Acellular and whole-cell pertussis vaccines in Japan. Report of a visit by US scientists.

Since the introduction of acellular pertussis vaccines in Japan late in 1981, more than 20 million doses have been administered, mostly to children 2 years of age and older. Clinical studies indicate that mild local and febrile reactions are less frequent after administration of acellular pertussis vaccines than after whole-cell vaccines. Serious adverse events with sequelae occurred in 2-year-old children at approximately the same low rate during the period 1975 through August 1981, when whole-cell vaccines were used, and during August 1981 through 1984, when acellular vaccines were used exclusively. Five household contact studies have yielded vaccine efficacy estimates ranging from 78% to 92% in children 1 year of age or older. In addition, there has been a continuing decrease in reported pertussis incidence from the epidemic peak in 1979. Additional data on the safety and efficacy of acellular pertussis vaccines administered to infants would be useful in consideration of acellular pertussis vaccine licensure in the United States.

Effect of tetanus toxin on the accumulation of the permeant lipophilic cation tetraphenylphosphonium by guinea pig brain synaptosomes.

Accumulation of the permeant lipophilic cation [(3)H]tetraphenylphosphonium (TPP(+)) by synaptosome preparations from guinea pig brain cerebral cortex is inhibited 1:10 by medium containing 193 mM K(+) and by veratridine. A further 1:10 to 1:15 decrease in TPP(+) uptake occurs under nitrogen and in the presence of mitochondrial inhibitors such as oligomycin, whereas starvation and succinate supplementation have no effect. These data indicate that, in analogy to intact neurons, there is an electrical potential (DeltaPsi, interior negative) of -60 to -80 mV across the synaptosomal membrane that is due primarily to a K(+) diffusion gradient (K(+) (in)-->K(+) (out)). The data also indicate that mitochondria entrapped within the synaptosome but not free mitochondria make a large contribution to the TPP(+) concentration gradients observed. Conditions are defined in which tetanus toxin binds specifically and immediately to synaptosomes in media used to measure TPP(+) uptake. Under these conditions tetanus toxin induces dose-dependent changes in TPP(+) uptake that are blocked by antitoxin and not mimicked by biologically inactivated toxin preparations. The effect of tetanus toxin on TPP(+) uptake is not evident in the presence of 193 mM K(+) or veratridine but remains under conditions known to abolish the mitochondrial DeltaPsi. Moreover, tetanus toxin has no effect on TPP(+) uptake by isolated synaptosomal mitochondria. The results thus define an in vitro action of tetanus toxin on the synaptosomal membrane that can be correlated with biological potency in vivo and is consistent with the in vivo effects of tetanus toxin on neuronal transmission.