RESUMO
Hendra virus (HeV) is a recently identified paramyxovirus that is fatal in humans and could be used as an agent of bioterrorism. The HeV receptor-binding protein (G) is required in order for the fusion protein (F) to mediate fusion, and analysis of the triggering/activation of HeV F by G should lead to strategies for interfering with this key step in viral entry. HeV F, once triggered by the receptor-bound G, by analogy with other paramyxovirus F proteins, undergoes multistep conformational changes leading to a six-helix bundle (6HB) structure that accomplishes fusion of the viral and cellular membranes. The ectodomain of paramyxovirus F proteins contains two conserved heptad repeat regions (HRN and HRC) near the fusion peptide and the transmembrane domains, respectively. Peptides derived from the HRN and HRC regions of F are proposed to inhibit fusion by preventing F, after the initial triggering step, from forming the 6HB structure that is required for fusion. HeV peptides have previously been found to be effective at inhibiting HeV fusion. However, we found that a human parainfluenza virus 3 F-peptide is more effective at inhibiting HeV fusion than the comparable HeV-derived peptide.
Assuntos
Vírus Hendra/fisiologia , Sequência de Aminoácidos , Fusão Celular , Linhagem Celular , Humanos , Modelos Moleculares , Dados de Sequência Molecular , Mutação/genética , Fragmentos de Peptídeos/metabolismo , Estrutura Terciária de Proteína , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/genética , Proteínas Virais de Fusão/metabolismo , Vírion/metabolismoRESUMO
The relationship between cytomegalovirus titers and immunoglobulin (Ig) levels in 514 paired maternal-fetal sera at term was studied. Positive cytomegalovirus titers were found in 192 (37.4%) maternal sera and 138 (26.8%) fetal sera. Fetal sera with positive cytomegalovirus titers had decreased IgM levels, and maternal sera with positive cytomegalovirus titers had increased IgG levels. There was a negative correlation between cytomegalovirus titer level and IgM concentration in fetal serum and a positive correlation between cytomegalovirus titers levels and IgG concentration in maternal serum in individual samples. After removal of IgG from samples with cytomegalovirus positive titers by column chromatography, 17 maternal and 22 fetal sera remained cytomegalovirus positive.
