Eight chimpanzees were fed and/or inoculated with a single Coxsackie (C) virus or combinations of different ones. The responses in terms of complement-fixing (c-f) antibodies to 6 to 10 such viruses were measured throughout periods of 1 to 2 years. Although the animals usually responded with rises in homologous antibodies after the feeding or the inoculation of viruses of special immunological types, a variable number of heterologous c-f antibodies were observed to increase significantly at the same time.
When immune animals were challenged with homologous virus, they failed to become virus carriers again and no rises in neutralizing antibodies were detected. However, the challenge usually resulted in a boost in the titer of the homologous c-f antibody and often of heterotypic c-f antibodies. This was particularly striking in those chimpanzees in which the c-f antibody had fallen below a detectable level.
In contrast to this, the infection of chimpanzees with agents outside the Coxsackie family (poliomyelitis viruses and Egyptian strains of West Nile virus) failed to influence the level of Coxsackie antibodies even during the periods when c-f antibodies to these non-Coxsackie viruses were rapidly rising.