Glicoproteína del virus rábico: Estructura, inmunogenicidad y rol en la patogenia / Rabies vims glycoprotein: Structure, immunogenicity and pathogenic role

Rabies glycoprotein is the only exposed protein which is inserted in the viral lipidie envelope. This 65-67 kda protein is a N-glycosilated transmembrane protein forming trimers on the viral surface. It has been identified as the major pathogenicity determinant, playing a role in the budding, viral axonal transport during infection, apoptosis and immune evasion. It is also the major antigen responsible for the protective immune response and it is been used in commercial recombinant vaccines. Its structure, antigenicity and pathogenic role have been well studied, identifying main antigenic sites that have the responsibility for virulence, cellular receptors attachment and epitope acquisition.

La glicoproteína del virus rábico es la única proteína viral expuesta, encontrándose inserta en la envoltura lipídica. Esta molécula de 65-67 kda corresponde a una proteína trans-membrana N-glicosilada que se dispone en forma de trímeros en la superficie viral. Ha sido identificada como el mayor determinante de pato-genicidad, participando además en procesos de yemación, flujo axonal del virion durante la infección, apoptosis y evasión de la respuesta inmune. Es también el principal antígeno inductor de la respuesta inmune protectora siendo utilizado en vacunas recom-binantes comerciales. Su estructura, antigenicidad e implicancias en la patogenia han sido bien estudiadas identificándose los principales sitios antigénicos responsables de la patogenicidad, unión a receptores celulares y formación de epitopos.

Hydrophilicity and antigenicity of proteins—A case study of myoglobin and hemoglobin.

Hydrophilicity index is used to locate antigenic determinants on two related groups of proteins—myoglobin and hemoglobin. The data on 41 species (including 34 mammals) of myoglobin show that average hydrophilicity for the complete myoglobin molecules as well as the average hydrophilicity for all hydrophilic regions put together seem to remain constant; the variation in the size and location of the antigenic determinants in these species is very small indicating that the antigenic sites are not shifted during evolution. In the case of both the proteins there is a good agreement between the antigenic sites picked up by using hydrophilicity index and the experimentally determined antigenic sites. The data on 56 species of hemoglobin α-chains and 44 species of hemoglobin β-chains showed that although there are few sites on hemoglobin which have remained invariant during evolution, there is a significant variation in other sites in terms of either a splitting of a site, or a drastic change in the hydrophilicity values and/or a length of the site. Comparison of the hydrophilicity data on these two groups of proteins suggests that hemoglobins which perform a variety of functions as compared to myoglobins are evolving faster than myoglobins supporting the contention of earlier workers.

Theoretical prediction of antigenic sites in the ß-subunits of human choriogonadotropin and luteinizing hormone.

Using hydrophilicity and recognition values of amino acids, the antigenic sites of the β-subunits of human choriogonadotropin and luteinizing hormone were computed from their amino acid sequences. Six antigenic sites were calculated for human choriogonadotropin ßsubunits: residues 3–8, 17–22, 59–65,100–106,110–116 and 134–139. For luteinizing hormone β-chain three antigenic sites were calculated: residues 17–22,59–65, and 100–106; all these three sites of luteinizing hormone β being identical to the corresponding sites in human choriogonadotropin β. There was no antigenic site in luteinizing hormone that was also not found in human choriogonadotropin. On the other hand, there were unique determinants in human choriogonadotropin that were not found in luteinizing hormone; these determinants were residues 3–8, 110–116 and 134–139.