Infecção experimental e transmissão horizontal de Bartonella henselae em gatos domésticos

In order to study B. henselae transmission among cats, five young cats were kept in confinement for two years, one of them being inoculated by SC route with B. henselae (10(5) UFC). Only occasional contact among cats occurred but the presence of fleas was observed in all animals throughout the period. Blood culture for isolation of bacteria, PCR-HSP and FTSZ (gender specific), and BH-PCR (species-specific), as well as indirect immunofluorescence method for anti-B. henselae antibodies were performed to confirm the infection of the inoculated cat as well as the other naive cats. Considering the inoculated animal, B. henselae was first isolated by blood culture two months after inoculation, bacteremia last for four months, the specific antibodies being detected by IFI during the entire period. All contacting animals presented with bacteremia 6 months after experimental inoculation but IFI did not detect seroconversion in these animals. All the isolates from these cats were characterized as Bartonella (HSP and FTSZ-PCR), henselae (BH-PCR). However, DNA of B. henselae could not be amplified directly from peripheral blood by the PCR protocols used. Isolation of bacteria by blood culture was the most efficient method to diagnose infection compared to PCR or IFI. The role of fleas in the epidemiology of B. henselae infection in cats is discussed.Procurou-se verificar a possibilidade de transmissão horizontal de B. henselae em 5 felinos confinados, dentre os quais apenas um foi inoculado experimentalmente por via subcutânea (SC) com 10(5) UFC. Todos os felinos apresentavam infestação por pulgas. Para a avaliação da infecção foram utilizados: isolamento bacteriano (hemocultura), detecção de DNA específico pela Reação em Cadeia da Polimerase (PCR), com os protocolos HSP, FTSZ e BH-PCR, e a pesquisa de anticorpos específicos por Imunofluorescência Indireta (IFI). Os protocolos da PCR foram também utilizados para a caracterização do isolado da hemocultura. A inoculação de B. henselae resultou na infecção assintomática do animal inoculado, comprovada através da soroconversão e de bacteremia de 4 meses de duração, com o isolamento da bactéria na hemocultura. Todos os animais contactantes apresentaram bacteremia 6 meses após a data de inoculação experimental. No entanto, não apresentaram reação de IFI positiva. Em nenhum momento foi possível detectar DNA de B. henselae no sangue circulante, com as PCR utilizadas. Não obstante, a PCR possibilitou a identificação da bactéria isolada como sendo do gênero Bartonella (HSP e FTSZ-PCR) e espécie henselae (BH-PCR). Conclui-se que o isolamento bacteriano por meio da hemocultura constitui-se no método mais eficiente para a identificação dos felinos infectados e bacterêmicos. Estes resultados também evidenciam a possibilidade do papel das pulgas na transmissão de B. henselae em gatos

Monocyte-Derived Dendritic Cells Can Revert In Vitro Antigen-Specific Cellular Anergy in Active Human Paracoccidioidomycosis

We investigated the in vitro effects of two Paracoccidioides brasiliensis antigens on monocyte-derived dendritic cells (moDCs) from patients with paracoccidioidomycosis (PCM). MoDCs from patients with active or treated PCM and non-PCM subjects were generated, stimulated with TNF-α, and P. brasiliensis antigens, 43 kDa glycoprotein (gp43) and cell-free antigen (CFA), and analyzed by flow cytometry and enzyme-linked immunosorbent assays (ELISA). Our data revealed that patients with PCM had a high frequency of HLA-DR+ cells, but the treated group had more CD86+ cells with increased IL-12p40. Patients with active PCM had more CD80+ moDCs, and as a novel finding, large amounts of chemokine (C-C motif) ligand 18 (CCL18) in the supernatants from their in vitro moDC cultures. Both gp43- and CFA-stimulated moDCs from the patients with PCM successfully reverted the in vitro antigen-specific anergy, inducing a proliferative response. However, CFA-stimulated moDCs led to higher lymphoproliferation, with increased IFN-γ and TNF-α in the cells from the patients with active PCM compared with gp43. These original results combined with constant IL-10 and increased IL-12p40 levels suggest that a more complex antigen, such as CFA, may be a better inducer of the protective Th1 immune response than purified gp43 is, and a suitable target for future studies on anti-P. brasiliensis dendritic cell (DC)-based vaccines