Max Theiler AND
Jordi Casals
The Rockefeller Foundation Virus Laboratories, New York
1) The serological responses of 29 cases of human yellow feverinfection were studied by hemagglutination-inhibition (HI),complement-fixation (CF) and neutralization (N) tests.
2)The cases were divided into two groups, chiefly accordingtothe pattern of CF antibodies to a variety of Group B agents.The 17 cases in the first group are considered to be primaryinfections of yellow fever; the 12 cases in the second are consideredto be infections of yellow fever in individuals who had previouslybeen infected with another Group B virus.
3) In primary infectionsof yellow fever specific HI antibodiesappear first, followedrapidly by antibodies to other GroupB viruses. The titers ofhomologous HI antibodies are alwaysas high as, or higher than,the titers of heterologous antibodies.
4) In primary infectionsthere is great variation in the timeafter onset at which CFantibodies become demonstrable. Complement-fixingantibodiesare produced over a long period and may still beincreasingwhen HI antibodies are diminishing. The pattern ofCF antibodiesis remarkably specific. Overlaps with other antigensoccur onlywhen the homologous CF antibodies are high.
5) In primaryinfections the development of N antibodies asdetermined bythe standard intracerebral test is quite specific.HeterologousN antibodies are developed to a limited extent.
6) In casesof secondary infection, the production of HI andCF antibodiesis both massive and very rapid. There is no suggestionof specificityin the patterns developed and, in fact, as arule the highestHI and CF antibodies were heterologous. Furthermore,in secondaryinfections the production of heterologous N antibodiesis stimulatedto a greater extent than in primary infections.In the present12 cases, the heterologous response was so greatthat in allbut one of the cases accurate diagnosis of the currentillnessby N test was impossible.