RESUMO
The sialidase protein is a major part of hemagglutinin-neuraminidase (HN) protein of Newcastle disease virus (NDV), which is an important multifunctional envelope protein. This protein plays key roles in virus attachment to cells and virus-cell fusion. In this study, we compared the sialidase protein of Iranian virulent velogenic field strains with that of avirulent lentogenic strains. Six of seventeen variations in amino acid 395, 523, 550 432, 479 and 540 were observed near the catalytic and glycosylation sites in the sialidase protein. The obtained results showed fundamental differences in various biological parameters such as post-translational modification, antigenic index and electrostatic potential of tertiary structure of the sialidase protein. We suggest these six amino acids might play an effective role in the pathogenesis of NDV.
Assuntos
Neuraminidase/genética , Doença de Newcastle/virologia , Vírus da Doença de Newcastle/enzimologia , Doenças das Aves Domésticas/virologia , Proteínas Virais/genética , Sequência de Aminoácidos , Animais , Galinhas , Modelos Moleculares , Dados de Sequência Molecular , Neuraminidase/química , Neuraminidase/metabolismo , Vírus da Doença de Newcastle/química , Vírus da Doença de Newcastle/genética , Vírus da Doença de Newcastle/patogenicidade , Alinhamento de Sequência , Proteínas Virais/química , Proteínas Virais/metabolismo , VirulênciaRESUMO
In a previous paper, we have noticed the effectiveness of two further attenuated measles vaccines, i.e. AIK-HDC and Edmonston- Zagreb- HDC. In the present study the same strains are comparatively used for immunization of a limited number of children under 9 months of age. A seroconversion of 100% was observed. Following reimmunization, a significant increase of circulating antibodies for both strains was recorded. Two combined measles-mumps-rubella (MMR) vaccines were also produced by using the same measles strains. The seroconversion following utilisation of MMR prophylactics in susceptible children was 98.8 and 97.3 for AIK and Edmonston- Zagreb strains respectively.
Assuntos
Vacina contra Sarampo/imunologia , Vírus do Sarampo/classificação , Vacina contra Caxumba/imunologia , Vacina contra Rubéola/imunologia , Anticorpos Antivirais/biossíntese , Pré-Escolar , Combinação de Medicamentos , Estudos de Avaliação como Assunto , Feminino , Humanos , Imunização , Lactente , Masculino , Vírus do Sarampo/imunologia , Vacina contra Sarampo-Caxumba-Rubéola , Vírus da Caxumba/imunologia , Vírus da Rubéola/imunologia , Vacinas Atenuadas/imunologiaRESUMO
Two live attenuated measles vaccines developed in baby calf kidney cells, a similar vaccine produced in chick embryo chorioallantoic cells and five vaccines prepared from human diploid cells (HDC) have been studied by subcutaneous injection in groups of susceptible and immune children in three field trials. The results indicated that the vaccine developed in chick embryo cells which caused mild clinical reactions, had induced a lower seroprotection rate in susceptible children and only a low rise in hemagglutination-inhibition (HI) antibody titre in previously immunized children. The serological responses induced by vaccines developed in HDC or in calf kidney cells were satisfactory in both susceptible and immune children. The superiority of HDC grown measles vaccine for revaccination is discussed.