FR AA 0103

Selective transmigration of monocyte-associated HIV-1 across a human cervical monolayer and its modulation by seminal plasma

Presented by Olivier Delezay (France).

T. Bourlet¹, P. Lawrence¹, D. Portran¹, S. Palle², T. Olivier², J. Fantini³, B. Pozzetto¹, O. Delezay¹

¹GIMAP EA 3064, IFR 143 University of Saint-Etienne, University of Lyon (PRES), Faculty of Medicine, Saint-Etienne, France, ²Centre de Microscopie Confocale Multiphotonique, University of Saint-Etienne, University of Lyon (PRES), Pôle Optique et Vision, Saint-Etienne, France, ³CNRS UMR 623, University of Aix-Marseille, Laboratoire des Interactions Moléculaires et Systèmes Membranaires, Marseille, France

Background: Transmigration of human immunodeficiency virus type 1 (HIV-1)-infected leucocytes through female genital mucosa is one of the mechanisms proposed for the heterosexual transmission of this virus. After sexual intercourse, a selection process has been shown to leadto a predominant transmission of the R5 phenotype despite the presence of X4 and R5 strainsin semen. Transmigration of HIV-infected monocytes present in semen may represent apertinent mechanism that could explain this tropism selection.
Methods: In this study, we have analysed the transmigration of monocyte-enriched PBMCs (PBM) and lymphocyte-enriched PBMCs (PBL) immune cells across the epithelial monolayer using the endometrial HEC-1A cell line seeded on inserts (pore size of 0.3µM). The transmigration assay was performed over 24h and transmigrated cells were analysed by flow cytometry, p24 Ag quantification and proviral DNA amplification. In some experiments, confluent HEC-1A cell culture inserts used in transmigration assays were fixed in paraformaldehyde, immunostained before fluorescent or confocal microscopy analysis.
Results: Monocytes, representative of the main immune cell type found in semen, were found able to efficiently cross the cellular monolayer, in contrast with lymphocytes. The measurement of the epithelial crossing of infected cells revealed the preferential passage of the R5 strain HIV-1BaL associated with monocytes. In contrast, HIV-1Mn-infected immune cells were not detected in the basal compartment of confluent HEC-1A cell culture inserts. Seminal plasma increased transepithelial resistance of a tight HEC-1A epithelial monolayer and accordingly reduced leucocyte transmigration.
Conclusions: These observations are in agreement with the hypothesis that transmigration of monocytes could be involved in the selective transmission of monocytotropic HIV strains. This phenomenon could contribute to the negative selection of X4 strains during heterosexual transmission. Overall, our results argue in favour of transmigration of infected monocytes in the selective transmission of HIV-1.

Links:

• Delezay et.al. – FRAA0103
• Slides mit Audio
• Präsentation (.ppt)