Infection by enveloped viruses is initiated by the fusion of viral and cellular membranes. In many cases, the viral membrane proteins that mediate fusion must undergo conformational changes to become active. Influenza hemagglutinin, for example, is activated by a dramatic conformational rearrangement, triggered by the low pH of the intracellular compartment in which fusion occurs. Structural ch...

Influenza viruses possess at their surface two glycoproteins, the hemagglutinin and the neuraminidase, of which the antagonistic functions have to be well balanced for the virus to grow efficiently. Ferraris et al. isolated in 2003-2004 viruses lacking both a NA gene and protein (H3NA- viruses) (Ferraris O., 2006, Vaccine, 24(44-46):6656-9). In this study we showed that the hemagglutinins of tw...

The influenza hemagglutinin is a critical regulator of disease expression during influenza virus infection and serves as a major target for the host immune response to this pathogen. In this report, we have analyzed an immunodominant site on the hemagglutinin (residues 202-221) recognized by murine class I MHC-restricted T lymphocytes. This analysis has revealed evidence for the duplication of ...

Chikungunya virus vaccines prepared by Tween 80 and ether inactivation of virus grown in green monkey kidney cell cultures were shown to be as immunogenic as comparable Formalin-inactivated vaccines. Both types of vaccine stimulated hemagglutination-inhibiting, complement-fixing, and neutralizing antibody and afforded protection to mice against a live virus challenge. It was shown after Tween-e...

We examined the distribution of selected raft proteins on the sarcolemma of skeletal myofibers and the role of cholesterol environment in the distribution. Immunofluorescence staining showed that flotillin-1 and influenza hemagglutinin exhibited rafts that located in the domains deficient of the dystrophin glycoprotein complex, but the distribution patterns of the two proteins were different. C...

This study examined the phylogenetic relationship of strains of canine distemper virus (CDV) collected from Paraná State, Brazil, based on the hemagglutinin gene. Urine samples were collected from 4 dogs from northern Paraná State that demonstrated clinical manifestations of canine distemper. The participation of CDV was initially confirmed by RT-PCR targeting the nucleocapsid protein, after wh...

Current inactivated influenza vaccines provide protection when vaccine antigens and circulating viruses share a high degree of similarity in hemagglutinin protein. Five antigenic sites in the hemagglutinin protein have been proposed, and 131 amino acid positions have been identified in the five antigenic sites. In addition, 20, 18, and 32 amino acid positions in the hemagglutinin protein have b...