ABSTRACT
This study addresses observations made in view of testing in practice the guideline in the European Pharmacopoeia (EP) on omitting the rat potency test for release of polio containing vaccines. In general, use of the guideline is valid and the D-antigen ELISA can indeed be used as an in vitro alternative for the in vivo test. However, the set-up of the ELISA is crucial and should include detection of antigenic site 1 in polio serotype 3 as destruction of that site by trypsin results in a reduced rat potency. Antigenic site 1 in polio serotype 2 may also be modified by trypsin, but the cleavage of viral protein 1 (VP1) did not affect the rat potency. Therefore, any antigenic site, except site 1, can be used for detection of polio serotype 2. It is advised to include testing of the effect of trypsin treatment in the EP-guideline. This allows polio vaccine manufacturers to check whether their in-house ELISA needs improvement.
Subject(s)
Biological Assay , Enzyme-Linked Immunosorbent Assay , Poliovirus Vaccine, Inactivated/immunology , Poliovirus/drug effects , Trypsin/pharmacology , Animals , Antibodies, Neutralizing/biosynthesis , Antibodies, Viral/biosynthesis , Biosensing Techniques , Capsid Proteins/drug effects , Chlorocebus aethiops , Dose-Response Relationship, Immunologic , Europe , Hot Temperature , Poliovirus/immunology , Poliovirus/isolation & purification , Poliovirus/pathogenicity , Practice Guidelines as Topic , Rats , Vero Cells , Virulence/drug effectsABSTRACT
In order to achieve batch-to-batch consistency of whole-cell pertussis vaccines, properties relevant for protection and safety should be characterised. Therefore, ELISAs to quantify pertussis toxin (PT), filamentous haemagglutinin (FHA), 92 kD outer membrane protein (92 kD-OMP) and pertactin (PRN) in Bordetella pertussis (B. pertussis) suspensions were developed. In this paper the influence of the bacterial growth stage on antigen production and antigen release into the supernatant was studied for pertussis strains 134, 509 and CS. The levels of cell-associated and free antigens during growth were strongly strain and antigen dependent. Because of this, the proportion of cell-associated antigens changed during cultivation for all three strains. Substantial amounts of PT and PRN were released into the supernatant, while little free FHA and 92 kD-OMP were found. The amount of cell-associated FHA declined rapidly during growth, whereas cell-associated 92 kD-OMP contents increased. These findings demonstrate that, although antigen exposure and release differ from strain to strain, the main factor that determines the antigen production and release is the growth phase.
Subject(s)
Antigens, Bacterial/analysis , Antigens, Bacterial/metabolism , Bordetella pertussis/immunology , Bordetella pertussis/metabolism , Enzyme-Linked Immunosorbent Assay/methods , Pertussis Vaccine/chemistry , Virulence Factors, Bordetella , Adhesins, Bacterial/immunology , Antigens, Bacterial/biosynthesis , Bacterial Outer Membrane Proteins/immunology , Bacteriological Techniques , Bordetella pertussis/growth & development , Culture Media/metabolism , Hemagglutinins/immunology , Pertussis Vaccine/immunology , Pertussis Vaccine/metabolism , Protein Binding/immunology , Reproducibility of ResultsSubject(s)
Antigens, Bacterial/analysis , Bordetella pertussis/growth & development , Adhesins, Bacterial/analysis , Antibodies, Monoclonal , Bacterial Outer Membrane Proteins/analysis , Bordetella pertussis/immunology , Enzyme-Linked Immunosorbent Assay/methods , Flow Cytometry/methods , Hemagglutinins/analysis , Virulence Factors, Bordetella/analysisABSTRACT
A general multi-tasking control system has been developed for real-time signal processing. This control system, written in the language PASCAL, enables tasks (expressed as PASCAL procedures) to be performed as separate, concurrent processes, with adjustable priority levels. Modifications of this system such as the addition of new processes and a change of the number of priority levels can be realised easily. The system has been used for the implementation of the real-time algorithms involved in monitoring exercise electrocardiograms. For this application an LSI 11/23 is used with the support of a slave processor for the calculation of inner products. The control system is also suitable for other real-time applications when process requirements are not too heavy.
