Disease relevance of Influenzavirus C

• Human and bovine coronaviruses recognize sialic acid-containing receptors similar to those of influenza C viruses [1].
• These results strongly suggest that the surface glycoprotein of influenza C virus is structurally much more stable than the haemagglutinin and neuraminidase glycoproteins of influenza A and B viruses [2].
• The HA of influenza B virus contains mainly palmitic acid, whereas the HEF glycoprotein of influenza C virus is acylated with stearic acid which has not been observed before as the prevailing fatty acid in viral or cellular acyl proteins [3].
• Five strains of influenza C virus were isolated and passaged in the amniotic sacs of embryonated hens' eggs, or in the HMV-II line of human malignant melanoma cells, and were tested for reactivity with a panel of monoclonal antibodies to the hemagglutinin-esterase (HE) glycoprotein [4].
• The CM2 coding region of RNA segment 6 (nucleotides 731-1147) was cloned from two strains of influenza C virus and expressed using the vaccinia virus-bacteriophage T7 RNA polymerase (vac-T7) system [5].

High impact information on Influenzavirus C

• Structure of the haemagglutinin-esterase-fusion glycoprotein of influenza C virus [6].
• The influenza C virus (INF-C) hemagglutinin recognizes 9-O-acetyl-N-acetylneuraminic acid [7].
• Using a recombinant soluble form of the Influenza C virus hemagglutinin-esterase as a probe for 9-O-acetylated sialic acids, we demonstrate here their preferential expression on the CD4 T cell lineage in normal B10.A mouse lymphoid organs [8].
• The data also indicate that haemagglutination-inhibition (HI) by RMG and BSM and most likely virus attachment to cell surfaces involves binding of influenza C virus to Neu5,9Ac2 [9].
• H.p.l.c. analysis revealed that purified Neu5,9Ac2 is converted to Neu5Ac by incubation with influenza C virus [9].

Chemical compound and disease context of Influenzavirus C

• By contrast, the phosphorothioate derivatives (S-ODNs) were found to inhibit replication of both influenza A and influenza C virus [10].
• We therefore studied the effects of the arginine-specific modifying reagents 2,3-butanedione and phenylglyoxal on 9-O-Ac-SA esterase activities from influenza C virus, human erythrocytes, rat liver, starfish gonads, and sea bass brain [11].
• Additional evidence that RNA 4 of influenza C virus codes for the hemagglutinin is that the tripeptide Ile-Phe-Gly, known to be present at the amino terminus of the hemagglutinin 2 subunit of influenza C virus, is encoded by RNA 4 at a point immediately adjacent to the presumptive arginine cleavage site [12].
• Inhibition of influenza C virus replication by actinomycin D, alpha-amanitin, and UV irradiation [13].
• Furthermore, we found that the influenza C virus esterase was inhibited by isocoumarin derivatives, with 3,4-dichloroisocoumarin being the most potent inhibitor [14].

Biological context of Influenzavirus C

• The hemagglutinin, esterase, and fusion (HEF) glycoprotein of influenza C virus possesses receptor binding, receptor destroying, and membrane fusion activities [15].
• Sera from persons of four age groups (1 to 2 years, 2 to 5 years, 20 to 30 years, and 65 to 85 years) were analyzed for hemagglutination inhibition (HI) activity for influenza C virus [16].
• The three large RNA segments of influenza C virus C/JJ/50 were cloned and sequenced, and the deduced amino acid sequences were compared with those of the polymerase (P) proteins of influenza A and B viruses [17].
• Antigenic variation among influenza C virus strains was investigated with monoclonal antibodies against gp88 glycoprotein [18].
• Serine 71 of the glycoprotein HEF is located at the active site of the acetylesterase of influenza C virus [19].

Anatomical context of Influenzavirus C

• Immunofluorescence analysis with the monoclonal antibodies revealed that both the NP and M proteins migrated to the cell nucleus during the replication cycle of influenza C virus [20].
• To demonstrate the ion channel activity of Influenza C virus CM2, we expressed this protein in oocytes of Xenopus laevis and measured whole cell currents by a two-electrode voltage-clamp method [21].

Gene context of Influenzavirus C

• RNA segment 1 of influenza C virus encodes the equivalent of the PB2 protein; it has an approximate 25% sequence identity with the corresponding (cap binding) influenza A and B virus PB2 proteins [17].
• This protein is thus referred to as the P3 (rather than the PA) protein of influenza C virus [17].
• Identification of an amino acid residue on influenza C virus M1 protein responsible for formation of the cord-like structures of the virus [22].
• Phylogenetic analysis of influenza C virus nonstructural (NS) protein genes and identification of the NS2 protein [23].
• It was found that the colinear mRNA derived from influenza C virus RNA segment 6 serves as the mRNA for CM2 [24].

Analytical, diagnostic and therapeutic context of Influenzavirus C

• Evidence was obtained by electron microscopy that transfected cells bearing cords produced filamentous VLPs, suggesting the potential role of the M1 protein in determining the filamentous/spherical morphology of influenza C virus [22].
• Using SDS polyacrylamide gel electrophoresis and one-dimensional peptide mapping we found the virus-coded proteins of the pig influenza C viruses to be similar to those of human influenza C virus strains [25].

References