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B Lomniczi

Publications and source records attributed to B Lomniczi.

58 records · Page 4Linked to original sources
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Rapid identification of Newcastle disease virus vaccine strains LaSota and B-1 by restriction site analysis of their matrix gene.

A region constituting 88% of the matrix gene of Newcastle disease virus vaccine strains LaSota and B-1 was amplified by reverse transcription-polymerase chain reaction. Amplified products of LaSota and B-1 strains derived from vaccine serials of different companies were digested with restriction enzymes MboI and HinfI. Strain characteristic cleavage site maps were obtained that allowed for a reliable and rapid differentiation between strains LaSota and B-1.

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PubMedDate not supplied

Properties of non-neurovirulent plaque-forming mutants of Newcaslte disease virus.

The mesogenic Hertfordshire (H) strain, a vaccine strain of Newcastle disease virus, represents a heterogeneous virus population differing in physical, chemical, and biological properties. Small (S) and large (L) plaque-forming mutants were isolted from strain H in chick embryo fibroblast cell cultures. Part of the S mutants lacked neurovirulence, with an intracerebral pathogenicity index for day-old chicks of 0 to 0.46 vs 1.0 to 1.4 for L mutants. S mutants grew only to a very low titer in the brain of day-old chicks and cleared from the brain by the sixth day, whereas L mutants killed the chicks after a 1000-fold titer rise. The S mutants caused a complete cell destruction in fibroblast culture by 12 hours, but they had 10--20 times lower virus yields than the L mutants. The infective titers of S and L mutants grown in allantoic cells were identical, but the infectivity to hemagglutinin ratio was 10 to 50 times lower for S than for L. The thermostability of infectivity and hemagglutinin varied with the different mutants. As for the immunogenicity of the mutants, the minimum dose of S mutants inducing full protection by subcutaneous inoculation was 10(6) plaque-forming units per chicken, thus being about 100 times less immunogenic than either the L mutants or the parent strain H.

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