RESUMO
In this study we detail the detection and genetic analysis of a novel porcine boca-like virus (PBo-likeV) in archival sera and tissue samples from pigs from farms in Great Britain. We also investigate the distribution of porcine circovirus type 2 (PCV2) genotypes and Torque teno sus virus (TTSuV) genogroups 1 and 2 in combination with this novel PBo-likeV. PBo-likeV was detected in over 70% of all tissues investigated. Over 24% of all tissues recovered from PMWS-affected animals had all viruses present and 25% of tissues recovered from non-PMWS-affected pigs were positive for all 4 viruses.
Assuntos
Infecções por Vírus de DNA/veterinária , Vírus de DNA/fisiologia , Doenças dos Suínos/epidemiologia , Doenças dos Suínos/virologia , Animais , Bocavirus/classificação , Bocavirus/genética , Bocavirus/fisiologia , Circovirus/classificação , Circovirus/genética , Circovirus/fisiologia , Infecções por Vírus de DNA/epidemiologia , Infecções por Vírus de DNA/virologia , Vírus de DNA/classificação , Vírus de DNA/genética , DNA Viral/genética , Genótipo , Dados de Sequência Molecular , Filogenia , Suínos , Torque teno virus/classificação , Torque teno virus/genética , Torque teno virus/fisiologia , Reino Unido/epidemiologia , Proteínas do Core Viral/genéticaRESUMO
Immunoreactive T lymphocyte epitopes within the ORF1, ORF2, and ORF 3 products of porcine circovirus type 2 (PCV2) were mapped. For this, overlapping linear 20-mer peptides were synthesized and tested for their ability to induce T lymphocyte proliferation in porcine peripheral blood mononuclear cells (PBMCs) isolated from experimentally PCV2-infected pigs. After a preliminary screening of 31 (ORF1), 23 (ORF2), and 10 (ORF3) peptides using PBMCs from 4 PCV2-infected pigs, none of the peptides appeared to be immunoreactive (stimulation index [SI] : 2) in all four pigs. Only 14 peptides appeared to be immunoreactive in 3 of the 4 pigs. These peptides were designated as immunodominant in the preliminary screening and selected for further analysis. The immunodominant peptides were resynthesized and purified by high-performance liquid chromatography and tested for their ability to induce T lymphocyte proliferation in PBMCs from another three PCV2-infected pigs. None of the immunodominant peptides appeared to be immunoreactive in all three pigs of the second screening. Only three peptides appeared to be immunoreactive in two of three pigs, two encoded by PCV2 ORF1 (amino acid residues 81-100 and 201-220) and one encoded by PCV2 ORF3 (amino acid residues 31-50), and were therefore considered to be immunodominant in both screenings. Although peptides encoded by ORF2 appeared to show the highest immunoreactivity in some pigs, none of these peptides displayed immunodominance in both screenings. In summary, the present study indicates that the T lymphocyte responses to PCV2 are primarily directed toward epitopes of the nonstructural proteins of ORF1 and ORF3.
Assuntos
Circovirus/imunologia , Mapeamento de Epitopos , Epitopos de Linfócito T/imunologia , Animais , Proliferação de Células , Células Cultivadas , Epitopos Imunodominantes/imunologia , Leucócitos Mononucleares , Ativação Linfocitária , Peptídeos/síntese química , Peptídeos/imunologia , Suínos , Proteínas Virais/imunologiaRESUMO
A panel of 20 porcine sera was distributed to 5 laboratories across Europe and Canada. Each center was requested to test the sera for the presence of porcine circovirus type 2 antibodies using the routine assays, indirect immunofluorescence assay (IFA) and indirect immunoperoxidase monolayer assay (IPMA), and to determine the titer of each serum. Results from all centers were then compiled and correlated. They demonstrate a wide variation in the titers obtained between laboratories. These differences were dependent on the assay used and the choice of fixative. In general, IPMA gave higher titers than did IFA, and paraformaldehyde gave higher titers than did acetone or ethyl alcohol. This report highlights the need for standardized procedures and biologicals for this virus.