Persistence of cell-mediated immunity and decline of humoral immunity to the intracellular bacterium Francisella tularensis 25 years after natural infection.
The humoral and cell-mediated immune responses to the facultative intracellular pathogen Francisella tularensis were studied in subjects who had tularemia 25 years earlier. Serum agglutinin titers were low. Of 53 subjects, only 2 had a titer > 40. The F. tularensis-induced T cell response, on the other hand, was vigorous and in fact similar in magnitude to the response to purified protein derivative (PPD) of Mycobacterium tuberculosis. T cells from 44 of 52 subjects showed a significant (P < .05) proliferative response in vitro to each of four membrane proteins of F. tularensis. Only 2 subjects did not respond to any of the proteins. In most cultures from 18 subjects tested, interferon-gamma was produced in response to the proteins. During the last 25 years, tularemia has been reported only rarely in the region where the subjects lived, suggesting that an antigen-specific T cell response may persist after tularemia independently of reexposure to F. tularensis.
Department of Infectious Diseases, University of Umeå, Sweden.
M
M
Ericsson
G
G
Sandström
A
A
Sjöstedt
A
A
Tärnvik
D000328:Adult; D000368:Aged; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000276:immunology; D005260:Female; D005604:Francisella tularensis / Q000276:immunology*; D006801:Humans; D007111:Immunity, Cellular; D015994:Incidence; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology*; D013997:Time Factors; D014406:Tularemia / Q000453:epidemiology / Q000276:immunology* / Q000503:physiopathology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial