The complement-fixing antibodies present in epidemic and murine typhus immune sera can be differentiated by quantitative absorption tests. The neutralizing antibodies that participate in the Giroud reaction can be differentiated by quantitative inhibition tests.Epidemic and murine typhus immune sera contain two kinds of complement-fixing antibodies and also two kinds of neutralizing antibodies. The antigens that react with these antibodies differ in specificity and thermal resistance. Cross reactions between epidemic and murine rickettsiae are due to the presence of similar heat stable antigens in the two types. Type specific sera may be obtained by absorbing immune serum with either (a) rickettsiae of heterologous type or (b) heated rickettsiae of homologous type. The specific antibodies react only with the heat labile antigens of the homologous type of rickettsiae.Mice may be actively immunized against the toxic factors of murine and epidemic rickettsiae. The immunity produced by small doses of vaccine is type specific and dependent on the presence of heat labile antigen in the vaccine.
This paper describes further laboratory studies undertaken to investigate the immunological aspects of the outbreak of poliomyelitis in the Canadian Eastern Arctic in the winter of 1948-1949. No evidence was found that any of three strains of virus recovered from Eskimos was pathogenic for cotton rats or mice. No strains of Coxsackie virus were recovered. Main attention is directed to the examination of 51 sera from 40 persons (34 Eskimos) involved in the outbreak for the presence of neutralizing antibody to Lansing poliomyelitis virus. Antibody was found in the acute phase serum of two of three patients, and in the con valescent phase serum of about half of those tested. The serum of six of eight healthy Eskimos and five of six white contacts contained antibody. It seemed that antibody started to appear in the serum from the age of 10 onwards, the serum of most adults proving positive. It is concluded that the presence of Lansing antibody in the serum of the Eskimos was the result of previous exposure to Lansing virus and was unrelated to the current epidemic. The world-wide prevalence of Lansing antibody and by inference of Lansing virus is evident.
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