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Biomedical subjects

M Thibon

Publications and source records attributed to M Thibon.

30 records · Page 2Linked to original sources
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Antibody response to anti-A/New Jersey/76 vaccines.

Experimental inactivated influenza vaccines prepared with strain X 53, derived from A/New Jersey/76 virus were injected to several groups of subjects. Different compositions of vaccine were used and the subjects were selected from different age groups. Antibody responses were measured 15 days after vaccination; it was then possible to evaluate the conversion rates, the percentages of subjects showing a protective level of antibodies and the average level of antibodies. The results show that a very small dose of antigen, probably acting as a booster, gives very good results in the older age group. On the other hand, young adults (below 23) react to a much lower degree to the vaccine. The results are discussed in relation to the age distribution of preexisting antibodies in the experimental groups and in the general population in France.

Adult↗
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Effects of vaccination on an influenza epidemic in a geriatric hospital.

During winter 75/76 (from February 1 to March 31) we got the opportunity to follow the incidence of an influenza epidemic that occurred in the geriatric hospital of Ivry. Its population was, on the average, 83 years old. 958 persons were involved in this study: 523 out of them had been vaccinated with Pasteur bivalent Mutagrip A + B vaccine. The epidemic had a double origin: it was due to a virus A/Victoria and to a virus B/Hong Kong. A significant difference was noted between the vaccinated group and the nonvaccinated one. Serological (CF and HI) and virological investigations (virus isolation) were performed on 110 subjects. The clinical course followed by the disease was mild for the vaccinated and severe for the nonvaccinated. Mortality rate was 0.19% in the former against 3.90% in the latter. It has been thus possible to observe an "immunological fence" since it appears that when 79% of a given unit has been vaccinated, influenza incidence has been as much as three times reduced.

Aged↗
PubMedDate not supplied

Ability to activate the alternative complement pathway acquired by human and guinea-pig erythrocytes after contact with influenza virus.

Human sera exhibited a little haemolytic activity on native guinea-pig erythrocytes, but became potently cytolytic for guinea-pig erythrocytes previously incubated with influenza virus. These haemolytic activities were relevant to complement activation since chelation of Ca++ and Mg++ by EDTA prevented the haemolysis as did also previous heating of sera to 56% C. The haemolysis of native red cells was promoted by human natural antibodies against guinea-pig cellular antigens, which activated the direct pathway of complement. On the other hand, haemolysis of influenza-treated cells was produced by an activation of the alternative pathway since haemolysis occurred in conditions where the direct but not the alternative pathway was blocked. Human antibodies, however, may enhance the alternative pathway but did not trigger it. The same haemolytic phenomena was observed after removal from guinea-pig erythrocyte membrane of sialic acid residues by neuraminidase. While complement-mediated haemolysis never occurred in a homologous system, that is with virus-treated cells and sera from the same species, we noticed in that case a strong haemagglutination. This observation suggested that a species recognition prevented complement mediated haemolysis, but supported the hypothesis of a complement regulation by endogenous protein(s), the complement sequence being blocked before the apparition of the cytolytic activity. The possibility of a role for the complement in the non-specific defence against the infection and a participation to the inflammatory process through this mechanism is also discussed.

Adsorption↗