Comparative study of poliovirus excretion after vaccination of infants with two oral polio vaccines prepared on Vero cells or on primary monkey kidney cells.

A comparative study was designed to assess the bioequivalence of 2 oral poliovaccines (OPV) produced on 2 different cell systems: primary monkey kidney (PMK) cells and the Vero cell line. The Vero cell line has been used to overcome the problem of obtaining a regular supply of high quality monkeys that are devoid of latent viruses. For this study, 9 children were vaccinated with PMK-OPV and 12 children with Vero-OPV. The comparison covered poliovirus excretion, reversion of polioviruses in the 5'-noncoding region, and immunogenicity. Major molecular markers in the 5'-noncoding region related to neurovirulence already had been identified at position 480 for type 1, position 481 for type 2, and position 472 for type 3 poliovirus. Two nucleic-acid based methods were designed for studying these positions: a RT-PCR followed by sequencing, which required preliminary culture and cloning; and a type-specific nested PCR followed by sequencing, which enabled direct detection and genotyping of polioviruses. Twenty-eight stool specimens were analyzed by this second method with no PCR inhibition problem. The use of Vero cell line did not modify the global pattern of poliovirus excretion, reversion frequency, or seroconversion. These results provide additional support for the use of the well-characterized Vero cell line in OPV manufacturing.

Safety and immunogenicity of Haemophilus type b-tetanus protein conjugate vaccine, mixed in the same syringe with diphtheria-tetanus-pertussis vaccine in young infants.

As new vaccines are developed there is increasing interest in reducing the number of injections given to children by combining vaccines in one syringe. We studied the safety and immunogenicity of Haemophilus influenzae type b-tetanus protein conjugate vaccine (PRP-T) administered at ages 2, 4 and 6 months mixed in the same syringe with DTP vaccine and its effects on the seroresponse to DTP vaccine. A group of 112 healthy 2-month-old infants received DTP-PRP-T or DTP-placebo mixed immediately before immunization in the same syringe. The addition of PRP-T to DTP did not increase the rate of local or systemic reactions. After the first, second and third dose, the PRP-T recipients showed a geometric anti-PRP antibody mean of 0.13, 2.31 and 6.40 micrograms/ml vs. 0.07, 0.05 and 0.05 micrograms/ml among the DTP-placebo recipients, respectively. Of the PRP-T recipients, 94 and 98% attained antibody concentration of greater than or equal to 0.15 micrograms/ml protein after the second and third dose, respectively, and 65 and 94% attained a concentration of greater than or equal to 1.0 micrograms/ml after the second and third dose, respectively. At the age of 1 year 94 and 52% of the DTP-PRP-T recipients vs. 12% and 0% of the placebo recipients still maintained titers of greater than or equal to 0.15 and greater than or equal to 1.0 micrograms/ml, respectively. The administration of DTP in the same syringe with PRP-T did not affect significantly the antibody response to diphtheria and tetanus toxoid and to pertussis agglutinins. It is concluded that PRP-T vaccine could be administered in the same syringe as DTP.

Qualification of working cell banks for the Vero cell line to produce licensed human vaccines.

Since 1980, Merieux Institute has prepared on microcarriers four working cell banks from Vero Cells (137th p.) received from the ATCC in May 1979 (at 124th p.). The lots have been or are used for the production of rabies and inactivated poliomyelitis vaccines. Three lots were controlled according to WHO requirements described in the technical report 673, 1982. For the fourth lot, we have followed the WHO requirements corresponding to the technical report 745, 1987. All the tests required us to demonstrate: i) Safety and purity (tests in animals and eggs, sterility tests, cocultures with human cells and other electron microscopic observations). ii) The absence of tumorigenicity (tests in newborn rats treated with antihymocyte serum at the WBC level and on the cells propagated to at least 10 population doublings beyond the maximum passage level used for production. Assays of cell transformation with DNA from the Vero line in the standard 3T3 assay system). iii) Identity (isoenzyme technique). All were satisfactory.

Intravenous immunoglobulins: can the blood pressure response in laboratory animals be considered a predictive criterion for good clinical tolerance?

Having noted that the only physico-chemical and biological test recommended cannot ensure good tolerance of i.v. IgG in man, we studied a physiological test consisting of evaluating blood pressure during infusion in conscious dogs (10 mg/kg/min) or after i.v. injection in rats (250 mg/kg in 12 sec.). The data were obtained on more than 100 dogs and 500 rats. For preparations known to be well tolerated in man or inducing a few clinical intolerances, the correlation with hypotension in rats and dogs seems good. Therefore, we think this test has its place in the battery of i.v. IgG qualification tests carried out before passage to man. Institut Mérieux has developed a new intact i.v. IgG equilibrated in sub-classes, without PKA, low in IgA and not hypotensive in these two species.

[Clinical forms of skin manifestations in allergy to perfume]. / Formes cliniques des manifestations cutanées d'allergie aux parfums.

Perfumes are increasingly used in an ever wider variety of fields, including perfumes proper, cosmetic products, hygienic products, drugs, detergents and other household products, plastics, industrial greases, oils and solvents, foods, etc. Their composition is usually complex; it involves numerous natural and synthetic sweet-smelling constituents, more than 5,000 of which are known (13). Perfumes may produce toxic and, more often, allergic respiratory disorders (asthma), as well as neurological (10) and cutaneous disorders. They are the most common cause of skin allergy to cosmetic products (1, 11) and one of the most important causes of skin allergy to topical drugs or even to syrups which may reactivate contact dermatitis (24). People engaged in the manufacturing of these products may become sensitized to perfumes.

Use of a combined DTP-polio vaccine in a reduced schedule.

A five-year serologic follow-up and a four-year monitoring of the polio and pertussis morbidity in an area immunized with a 2 + 1 dose schedule of a combined DTP-Po vaccine have shown that: the individual protection against polio measured by the presence of neutralizing antibody persists at a very adequate level five years after the first booster; after three years of a steady high proportion of children with pertussis antibody, a considerable drop is observed and in about 28% of individuals agglutinin levels of less than 1:20 were found five years after booster; the community protection against paralytic poliomyelitis and pertussis is satisfactory up to four years after the introduction of the program. Continuation of immunization with a 2 + 1 dose schedule at a maximal coverage and close seroepidemiologic surveillance are necessary in order to draw definite conclusions, because of the potentially strong impact of very dynamic ecological factors present in our geopolitical area upon the agent-host interrelationship.

A modified schedule for routine pertussis immunization.

As part of a study with a quadruple inactivated vaccine (diphtheria-pertussis-tetanus-polio), the serologic response to the pertussis antigen was investigated in infants at the age of routine immunization, inoculated with one of the following two regimens: either 0.5 ml vaccine at 2 and 3 1/2 months and a booster six months later, or an identical dose of vaccine given at 2, 4 and 6 months and a booster at the age of 12 months. A pertussis agglutination titer of greater than or equal to 1:10 was considered an immune response to the administration of the antigen. Two basic doses of pertussis antigen induced an immune response in about 92% of children, which was very close to that following three basic doses. A 100% seroconversion was observed in both groups one month after the booster dose, and geometric mean values were high in both regimens. At one and two years after the booster, the pertussis agglutinins were present in 100% of children of both groups, with higher geometric mean values in the group given the three basic doses regimen.

Pertussis immunization of infants using a new combined DTP-polio vaccine.

As part of the evaluation of a new combined Diphtheria-Tetanus-Pertussis-Poliomyelitis (DTP-Polio) inactivated vaccine, the pertussis agglutinin response was studied in 62 infants, two to three months old. Each dose of vaccine combined these antigens in a 0.5 ml volume, and contained at least four International Protective Units of pertussis antigen adsorbed on aluminium hydroxide. Infants were vaccinated with three doses of DTP-Polio vaccine at two month intervals. Pertussis agglutinin determinations showed a satisfactory response after two DTP-Polio vaccine doses. Although higher agglutinin titres were apparent after three doses than after two, no significant difference was observed in the seroconversion rate after two or three doses (88.8% and 96.3% respectively). The DTP-Polio vaccine would thus seem suitable for use in a two-dose primary immunization schedule against pertussis.

Comparison of sensitivity of VERO cell line versus primary monkey kidney cells in the detection of residual live polio virus during and after inactivation.

Substitution of Primary Monkey Kidney (PMK) Cells by Monkey Cell Lines (MCL) for detection of residual live virus in poliovaccine control has been considered for various reasons. The sensitivity of VERO Cells versus PMK cells has been investigated. This study was done with poliovirus during and just after formalin inactivation. The amount of residual live virus was tested by TCID50 end-point titrations in roller-tubes and small bottles at different stages in the inactivation process. Just before or at the end of inactivation, a 1 000 doses vaccine equivalent volume was tested on Roux bottles. Thus far the results show that VERO cells seem to be less sensitive than PMK cells, especially for type 3 virus. Additional studies will be needed to investigate whether the sensitivity of the VERO cells can be improved to detect residual live poliovirus during and after inactivation with the same sensitivity as PMK cells.

Production of inactivated rabies vaccine for human use on WI38 diploid cells. Results of potency tests. Stability of the vaccine in liquid and freeze-dried forms.

The purpose of the article is to give the experience gained with the manufacture of the vaccine for five years and to dicuss the potency results obtained. Sixty ampoules of WI38 cells were used. The processing of twelve of them was stopped for accidental reasons. Forty-eight lots were freeze-dried, four were rejected as final product, three lots because of low potency, one following some febrile reactions in children due to an unexpectedly high content in endotoxin. The activity level of each lot was determined: (1) by titration of the viral suspension before concentration in young mice by the intracerebral route or by the plaquing technique in monolayers of BHK 21 cells. The mean titer in mice is 10(6.5) per ml; on cells the titer is lower, mean 10(5.8) per ml, but more homogeneous, and (2) by the NIH potency test in mice: 90% of the lots have an antigenic value compared to the International Reference Vaccine above 2. There is not a good agreement between the results of the NIH potency test and the titer of the viral suspension. The antigenic values obtained on the freeze-dried vaccine after storage one month at 37 degrees C are the same as those for the vaccine stored at + 4 degrees C. The activity is not modified after storage for two years at + 4 degrees C in the freeze-dried or in the liquid state. The main drawback of the vaccine is its high cost. Some suggestions are proposed to try to lower it and to find a sound compromise between high quality and price.