The authors describe some recent investigations undertaken in Japan with the object of finding an adjuvant for dried BCG vaccine which would make it possible for the vaccine to be stored at room temperature in tropical countries without suffering any serious loss of viability.The first series of experiments, carried out with sodium glutamate as adjuvant, was designed to determine the effect of the concentration of adjuvant, the concentration of bacilli, the pH of the bacterial suspension, and the method of freeze-drying on the preservability of the vaccine. The sucrose vaccine in current use in Japan served as a control. In the light of the results, the authors make certain suggestions as to the optimum conditions for freeze-drying, but they stress that their proposals are tentative and that further research on the subject is needed.In the second series of experiments the authors investigated the adjuvant properties of certain organic acids known to be involved in the metabolic reactions of the tubercle bacillus. Reasonably good results were obtained with alpha-ketoglutaric, malic, lactic, and citric acids, but none of these substances proved to be as satisfactory an adjuvant as sodium glutamate for storage at 37 degrees C.

BCG Vaccine↗

PubMed1957

Effect of storage at 37 degrees C on allergenic potency of dried BCG vaccine.

Experiments were carried out to determine the effect of storage at 37 degrees C on the allergenic potency for humans of dried BCG vaccine. From four lots of liquid vaccine, eight kinds of dried vaccine were prepared, four with 1% sodium glutamate and four with 1% sucrose as adjuvant. The eight vaccines were stored at 5 degrees C and at 37 degrees C for periods ranging from 1 month to 9 months, and were then used for the inoculation of primary-school children in Tokyo. These children were tuberculin-tested 1, 3 or 4 and, in a few cases, 12 months after vaccination, and the reactions were read approximately 48 hours after the tuberculin injection had been given.The tuberculin reactions induced by inoculation of the glutamate vaccines stored at 37 degrees C were, in all cases, appreciably stronger than those induced by the sucrose vaccines after storage at the same temperature for the same period. A slight decrease in the potency of the glutamate vaccines was observed after storage for 3 months at 37 degrees C, but storage for 1 month at this temperature did not appear to have any adverse effect on the potency.

Allergens↗

PubMed1957

Further studies on BCG vaccine prepared by tween 80 method with particular reference to effect of freeze-drying.

The immunizing potency of liquid BCG vaccine prepared by the Tween 80 method was compared with that of control vaccine prepared by the usual grinding method. The former vaccine revealed higher immunizing properties than the latter although its inoculation dose was only one-fifth as great.With sodium glutamate as adjuvant, freeze-drying was carried out on both vaccines. The viability of the resulting dried product was higher with the Tween 80 vaccine than with the control vaccine up to 12 months' preservation at 5 degrees C, and the allergenic potency of the dried Tween 80 vaccine stored at 5 degrees C was higher than that of the control vaccine. When the dried vaccine was preserved at 37 degrees C for a long period, the degree of decrease in viability was more marked in the Tween 80 vaccine than in the control vaccine.

BCG Vaccine↗

PubMed1956

Effect of preservation on the viability and allergenic potency of dried BCG vaccine.

Although many studies have been made on the lyophilization of BCG vaccine, few reports on its stability have appeared. The amount of living bacilli present in the vaccine and its allergenic potency can be considered to be an indication of the stability of the vaccine. The authors have already reported on the change in viability of vaccines preserved for 17 months; in this paper two experiments on lots of vaccines preserved for three years are discussed. The authors determined changes in viability after storage and examined tuberculin reactions one to eighteen months after vaccination. It was observed that the vaccines which had a relatively high potency at the time of lyophilization maintained their ability to induce allergy for at least two years.

Allergens↗

PubMed1956

Effect of adjuvant on preservability of dried BCG vaccine at 37 degrees C.

Experiments were carried out to determine the effect of various adjuvants on the preservability of dried BCG vaccine at 37 degrees C. The substances tested included carbohydrates, proteins, amino-acid derivatives, synthetic polymers, peptides and polypeptides, and various combinations of protein, sugar, and salt.The resulting vaccines were preserved for periods of up to 8 months at 37 degrees C, and were then subjected to culture tests. The highest BCG survival-rate was obtained with sodium glutamate vaccine, no significant difference being observed between the survival-rates with l- and with dl-sodium glutamate. Of the three concentrations of sodium glutamate tested-that is, 1%, 5%, and 10%-the 1% concentration gave the highest survival-rate.From the results obtained with 1% sodium glutamate as adjuvant-a survival-rate per original suspension of about 10% and a viable-unit level of about 10 in 10(-6) mg of bacilli after 6-8 months' preservation-it may be concluded that it is possible to produce a dried BCG vaccine the viability of which will not be adversely affected by storage for several months at room temperature, even in hot climates.

BCG Vaccine↗

PubMed1956

Effect of storage at 37 degrees C on immunizing power of dried BCG vaccine.

Experiments were carried out to determine the effect of storage at 37 degrees C on the immunizing power of dried BCG vaccine. Vaccines were prepared with sodium glutamate and with sucrose, and were preserved for 6 months at 5 degrees C and at 37 degrees C. The preserved vaccines were then injected into four groups of 12 tuberculin-negative guinea-pigs; a fifth group of 12 non-vaccinated animals acted as controls. Six weeks after inoculation, all surviving animals were given a challenge dose of virulent human tubercle bacilli. After a further six weeks the guinea-pigs were killed, and an examination was made of the macroscopic and histological changes produced in the lymph-nodes and viscera.No significant difference in the tuberculous changes induced by the challenge infection was observed among three of the groups of vaccinated animals-namely, the two inoculated with the sodium glutamate vaccines and the one inoculated with the sucrose vaccine preserved at 5 degrees C. The fourth vaccinated group showed greater changes than the other three, indicating that the immunizing power of the sucrose vaccine had decreased markedly during storage for 6 months at 37 degrees C. The non-vaccinated control group, however, showed the most conspicuous changes of all the five groups.

Animals↗

PubMed1955

Study on homogeneous BCG suspensions prepared with tween 80.

The authors describe a new and simple method of preparing homogeneous suspensions of BCG from Sauton cultures by the chemical action of Tween 80. Higher concentrations of bacterial suspensions were obtained with this method than with any other methods employed up to the present. The harmful effect exerted on living bacilli and the decrease in viability during preservation were slighter in the vaccine prepared with Tween 80 than in that prepared by the ordinary grinding method.

BCG Vaccine↗

PubMed1955

Dried BCG vaccine.

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BCG Vaccine↗