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Query: UMLS:C0149514 (bronchitis)
 6,902 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Long-term organ cultures of a range of tissues collected from specific pathogen-free chickens were employed to determine their susceptibility, and their capacity for subsequent virus production, following inoculation with avian infectious bronchitis (AIB) virus. When inoculated with approximately 2-0 log10 median ciliostatic doses (CD50) of a classical highly egg-adapted vaccine strain (H120) of AIB virus, 9 of 23 tissues were shown to be susceptible, namely the nasal turbinates, trachea, air sac membranes,lungsasal turbinates, trachea, air sac membranes, lungs, proventriculus mucosa, thyroid, kidney, ovary and oviduct. When the remaining 14 tissues were inoculated with a high dose of virus (6.8 log10 CD50), the conjunctiva, caecel tonsil, testis and bursa of Fabricius were susceptible whereas the oesophagus and cloaca responded minimally. Inoculation of the same range of tissues with a high or low dose of a field strain (HVI9) of AIB virus produced similar results, except for a number of individual variations in response, due possibly to strain differences in pathogenicity. Determinations of the minimal infectious dose requirements of the susceptible tissues revealed that the efficiency of infection with the H120 strain was highest for the nasal turbinate and tracheal tissues, and thereafter, in order of decreasing efficiency, were the air sac membranes, lung, oviduct, proventriculus mucosa, conjunctiva, kidney, ovary, bursa of Fabricius, thyroid, testis, caecal tonsil, cloaca and oesophagus. The relevance of these results is discussed in connection with the early events in the pathogenesis and the clinical syndrome of AIB infection in chickens.
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PMID:Organ culture studies on the efficiency of infection of chicken tissues with avian infectious bronchitis virus. 18 5

The antigenic relationships of 24 strains of avian infectious bronchitis virus (IBV) were investigated by serum neutralisation tests performed in chick embryo tracheal organ cultures. The serum dilution that neutralised 100 median ciliostatic doses (CD50) of virus was estimated from the linear relationship between varying concentrations of each virus strain and the neutralisation titre of homologous antiserum; this dilution defined 1 antibody unit. Antisera diluted to contain 20 antibody units were then tested by neutralisation against 1.5--2.5 log10 CD50 of each strain. Clusters of both strains and antisera in turn were established by methods of numerical taxonomy using as measures of resemblance Euclidean distance and correlation coefficient, and by analysis by principal components. These analyses identified a group of 8 similar strains; neutralisation of the remaining 16 strains was slight. Similar results were obtained by classifying antisera, except that a further group of 3 antisera was demonstrated, each having a neutralising capacity for most strains. Implications for vaccine formulation are discussed.
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PMID:Taxonomic studies on strains of avian infectious bronchitis virus using neutralisation tests in tracheal organ cultures. 22 44

Six commercial infectious bronchitis virus (IBV) vaccines and five IBV field strains were titrated in tracheal organ cultures (TOC) and oviduct organ cultures (OOC). Endpoints were determined in three different ways: ciliostasis (CD50), immunofluorescence staining (IFID50) and organ culture infectivity (OCID50). For the two most attenuated vaccine viruses, infectivity assessed by IFID50 and OCID50 was significantly higher than that assessed by CD50. No significant differences were found between IFID50 and CD50 with the five virulent viruses in either OOC or TOC. This suggests that the most attenuated viruses multiply in these tissues to a greater extent than assessed by their pathogenic potential i.e. ciliostasis. Comparison of IFID50 and CD50 may be a useful method for screening candidate live respiratory viral vaccines for attenuation. OOC prepared from oestrogen-treated embryos were not efficacious.
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PMID:Growth of infectious bronchitis virus vaccines in oviducts derived from oestrogen-treated chicks and embryos. 906 33

A sandwich ELISA (sELISA) employing four monoclonal antibodies as capture and IgG from egg yolk of hyperimmune hens as detecting antibodies was developed for the simultaneous detection and differentiation of infectious bronchitis virus (IBV) antigen in both allantoic fluid and tissues from experimental and field infections. Between 10(2) and 10(3) median ciliostatic dose (CD50) of virus was required for the detection of the majority of IBV strains in allantoic fluid. In chicks infected with 10(4 )to 10(6) CD50 of virus there was a good agreement between sEOSA and virus isolation. EBV antigen was detected in trachea of chicks having virus titres of 10(2 )CD(50). Following vaccination with the recommended dose of two IB vaccines, IBV antigen was not detected by sELISA. There was also a good correlation between sELISA and virus isolation on samples obtained from field infections. In two broiler flocks with respiratory disease, IBV antigen was detected by sELISA in a high proportion of samples. In one flock, two antigenically different strains were detected, one of which was vaccine virus. The other IBV strain identified was a new antigenic variant not previously detected.
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PMID:Detection and differentiation of avian infectious bronchitis viruses using a monoclonal antibody-based. 1864 94