Biomedical subjects

Vittorio Sambri

Publications and source records attributed to Vittorio Sambri.

4 recordsLinked to original sources

PubMed2003

Phagocytosis of Treponema pallidum and reactive oxygen species production by isolated rat Kupffer cells.

The in vitro phagocytosis of viable Treponema pallidum subsp. pallidum by isolated rat Kupffer cells, studied by immunofluorescence staining of Kupffer cells-associated bacteria, showed that ingestion of live, unopsonized treponemes was slow: in fact, Kupffer cells started to be positive 1 h after infection, when only 4% of the cells presented small round fluorescent inclusion-like bodies. Thereafter, the number of positive cells progressively increased with time: 7%, 17%, 36%, and 69% of Kupffer cells were positive, respectively, 2, 4, 6 and 8 h after infection. Opsonization of T. pallidum with human immune serum did not substantially modify the percentage (8%) of Kupffer cells ingesting T. pallidum 1 h after infection, whereas opsonization significantly ( P<0.01) increased phagocytosis after 2, 4 and 6 h of incubation, when 44%, 58%, and 68% of Kupffer cells were positive, respectively. At 8 h after infection of Kupffer cells by opsonized T. pallidum, 75% of the cells were positive by immunofluorescence. Heat-inactivation of T. pallidum slightly enhanced phagocytosis. In contrast, opsonization of heat-inactivated spirochetes with specific antibodies significantly ( P<0.01) increased the phagocytosis of bacteria by Kupffer cells, beginning as early as 30 min after infection, when 65% of the cells were positive by immunofluorescence. The reactive oxygen species (ROS) production by Kupffer cells following incubation with spirochetes was also determined by chemiluminescence. Treponemes induced an oxidative burst in Kupffer cells in a dose-dependent manner and the generation of ROS was already detectable 20 min after the exposure of the Kupffer cells to treponemes and peaked at 35 min of incubation. Live, as well as live and opsonized, and heat-inactivated treponemes, induced an O(2)(-) production lower than that induced by heat-inactivated and opsonized spirochetes.

Animals↗

PubMed2003

DNA immunization with pgp3 gene of Chlamydia trachomatis inhibits the spread of chlamydial infection from the lower to the upper genital tract in C3H/HeN mice.

Chlamydia trachomatis pgp3 DNA immunized (no. 300) and non-immunized (no. 300) C3H/HeN mice were infected by vaginal inoculation with infectious C. trachomatis serotype D elementary bodies (EBs) and the spread of infection to the salpinges was assessed by cell culture isolation from tissue homogenates 7, 14, 21, 28, 35 and 42 days post-infection (p.i.). Overall, the pgp3-DNA immunization prevented salpinx infection in 94 (56%) mice, if compared with the 168 positive animals found among the non-immunized animals (P < 0.001). A group of negative control animals (i.e. mice immunized with plasmid DNA containing an irrelevant insert) was not protected, whereas all the mice of a positive immune control group (mice that had resolved a primary genital C. trachomatis infection) were resistant to re-infection. Pgp3 DNA immunization induced both humoral and mucosal anti-pgp3 antibodies.

Animals↗

PubMed2002

Chlamydia trachomatis - the agent.

Chlamydiae are obligate intracellular bacteria, parasitizing eukaryotic cells. Chlamydia trachomatis, C. psittaci and C. pneumoniae are the three species of chlamydiae pathogenic to humans. C. trachomatis shows a tropism for the genital and conjunctival epithelia and consists of 19 different serovars which are pathogenic predominantly for the urogenital tract.A distinguishing feature of chlamydiae is their transition between the infectious elementary body that enters the host cell and the non-infectious reticulate body that replicates intracellularly within an inclusion that does not fuse with lysosomes. Chlamydiae depend for some functions upon the host cell; in particular, chlamydiae have little capacity for generating energy. The complete sequence of the 1000-kb chromosome of C. trachomatis is known, as are most of the genes located on the 7.5-kb cryptic plasmid. Recently, several concepts about the biology and the metabolic pathways of C. trachomatis have been revised in relation to the genome sequence, and different novel proteins have been described.

Chlamydia Infections↗

PubMed2002

Comparative in vitro activity of five cathelicidin-derived synthetic peptides against Leptospira, Borrelia and Treponema pallidum.

OBJECTIVE: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of five different cathelicidin-derived synthetic peptides (SMAP-29, LL-37, PG-1, CRAMP and BMAP-28) for Leptospira interrogans, Borrelia spp. and Treponema pallidum subsp. pallidum were investigated in vitro. METHODS: The MIC of individual peptides was defined as the lowest concentration able to inhibit the motility of spirochaetes after 2 h of incubation, as detected by dark-field microscopy. The MBC of individual peptides was defined as the lowest concentration at which no spirochaetes were subcultured either in cathelicidin-free medium (leptospires and borreliae) or in hamsters (T. pallidum). RESULTS: The MIC values of peptides for leptospires were highly variable, depending on the compound and the strain used. Of the five cathelicidin-derived peptides, SMAP-29 from sheep and BMAP-28 from cattle were the most active against L. interrogans serovars, with MIC values varying between 3 and 51 mg/L, depending on the strains. The MICs of the remaining synthetic peptides ranged between 4.3 and 224 mg/L. The MIC values of synthetic peptides for T. pallidum ranged between 32.3 mg/L for PG-1 and 449.4 mg/L for LL-37. The MICs of all cathelicidin-derived peptides tested for Borrelia strains ranged between 307 and 449.4 mg/L. The activity of the peptides on the motility of spirochaetes was both dose- and time-dependent. The MBC values of the peptides were the same as the MIC values. CONCLUSION: The results of this study demonstrate that the activity of cathelicidin-derived peptides against spirochaetes is fast and highly variable, depending on the species and the strain.

Animals↗