Reisaku Kono

The trend of acquired immunity with live poliovirus vaccine and the effect of revaccination: follow-up of vaccinees for ten years

The persistence of neutralizing antibody (NA) against three types of poliovirus acquired after two doses of trivalent live attenuated poliovirus vaccine (LPV) has been followed up for ten years in individual vaccinees. Sixty-seven children were bled once a year over a five year period following the primary vaccination. More than 80% of them retained NA against all three types of poliovirus. Thirty-two individuals whose NA titres were 1:16 or over for types 1 and 2 and 1:4 or over for type 3 at the fifth year were further followed up for a further five years and it was shown that during this period some of them had a naturally-acquired antibody rise, mostly against type 3 virus. At the sixth to eighth year after the primary vaccination, one further dose of the trivalent vaccine was administered to the children whose NA titres were down to 1:8 or less and the effect of booster vaccination on NA was followed. Other subjects were revaccinated with LPV and their fecal excretion of the vaccine virus was investigated. The results showed that a decrease in serum antibody level could be a good indicator of the local resistance of the alimentary tract and that reinfection could occur if serum NA had decreased to 1:8 or less, which allowed a virus excretion in the stools.

The ten year follow-up of the persistence of humoral antibody to rubella virus acquired by vaccination with the Japanese To-336 vaccine

Haemagglutination inhibition (HI) antibodies against rubella virus have been followed in vaccinees for ten years after the vaccination with a rubella vaccine prepared by attenuation of a Japanese rubella virus, strain To-336. The results were as follows: the geometric mean titre (GMT) of HI antibodies was 1/94.4 in 50 vaccinees examined six weeks after the vaccination; it was 1/78·2 in the 17 individuals who were still accessible ten years after vaccination. Since the rubella HI antibody titres induced by the To-336 vaccine were comparable with those acquired by natural exposure, it is considered that the To-336 rubella vaccine ensures a long lasting immunity.

GROWTH CHARACTERISTICS OF ADENOVIRUS TYPES 1 AND 3 IN HELA CELLS

Adenovirus was first recovered from tissue cultures of healthy human adenoidal tissue in 1953. The etiological roles of Adenovirus have been elucidated in many human diseases thereafter. On the way of these studies, characteristical features of this virus had attracted a great deal of attention of many investigators. Although many data on these characteristics have been accumulated, many problems still remain to be solved in the future.This paper reports the results of our experiment which tried to detect the localization of growth site of Adenovirus in HeLa cells by fractionation of the cells into nucleic and cytoplasmic ones. Three fractions obtained, nucleic, cytoplasmic and culture fluid, were titrated their infectivity and complement fixing-antigen successively in time. At the sane time, morphological changes of the infected cells were observed.Almost the same experiment was independently reported by Ginsberg, but he did not show growth curve of three cellular fractions timmsequentially.Experimental materials and method: Adenovirus types 1 (Ad, 71) and 3 (G, B) and HeLa cells were used as experimental materials. HeLa cells infected with Adenovirus type 1 or 3 were sequentially fractionated into nucleic and cytoplasmic fractions with treatment of 2.5% citric acid and centrifugation; of these fractions the infectivity and complement-fixing antigenicity were titrated. Paralleled to these procedures, infected HeLa cells, cultured on cover slips, were stained with hematoxylin and eosin after fixation with 95% methanol and observed the morphological changes under a light microscope.Summary:1) At the first time, influences of fractionating procedures upon infectivity, complement-fixing antigenicity of Adenovirus and upon HeLa cells themselves were tested. It was revealed that there was no influence of the procedures upon infectlvlty and complement-fixing antigenicity and that loss of number of HeLa cells by such procedures were under 10% of the starting number.2) Infectivity and comlement-fixing antigenicity in HeLa cells infected with Adenovirus type, 1 or 3 were always higher in cytoplasmic than in nucleic fractions. In all cases, infectivity appeared earlier than complement-fixing antigenicity in both cytoplasmic and nucleic fractions. In fluid phase, infectivity and complement-fixing antigenicity were detected later than intracellular ones, and increased after the time when intracellular antigenicities began to decrease.3) Morphological changes of HeLa cells infected with Adenovirus type 1 were mostly predominent in the nucleus. According to the sequential features of nucleus, they were classified into first, middle and late stages.