Quantitative determination of the human immune response to immunization with meningococcal vaccines.

Radioactive antigen binding tests have been developed to measure quantitatively the antibody response of 167 adults, 84 children, and 51 infants to several different preparations of group A and group C meningococcal polysaccharides. Almost all the adults injected responded and the geometric mean responses were approximately 15 mug/ml of antibody protein in individuals vaccinated subcutaneously with two preparations of group A vaccine. The geometric mean antibody concentration after immunization with two preparations of group C vaccine was approximately 35 mug/ml. Most children aged 7 yr responded to immunization with two group A vaccines, and their mean response was only slightly less than that seen in adults. There was no difference between the subcutaneous and the intradermal route if both were given with jet gun. The majority of infants aged 6-13 months responded to a preparation of group A vaccine and the geometric mean titer was approximately 1.2 mug/ml. Adults, children, and infants responded significantly less to a preparation of group A polysaccharide which was of low molceular weight.

[20 years' use of the diphtheria-pertussis-tetanus vaccine]. / Vingt années d'utilisation du vaccin diphtérique-tétanique-coquelucheux (DTcoq).

Between 1966 and 1982, a triple DPT vaccine was studied in France in 1,871 infants between the ages of 3 and 5 months. The study covered tolerance and serological efficacy of two immunization schedules using 2 or 3 initial injections. Computerized analysis of the 877 complete files showed satisfactory tolerance of this association and the serological efficacy of 2 initial doses of tetanus and diphtheria vaccines. Pertussis immunization is only effective after 3 injections. The presence of maternal antibodies when the first injection is given only decreases the immune response of diphtheria vaccine.

Intradermal immunization with rabies vaccine. Inactivated Wistar strain cultivated in human diploid cells.

We report a comparative study of the Mérieux Institute's inactivated rabies vaccine administered intradermally or subcutaneously. Vaccine safety was satisfactory, with only minor local and generalized reactions. Serological effectiveness was outstanding: all of those who had been seronegative became seropositive following either two intradermal or subcutaneous injections given one month apart. A comparison of the intradermal and subcutaneous routes demonstrated several important points. Antibody titers developing after subcutaneous immunization were greater than after intradermal immunization. The kinetics of antibody development during primary immunization were parallel in the two immunization protocols. Eleven months after primary immunization, subcutaneous administration of a booster dose of vaccine resulted in a titer elevation 1.86-fold greater than that in intradermal administration. Each of these levels indicated good serological response.

[Serological evaluation of an antimeningococcal mass vaccination campaign in Niger]. / Evaluation sérologique d'une campagne de vaccination antiméningococcique de masse au Niger.

Authors searched by mean of radio-immuno-essay A and C anti-meningococcal antibodies in two villages from Niger (181 and 92 patients) in a meningitidis endemic area, which one profited 10 months ago of a mass vaccination campaign (A and C polysaccharides). A and C antibodies quantities and percentages of protected patients are not significantly different between the two villages. In one hand anti-C levels increase with patients age. In the other hand, there is a correlation between C meningococcal antibodies and anti-Hbc antibodies.

Antibodies to meningococcus polysaccharides in nonspecific gamma-globulins from different regions of the world.

Seventy-one batches of nonspecific gamma-globulin obtained from France, USSR and Mongolia were studied for presence of specific antibody to group A and C meningococcus polysaccharide. Specific activity was tested by two methods: radioimmunoassay (Lyon) and reaction of passive haemagglutination inhibition (Moscow). Antibodies were detected in all the gamma-globulin batches tested, in some of them at high titres. The summary results indicated that approximately equal levels of specific A antibodies were present in preparations obtained from the different regions of the world. Antibodies to group C polysaccharide showed considerable variation in level from selection country to country; the highest level of C antibodies was in gamma-globulin from France. The authors feel entitled by the results to recommend testing of nonspecific gamma-globulin, selection of batches with a high level of specific antimeningococcus antibodies, and their judicious use.

[Results of preventive rabies vaccination with a concentrated vaccine of the PM/WI38-1503-3M rabies strain cultured on human diploid cells. Preparation of mixed antirabies-antitetanus hyperimmune immunoglobulin by plasmapheresis of blood taken from vaccinated veterinary students]. / Résultats de la vaccination antirabique préventive par le vaccin inactive concentré souche rabies PM/WI38-1503-3M cultivée sur cellules diploïdes humaines. Obtention d'immunoglobuline hyperimmune mixte antirabique et antitétanique par plasmaphérèse des étudiants vétérinaires vaccinés.

Many thousands of people in France and abroad have already benefited from preventive rabies vaccination by means of a vaccine obtained from culture on human diploid cells, perfected ten years ago by R. Lang, the Institut Mérieux and the Wistar Institute. In addition to being well tolerated, the serological efficacy of this vaccine is such that 100% of the vaccines observed had a seroconversion after only two injections at an interval of one month. However, a booster dose should be given 6 to 12 months after the first injection, and a further booster 3 to 5 years later or on request in case of known contamination. These boosters, combined with an anti-tetanus booster, induce such high antibody titers--between 10-100 and even 1000 I.U./ml--that it is easy to obtain substantial batches of combined anti-rabies and anti-tetanus immunoglobulin from a small number of volunteers. The complete efficacy of this new vaccine reduces the number of systematic post-vaccinal serologic controls and its innocuity is such that an extended preventive vaccination programme may be carried out, for instance in the case of children living in areas known to be dangerous.

Combination of attenuated measles vaccine (Schwarz) with meningococcus A and A + C vaccine.

There is an obvious interest in a combined meningococcus-measles vaccine since the two diseases are widespread and serious in Third World countries among children under five years of age. The purpose of our study was to show the safety and effectiveness of such a combined preparation. The study covered 110 children between 8 months and 4 years of age who were followed systematically in a maternal child health center in the Paris area. Only 93 of them were checked before and after the immunization. The serologic titrations by the hemagglutination assay (IHA) for measles, and by radioimmunological assay (RIA) for meningococcus A and C showed that the Schwarz strain measles vaccine combined with meningococcus A or the association A+C does not interfere with the increase of A or C titers. 100% of the children showed a seroconversion equal to or less than 2 micrograms per ml, in the case of meningococcus A, as well as for C, regardless of age. Furthermore, 88% of the subjects showed a titer greater than or equal to 4 micrograms for the meningococcus A and 79% for C. On the other hand, meningococcus A or the association A+C seem to depress measles vaccine activity. Nevertheless, more than 80% of the children tested showed seroconversion when the measles vaccine was combined with meningococcus A, and only 69% when combined with meningococcus A and C.

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.

A controlled field trial of a serogroup A meningococcal polysaccharide vaccine.

A controlled field trial of a serogroup A meningococcal polysaccharide vaccine was conducted at three locations in Egypt during the winter cerebrospinal meningitis (CSM) season of 1971-72. The study population consisted of schoolchildren 6-15 years of age. No cases of serogroup A meningococcal CSM occurred in the group of students vaccinated with the test vaccine whereas 8 cases occurred in the control group vaccinated with tetanus toxoid, and 151 cases occurred in an unvaccinated contrast group. The case rate was significantly different between the test and control groups as well as between the test and contrast groups but was similar between the control and contrast groups. The previously demonstrated safety of the vaccine was confirmed. A significant serological response was elicited in the majority of the vaccinated students.