This article is part of the supplement: AIDS Vaccine 2009
Oral presentation
OA011-03. Clusterin, a natural ligand of DC-SIGN present in human semen inhibits HIV capture and transmission by dendritic cells
1 National Reference center for AIDS, Buenos Aires, Argentina
2 Institut Curie, Paris, France
3 Institut de Biologie Structurale, UMR CNRS-CEA-UJF, Grenoble, France
4 Institut de Biologie Structurale, UMR CNRS-CEA-UJF, Grenoble, France
5 UMR CNRS 8576, Unité de Glycobiologie Structurale et fonctionnelle, Lille, France
6 Unité d'Immunologie Virale, Institut Pasteur, Paris, France
7 U932 INSERM, Institut Curie, Immunité et Cancer, Paris, France
Retrovirology 2009, 6(Suppl 3):O9 doi:10.1186/1742-4690-6-S3-O9
The electronic version of this article is the complete one and can be found online at: http://www.retrovirology.com/content/6/S3/O9
| Published: | 22 October 2009 |
© 2009 Sabatte et al; licensee BioMed Central Ltd.
Background
Although sexual transmission represents the main mode of HIV dissemination worldwide, little is known about the influence of semen on viral spread. We have shown that seminal plasma (SP) inhibits both, the attachment of HIV to dendritic cells (DC) and the ability of DC to transmit the virus to T cells. Here, we characterized the inhibitor present in SP and their functional properties.
Methods
Semen samples were collected from healthy donors. SP proteins were analyzed by 2D electrophoresis. DC-SIGN binding proteins were identified by western blot using DC-SIGNfc chimera. Selected spots were cut and clusterin was identified by MS analysis as the inhibitor present in SP. SP clusterin was then purified by affinity chromatography. In all the experiments, HIV was quantified by measurement of p24 antigen by ELISA.
Results
We found that SP clusterin markedly inhibits the attachment of HIV-1 BAL (5 ng p24 antigen) to DC in a dose-dependent mode (1–40 μg/ml), being the percentage of inhibition of 54 ± 11(n = 6, p < 0.05) when used at a concentration of 15 μg/ml. Similar levels of inhibition were observed using blocking antibodies directed to DC-SIGN. In transmission experiments DC were cultured with HIV-1 BaL (5 ng p24Ag) in the presence of clusterin (20 μg/ml), washed and cultured with activated peripheral blood mononuclear cells (PBMCs). Clusterin markedly prevented virus transmission to DC: % inhibition = 59 ± 17, n = 5, p < 0.05). Experiments performed with THP-1-DC-SIGN+ cells showed that clusterin, at a concentration of 15 ug/ml, almost completely inhibited both, the attachment of HIV (% inhibition < 87%, n = 5) and the ability of THP-1-DC-SIGN+ cells to transmit the virus to activated PBMCs (% inhibition < 82%, n = 4).
Conclusion
Our results identified clusterin, as a novel ligand of DC-SIGN present in human semen able to inhibit the capture and transmission of HIV by DC.