Experimental infection by Chlamydia pneumoniae in the hamster.
We report that intraperitoneal injection of Chlamydia pneumoniae purified elementary bodies (EBs) in the hamster causes a systemic infection allowing the isolation of viable chlamydiae from several organs for several days post-infection (p.i.). In particular, spleen infection occurred up to Day 7 p.i. in 100% of animals. Systemic infection probably occurs via macrophages as intraperitoneally injected chlamydiae which are taken up by the hamster macrophages remain viable and can infect in vitro cell cultures. Immunization of 18 hamsters with heat-inactivated purified EBs, completely protected the spleens of 16 animals and substantially reduced infection levels in the remaining two. This model, therefore, provides a robust screening tool for the assessment of the protective activity of potential vaccine candidates. In a pilot study on five recombinant antigens recently described as EB surface proteins, three gave results undistinguishable from non-immunized, or mock-immunized controls; however two antigens, derived, respectively, from the product of the lcrE gene (a component of the putative TTSS of C. pneumoniae) and the product of Cpn0498 open reading frame, proved to be capable of inducing protective immune responses.
Sezione di Microbiologia DMCSS, University of Bologna, Ospedale Policlinico S.Orsola, Via Massarenti 9, 40138 Bologna, Italy.
Vittorio
V
Sambri
Manuela
M
Donati
Elisa
E
Storni
Korinne
K
Di Leo
Mauro
M
Agnusdei
Roberto
R
Petracca
Oretta
O
Finco
Guido
G
Grandi
Giulio
G
Ratti
Roberto
R
Cevenini
D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis / Q000276:immunology; D000942:Antigens, Bacterial / Q000276:immunology; D002690:Chlamydia Infections / Q000276:immunology* / Q000382:microbiology; D016993:Chlamydophila pneumoniae / Q000276:immunology / Q000472:pathogenicity; D006224:Cricetinae; D004195:Disease Models, Animal; D016650:Fluorescein-5-isothiocyanate; D005455:Fluorescent Antibody Technique; D005456:Fluorescent Dyes; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D017737:Macrophages, Peritoneal / Q000276:immunology; D008647:Mesocricetus
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D005456:Fluorescent Dyes; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016650:Fluorescein-5-isothiocyanate