Broadly neutralizing antibodies suppress post-transcytosis HIV-1 infectivity.

Broadly neutralizing antibodies (bNAbs) offer promising opportunities for preventing HIV-1 infection in humans. Immunoprophylaxis with potent bNAbs efficiently protects non-human primates from mucosal transmission even after repeated challenges. However, the precise mechanisms of bNAb-mediated viral inhibition in mucosal tissues are currently unknown. Here, we show that immunoglobulin (Ig)G and IgA bNAbs do not interfere with the endocytic transport of HIV-1 across epithelial cells, a process referred to as transcytosis. Instead, both viruses and antibodies are translocated to the basal pole of epithelial cells, possibly in the form of an immune complex. Importantly, as opposed to free virions, viral particles bound by bNAbs are no longer infectious after transepithelial transit. Post-transcytosis neutralization activity of bNAbs displays comparable inhibitory concentrations as those measured in classical neutralization assays. Thus, bNAbs do not block the transport of incoming HIV-1 viruses across the mucosal epithelium but rather neutralize the transcytosed virions, highlighting their efficient prophylactic and protective activity in vivo.

Conversion of DL-threonine, D-threonine and 2-oxobutyrate into propionate and 2-hydroxybutyrate by Fusobacterium species.

The present investigation examined DL-threonine, D-threonine and 2-oxobutyrate conversion into propionate and 2-hydroxybutyrate by various type strains and clinical isolates of Fusobacterium. Except for Fus. naviforme, the type strains were able to produce varying degrees of propionate and/or 2-hydroxybutyrate from DL-threonine. Additionally, D-threonine was converted into an equimolar amount of propionate by Fus. necrophorum subsp. necrophorum, Fus. nucleatum subsp. nucleatum and Fus. varium, and to a lower but significant amount by Fus. mortiferum and Fus. perfoetens. However, the level of propionate remained unchanged for Fus. nucleatum subsp. fusiforme, Fus. nucleatum subsp. vincentii, Fus. naviforme, Fus. necrophorum subsp. funduliforme, Fus. gonidiaforme and Fus. russii. 2-Oxobutyrate was fermented to propionate by all type strains, although Fus. russii reduced it mainly to 2-hydroxybutyrate. Thus, an attempt was made to make use of these features in order to identify clinical isolates.

[Prostanoids of the peritoneal fluid and sterility with or without pelvic lesions (endometriosis, postinfectious adhesions)]. / Prostanoïdes du liquide péritonéal et stérilités associées ou non à des lésions pelviennes (endométrioses, adhérences post-infectieuses).

Peritoneal fluid levels of 6-keto-PGF1 alpha, TxB2, PGE2 and PGF2 alpha were measured in 62 infertile women undergoing coelioscopy. In 10 patients with mild endometriosis, the levels of all prostanoids were significantly enhanced as compared to control group (15 infertile patients without pelvic lesion). In 5 patients with moderate endometriosis, only PGF2 alpha exhibited a significant enhancement. The results confirmed the prostanoid component alteration of peritoneal fluid in infertile women with mild or moderate endometriosis, which however not has been found by all authors. In 6 patients with chronic salpingitis, no difference was found in prostanoid levels as compared to control group. The 26 patients with pelvic adhesions were distributed in 3 groups on the criterion of easy lysed or not adhesions. In group I (not lysed adhesions, 7 patients), no difference was found in prostanoid levels as compared to control group. In group II (mixed adhesions, 13 patients), the levels of all prostanoids, particularly 6-keto-PGF1 alpha, were significantly higher than that found in control group. In group III (easy lysed adhesions, 6 patients), the levels of 6-keto-PGF1 alpha, TxB2 and particularly PGF2 alpha were significantly enhanced as compared to control group. The results of this study suggest that prostanoids are implicated in physiopathology of endometriosis and pelvic adhesions and perhaps in mechanism of the associated infertility.