[Immunoenzyme analysis in a system of serologic evaluation of louse-borne typhus vaccines].

The blood sera of persons immunized with different typhus vaccines have been studied in the complement fixation test, the indirect hemagglutination test and the enzyme immunoassay. The data thus obtained indicate that the enzyme immunoassay is highly sensitive and can be universally used for the determination of antibodies to Rickettsia prowazekii after primary and booster immunization with different typhus vaccines. This method detects specific antibodies both at an early period and, which is of particular importance, at a remote period after immunization (3 years later) when complement-binding and hemagglutinating antibodies are absent. This is seemingly indicative of the two-phase character of postvaccinal immunity induced by live typhus vaccine.