correlated in HA genes (R = 0.690) and NA genes (R = 0.711), respectively, however, the number of mutations in the HA genes was 1.59 times higher than that of the NA gene (2.15/1.36) from the beginning of 2020 to 2022. The positively selective sites 174, 199, 214 and 563 in HA genes and the sites 73 and 384 in NA genes were evolutionarily selected in the 2021-2022 influenza outbreaks. Overall, the prevalent factors related to 2021-2022 influenza outbreaks included epidemic timing, Tv, Ts, Tv/Ts, P137 (B → P), P148 (B → P), P199 (P → A), P212 (P → A), P214 (H → P) and P563 (B → P). The preference of amino acid mutations for charge/pH could influence the epidemic/outbreak trends of infectious diseases. Here was a good model of the evolution of infectious disease pathogens. This study, on account of further exploration of virology, genetics, bioinformatics and outbreak information, might facilitate further understanding of their deep interaction mechanisms in the spread of infectious diseases.

Artesunate alleviates imiquimod-induced psoriasis-like dermatitis in BALB/c mice.

Artesunate (ART), a derivative of artemisinin, is a medication to treat malaria. Beyond that, the anti-inflammatory and immunoregulatory activities of ART have been identified in autoimmune diseases. However, whether ART functions in psoriasis-like dermatitis induced by imiquimod (IMQ, a TLR7/8 agonist) is currently unkown. There, we found that the cumulative score, epidermal thickening and expression of Ki-67 of ART-treated BALB/c mice were significantly lower than those in the IMQ psoriatic model group. In addition, ART treatment ameliorated mice from systemic inflammation. Mechanistically, ART reduced γδ T cells in draining lymph nodes, which might be benefit the improvement of dermatitis. These findings suggested that ART could be a promising drug of psoriasis in clinic.

Charged amino acid variability related to N-glyco -sylation and epitopes in A/H3N2 influenza: Hem -agglutinin and neuraminidase.

BACKGROUND: The A/H3N2 influenza viruses circulated in humans have been shown to undergo antigenic drift, a process in which amino acid mutations result from nucleotide substitutions. There are few reports regarding the charged amino acid mutations. The purpose of this paper is to explore the relations between charged amino acids, N-glycosylation and epitopes in hemagglutinin (HA) and neuraminidase (NA). METHODS: A total of 700 HA genes (691 NA genes) of A/H3N2 viruses were chronologically analyzed for the mutational variants in amino acid features, N-glycosylation sites and epitopes since its emergence in 1968. RESULTS: It was found that both the number of HA N-glycosylation sites and the electric charge of HA increased gradually up to 2016. The charges of HA and HA1 increased respectively 1.54-fold (+7.0 /+17.8) and 1.08-fold (+8.0/+16.6) and the number of NGS in nearly doubled (7/12). As great diversities occurred in 1990s, involving Epitope A, B and D mutations, the charged amino acids in Epitopes A, B, C and D in HA1 mutated at a high frequency in global circulating strains last decade. The charged amino acid mutations in Epitopes A (T135K) has shown high mutability in strains near years, resulting in a decrease of NGT135-135. Both K158N and K160T not only involved mutations charged in epitope B, but also caused a gain of NYT158-160. Epitope B and its adjacent N-glycosylation site NYT158-160 mutated more frequently, which might be under greater immune pressure than the rest. CONCLUSIONS: The charged amino acid mutations in A/H3N2 Influenza play a significant role in virus evolution, which might cause an important public health issue. Variability related to both the epitopes (A and B) and N-glycosylation is beneficial for understanding the evolutionary mechanisms, disease pathogenesis and vaccine research.

A humoral immunity survey following the 2012 influenza season after the pH1N1 pandemic in Guangzhou, China.

According to pathogenic surveillance data during the first half of 2012, the H3N2 influenza virus was prevalent in Guangdong, China, but no pandemic H1N1 (pH1N1) virus was detected. This study aimed to measure the seroprevalence of pH1N1 and H3N2 infection following the influenza epidemic in 2012. We collected serum samples by stratified random sampling in a cross-sectional survey from August, 2012 to October, 2012. Antibody titers against H3N2, pH1N1, and influenza B antigens were measured by the hemagglutination inhibition (HI) assay, and age-specific seroprevalence and non-immunity were calculated. A total of 566 serum samples were collected from subjects who had not received an influenza vaccination. The seroprevalence of H3N2, pH1N1, and influenza B were 61.7%, 31.3%, and 40.4%, respectively, while non-immunity was calculated to be 9.2%, 40.6%, and 27.0%, respectively. The highest recorded seroprevalence was 86.0% for H3N2 in the 6-15 year age group, while the lowest was 14.6% for pH1N1 in the 60+ age group. Non-immunity fractions were 44.4% and 53.5% in the 0-6 and 60+ age groups, respectively. In conclusion, the seroprevalence of pH1N1 remained below 50% in all age groups following the 2012 influenza season. These data suggest that vaccination against pH1N1 antigens should be conducted, especially in the older age groups, before the next influenza season.