The main subject of this essay is the analysis of the immunizing properties and possible side effects of DTP (whole cell)-
polio vaccine, which since 1964 is the backbone of the immunization programme in the Netherlands. The concept, that the basis of the immunity conferred by
diphtheria and
tetanus toxoid and inactivated poliovirus is humoral, is now generally accepted. Assessment of the potency of these three components is based on their binding properties to specific immunoglobulines in standard-
antisera. An example is the testing of neutralising
antibodies against the three types of poliovirus in sera obtained from different groups of infants injected with increasing doses of this
vaccine. Side-effects after injecting
diphtheria- and
tetanus toxoids and three types inactivated poliovaccine are negligible. For the
pertussis component of the
vaccine, this is not the case. The standardization of the potency of cellular
pertussis vaccine is still based on the analysis of the protective capacity of a number of plain
vaccine lots in the intercerebral mouse-protection test relative to the protection they confer in children. An international standard
vaccine is available for this purpose, and the potency of individual lots can be expressed in International Units. At present acellular
pertussis vaccines are also available for immunization against this disease. The components of such
vaccines are at least for a number of components, arbitrarily chosen. Recently in a trial in Sweden, a five-component
pertussis vaccine has given a similar protection of infants as a cellular
vaccine of British origin. In addition this
acellular vaccine induced less febrile reactions. However,
acellular vaccines do not protect mice against intracerebral
infection. because producers have decided to omit the "Outer Membrane Complex (OMC) as a component of the
vaccine. In addition it has recently been shown that the presence of the cellular
pertussis component in
DPT vaccine will almost completely suppress
tetanus antitoxins in the
IgE fraction of the serum. This observation could indicate that this suppression is the result of a cellular immunity reaction by components in the bacteria.