Microimmunofluorescence and Western immunoblotting were compared with the classical
complement fixation reaction and the Weil-Felix test to study the serological responses of patients to Rickettsia prowazekii and both Proteus vulgaris OX19 and OX2 during primary and recrudescent
typhus infections. The serological response to R. prowazekii was found to be similar during primary and recrudescent
typhus, and all sera examined contained
antibodies to the same R. prowazekii cell structures.
Immunoglobulin G (
IgG) and
IgM were found to be the dominant anti-R. prowazekii
immunoglobulins in all sera tested and were found to be directed against the 100-kDa
protein and the
lipopolysaccharide.
IgA antibodies, when present, were mainly against the 100-kDa
protein. For P. vulgaris,
IgG antibodies recognized the
proteins and
lipopolysaccharides of both OX19 and OX2 serotypes;
IgM antibodies were directed against the P. vulgaris OX2
lipopolysaccharide. In addition, donor blood sera, which were negative by microimmunofluorescence, were found to contain
IgG immunoglobulins reacting with R. prowazekii
protein antigens of 135, 60, and 47 kDa by western immunoblotting.