ABSTRACT
Viral DNA subpopulations were produced when the ASFV was grown in monkey kidney MS cells. They were detected after 44 passages but not during the first 14 passages or in the unadapted ASFV E 70 strain grown in pig leukocytes. Different viral variants were isolated and their genomes were characterized. Restriction enzyme site variations were detected in both terminal fragments, Cla I-M and Sal I-F, and in the internal fragments Clal-O and Sma I-H. These variations result in changes in the size of the viral genome which ranges from 156 Kbp to 170 Kbp.
Subject(s)
African Swine Fever Virus/genetics , DNA, Viral/genetics , Iridoviridae/genetics , African Swine Fever Virus/growth & development , Animals , Cell Line , Cloning, Molecular , DNA Restriction Enzymes , Haplorhini , KidneyABSTRACT
Restriction enzyme cleavage maps for the fragments produced by Cla I, Sal I and Sma I have been constructed for African swine fever virus (ASFV) DNA grown in pig leukocytes (strain E70 L6) and after adaptation to growth in MS monkey kidney cells (strain E70MS14). The mapping data revealed that before adaptation to growth in MS cells, the size of the DNA from ASFV strain E70 L6 was l73 Kbp and after adaptation it was only l56 Kbp. The decrease in size was produced by deletions and additions mainly in the terminal regions of the genome. These genetic variations were located between 0.0 to 0.01 m.u. (Cla I-M1 fragment), 0.04 to 0.14 m.u. (Sma I-B1, Sal I-A1 fragments), 0.51 to 0.52 m.u. (Cla I-O fragment), 0.84 to 0.86 m.u. (Sma I-H1), 0.95 to 0.97 m.u. (Cla I-A1, Cla I-G1 fragments) and 0.99 to 1.0 m.u. (Cla I-G1) on viral genome of ASFV grown in pig leukocytes.
Subject(s)
African Swine Fever Virus/genetics , Chromosome Deletion , Genes, Viral , Iridoviridae/genetics , African Swine Fever Virus/growth & development , Animals , Cell Line , DNA Restriction Enzymes , DNA, Viral/genetics , Genetic Variation , Kidney/microbiology , Leukocytes/microbiologyABSTRACT
Sera from African swine fever-resistant pigs with infection-inhibitory activity decreased virus replication in infected porcine buffy coat cultures. This same effect was observed even after virus was adsorbed. The infection-inhibition was not reversed by removing the immune serum from the assay cultures. Reduction of African swine fever virus replication by immune sera was demonstrated by fluorescent focus assay on MS cell line cultures. Virus-neutralization tests showed a persistent fraction of non-neutralized virus, which was not demonstrable by infection-inhibition tests. One hypothesis for explaining this difference is proposed.
Subject(s)
African Swine Fever Virus/immunology , African Swine Fever/immunology , Immunity, Innate , Iridoviridae/immunology , African Swine Fever Virus/genetics , Amino Acids/metabolism , Animals , DNA Replication , Neutralization Tests , Swine , Viral Proteins/biosynthesis , Virus ReplicationABSTRACT
In assay cultures, sera from African swine fever convalescent pigs inhibited infection by homologous African swine fever virus. The infection-inhibition capacity did not correspond with the virus-neutralizing capacity. The serum did not prevent infection by heterologous virulent viruses. Sera from pigs challenge inoculated with the homologous virulent virus and later with a heterologous virulent virus inhibited the infection by different heterologous virulent viruses. These sera did not interfere with the infection by pseudorabies virus. The specificity of the reaction indicated that the infection inhibition was caused by antibody.
