Mapping of immunoreactive antigens of Francisella tularensis live vaccine strain

Abstract

Francisella tularensis subsp. holarctica is the common causal agent of tularemia in Europe. Besides clinical signs, the diagnosis of the disease mostly depends on serological tests. To date, there is a lack of information about the F. tularensis antigens that induce antibody response. Therefore, we have started comprehensive mapping of immunoreactive antigens using the attenuated live vaccine strain of F. tularensis LVS originating from the European virulent strain. For this purpose, the immunoreactivity of sera collected from patients suffering from tularemia, together with the control sera of patients with Lyme disease and healthy blood donors, were examined by means of one-dimensional and two-dimensional immunoblotting. Furthermore, whole cell bacterial lysates, isolated integral membrane proteins and basic proteins were exploited as antigens. By this approach more than 80 different immunorelevant antigens were detected. Most of them came from whole cell bacterial lysate and integral membrane proteins. Conversely, only a negligible reaction was found in the case of basic proteins. Forty-five spots were further selected for mass spectrometric analyses and 22 of them were annotated. Among the spots that provided characteristic reactions with sera from patients with tularemia, 60 kDa and 10 kDa chaperonins that occurred in several charge and mass variants, predominated.

Modulation of virulence factors in Francisella tularensis determines human macrophage responses

“…6). Previous Francisella proteomics studies have catalogued LVS protein profiles [29,30], immune reactive proteins [31], or stress response proteins [32]. A proteomic comparison of three Francisella strains has been performed, identifying many protein differences [33].…”

ATP-Binding Cassette Transporters Are Targets for the Development of Antibacterial Vaccines and Therapies

“…The finding that there are proteins which are apparently not surface located yet can induce good antibody responses may appear to be paradoxical. However, there are many examples of antibodies in convalescent sera which are directed to cytoplasmic proteins (28,39,48,78). In the case of some proteins, such as Hsp60, this may reflect the surface location of at least part of the protein population (24,29).…”

Identification of In Vivo-Expressed Immunogenic Proteins by Serological Proteome Analysis of the Bacillus anthracis Secretome

“…To identify such proteins in the complex proteome of a pathogen, assessment of seroreactivity can be combined with proteomic studies for direct selection of proteins that are able to elicit a humoral immune response in the course of bacterial infections. This approach, in which large numbers of proteins separated by two-dimensional electrophoresis (2-DE) are identified by mass spectrometry and probed with immune sera (designated serological proteome analysis [SERPA] [43]), has been used with several bacterial systems for identification of diagnostic markers or vaccine candidates (6,15,20,33,35,36,46,80,82,83) or for determination of specific circulating antibodies and/or disease markers in a variety of pathological states not related to diseases caused by bacteria (7,43).…”