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Biomedical subjects

A L van Wezel

Publications and source records attributed to A L van Wezel.

54 records · Page 3Linked to original sources
PubMed1979

Intratypic serodifferentiation of poliomyelitis virus strains by strain-specific antisera.

Strain-specific antisera against non-Sabin-like and Sabin-like poliovirus strains were prepared by cross-absorption of the antisera with the heterologous strain. Isolates from different parts of the world were differentiated intratypically as non-Sabin-like and Sabin-like strains with the aid of these sera in the immunodiffusion test and neutralization test. In comparison with other marker tests, intratypic differentiation can be performed more easily. Further, fewer intermediate strains were found and, in our opinion, the results are more reliable.

Humans↗
PubMed1979

Large-scale concentration and purification of virus suspension from microcarrier culture for the preparation of inactivated virus vaccines.

Because of the presence of bovine serum proteins in poliovirus and rabiesvirus suspensions harvested from microcarrier cultures, a concentration and purification process has been developed in order to remove these proteins. The process comprises clarification by filtration, concentration by ultrafiltration, gel filtration on Sepharose 6B and column chromatography on DEAE-Sephadex A50. The serum protein content of the virus suspensions if reduced to a serum dilution of less than 1: 10(6) at a virus antigen recovery rate of 70 to 80%.

Animals↗
PubMed1979

Isolation of biologically active components from rabies and other envelope viruses.

Most human virus vaccines contain complete virus particles, either inactivated or attenuated. Besides components responsible for induction of neutralizing antibodies, other virus components (e.g. nucleic acids, lipids) are also administered upon vaccination. For envelope viruses the (glyco) proteins of the viral envelope are generally involved in the induction of neutralizing antibodies. Our investigations are focussed on the large scale preparation of these components from several viruses or virus vaccines, such as rabies and influenza. For virus disintegration we have tested several ionic anc nonionic detergents. Triton X-100 gave good results. Separation of solubilized components from the remainder of the virus has been carried out on a small scale by ultracentrifugation. For the purification of influenza hemagglutinin and neuraminidase we also used gelfiltration with success. The latter process can be scaled up easily. The main problem in the process of virus subunit preparation is the removal of detergent.

Hemagglutinins, Viral↗
PubMed1978

New approach to the production of concentrated and purified inactivated polio and rabies tissue culture vaccines.

The preparation of inactivated polio and rabies vaccine in tissue culture has been developed into a "Unit Process" at our laboratory during recent years. The process comprises trypsinization of animal kidney cells by the perfusion method, cell/virus cultivation in microcarrier culture and concentration and purification of the virus suspension followed by inactivation. Also, the control tests on the virus suspensions and vaccines are performed, to the greatest possible extent, according to the same procedures. In the meantime, both vaccines thus prepared have been tested in man. High antibody titres have been obtained and no adverse reactions have been observed. The results of a field trial with inactivated poliovaccine, administered at different concentrations, will be presented by Dr Salk. Preliminary concepts for further development of the production and control of these inactivated virus vaccines are discussed.

Antibodies, Viral↗
PubMed1978

Killed poliovirus antigen titration in humans.

To establish the antigen content of a killed poliovirus vaccine sufficiently potent to induce immunity with one or two doses and to establish a reference standard vaccine which has been tested under field conditions, a titration was carried out in infants to determine the amount of each of the three antigenic types of poliovirus vaccine required to induce seroconversion with a single dose. It has been observed that over a critical range of antigen concentration there is an essentially linear relationship between antibody response and quantity of antigen administered. More than 90 percent of the groups studied had detectable antibody after receiving single injections of 80, 8 and 64 D-antigen units of Types I, II and III, respectively. Four-fold less antigen for each of the three types was less effective. The implications of these findings for an efficient immunization procedure are discussed.

Antibodies, Viral↗
PubMed1978

Production of an inactivated rabies vaccine in primary dog kidney cells.

In this paper the large-scale production of a purified inactivated rabies vaccine in primary dog kidney cells cultivated in microcarrier culture is described. The potency in the NIH-test and the antigenicity of this vaccine in other animal experiments were comparable with the antigenicity of vaccine prepared in human diploid cells. The antibody response was greatly enhanced by the addition of AIPO4 as adjuvant. The results of an initial clinical trial are presented.

Animals↗
PubMedDate not supplied

Inactivated poliovirus vaccine: current production methods and new developments.

The biotechnologic developments during the last decade have led to the production of inactivated poliovirus vaccine (IPV) on an industrial scale and at economically acceptable costs. Replacement of primary monkey kidney cells by subcultured monkey kidney, Vero, or human diploid cells as substrate for virus multiplication as well as the introduction of the microcarrier culture technique have made cell and virus cultivation in large fermentors of 100-1,000 liters feasible. Procedures for processing virus harvests into highly concentrated purified vaccines were developed; also, the safety and potency control tests were improved and simplified. It has been demonstrated that these more potent poliovirus vaccines, either alone or in combination with diphtheria-tetanus-pertussis vaccine, induce a high immunity with reduced vaccination schedules. The overall costs of vaccination will be reduced considerably in this way. In addition, the results of biochemical and immunologic studies indicate that neutralizing antibodies can be induced by the viral proteins alone. These findings open up promising perspectives for production of subunit poliovirus vaccines with use of recombinant DNA and synthetic antigen, a method that has already proved feasible for producing vaccine against foot and mouth disease. These new techniques may lead to a further reduction of production costs and will improve the safety of the vaccine.

Animals↗
PubMedDate not supplied

Different secretory IgA antibody responses after immunization with inactivated and live poliovirus vaccines.

The influence on secretory IgA antibody levels in milk and saliva of vaccination with oral, live poliovirus vaccine ( OPV ) and inactivated poliovirus vaccine (IPV) was studied. IPV, especially the antigen-rich Dutch vaccine, more often induced increases in antibody titers in milk (50%) than did OPV (26%) (P less than .01). OPV more often decreased the antibody levels in milk (40%) than did IPV (10%) (P less than .01). It was striking that mainly high prevaccination titers were decreased. The increases of IgA antibody in saliva were less striking. IPV caused increases as often in milk as in saliva, whereas OPV more often induced increases in IgA antibody in saliva, but there was a poor correlation between the changes in antibody titers in milk and those in saliva.

Antibodies, Viral↗
PubMedDate not supplied

Standardization of poliovirus neutralizing antibody tests.

Recently the Forum for Advancement of Immunization Research sponsored a Collaborative Study on Poliovirus Antibody Titration. Twenty laboratories from 12 countries participated. There were considerable differences in detail of test performance and test results among laboratories. The sensitivity of the tests varied over a 10-fold range (geometric mean titer from 21 to 288). The average coefficient of variation ranged from 4.5% to 13.5%. Tests performed at the Food and Drug Administration indicated that Hep-2 cells were more suitable than Vero cells for poliovirus titration by cytopathic effect end point or plaque assay. However, the cell lines were equally suitable for polio antibody titration by neutralization of cytopathic effect. A high degree of sensitivity and optimal reproducibility of antibody assay were observed in tests utilizing a medium to low dose of virus and serum-virus incubation overnight at 36 C. On the basis of current experience, a protocol is proposed for a test that provides high sensitivity and reproducibility and is practical for large-scale determinations of poliovirus antibody.

Animals↗
PubMedDate not supplied

The large-scale cultivation of diploid cell strains in microcarrier culture. Improvement of microcarriers.

The use of diploid cell strains for virus vaccine production is mostly retarded by the inefficient culture techniques used for the propagation of these cells. The microcarrier culture system might be a good solution for this problem. DEAE-gels appear to be the most satisfactory microcarrier. The best results are obtained by using DEAE-gels with a rather low anionic exchange capacity or at higher capacity after coating with polymers.

Anion Exchange Resins↗