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Biomedical subjects

D A Tyrrell

Publications and source records attributed to D A Tyrrell.

At least 271 records · Page 15Linked to original sources
PubMed1969

Antibody responses to and efficacy of an inactivated spray vaccine.

An attempt was made to assess the protective influence of killed intranasal influenza B vaccine against a homologous virus challenge. Two types of trial were performed. In the first of these, the vaccine was compared with an inert placebo and, in the second, with conventional homologous and heterologous parenteral vaccines. Little protective effect by the intranasal vaccine was demonstrated.

Adult↗
PubMed1969

Some studies on the selection and efficiency of live influenza vaccine viruses.

Live influenza virus vaccination has potential advantages and disadvantages compared with killed virus vaccine given by intramuscular injection.Attempts have been made to achieve complete attenuation of influenza A2 and B strains by up to 30 serial passages in the allantoic cavity of eggs at 33 degrees C. No attenuation occurred. The method of passing viruses in the presence of an increasing concentration of horse serum, thus selecting inhibitor-resistant variants, has also been tested. It was shown that serial passage induced an increasing degree of inhibitor resistance in the virus and an increasing degree of attenuation when tested in volunteers. This was observed with both an Asian strain and a Hong Kong strain. The Hong Kong virus was also passed serially at 25 degrees C in eggs but did not seem much further attenuated as a result; however, a virus strain supplied by H. F. Maassab with a much higher degree of adaptation to low temperature is being tested.Partly or completely attenuated strains have been used to induce or detect protection. Influenza B strains gave partial protection after 1 dose and almost complete protection after 2 doses and protection persisted for 7 months. A comparative study showed that there was protection after vaccination with killed virus by the parenteral route, and with live virus by the nasal route.

Genetic Variation↗
PubMed1968

Investigetion into the attenuation of influenza viruses by serial passage.

For vaccination live viruses are better than dead ones, but live influenza vaccines are difficult to prepare. One influenza A(2) and two influenza B viruses were passed in series in embryonated eggs. At several stages of their passage they were inoculated into volunteers, and their effects assessed by virus isolations, antibody rises, and clinical reactions. The A(2) virus and one of the influenza B viruses, both of which had grown readily in embryonated eggs on first isolation, continued to induce human infections and clinical reactions after 30 egg passes. The other influenza B virus acquired enhanced human pathogenicity after three passages from man to man. After adaptation to eggs in which it at first grew reluctantly, its human virulence was appreciably reduced. It underwent no further change during a total of 20 egg passes. There was little convincing evidence of an increased incidence of clinical reactions during the winter seasons, but the numbers of volunteers were too small to draw definite conclusions.

Animals↗
PubMed1968

Production of common colds in human volunteers by influenza C virus.

Influenza C virus was intranasally administered to volunteers; most were infected and nine developed symptoms of common cold.Increasing titres of serum haemagglutination-inhibiting antibody and complement-fixing antibody were detected. Virus neutralizing activity in nasal secretion was not correlated with either resistance to infection or the occurrence of overt illness. Interferon was detected in the nasal secretions of some subjects.

Antibodies↗