Public release date: 20-Oct-2005


Contact: Stacie Bloom
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212-342-4159
Journal of Clinical Investigation
Got milk? How breastfeeding affects HIV transmission

Mother to child transmission of HIV accounts for a large proportion of HIV
infections in children, with many infected as a result of breastfeeding,
which requires transfer of the virus across mucosal barriers. DC-SIGN, a DC
lectin receptor, interacts with HIV and is found at high expression levels
in tonsillar tissue.
In a paper appearing online on October 20 in advance of print publication of
the November issue of the Journal of Clinical Investigation, William Paxton
and colleagues from the University of Amsterdam clarify how human milk
affects the HIV interactions with DC-SIGN that occur during breastfeeding.

The authors show that human milk can block the binding of HIV to the DC-SIGN
molecule expressed on dendritic cells and potently inhibit the transfer of
HIV-1 to CD4+ T-lymphocytes. The authors identify the component present in
human milk that binds to DC-SIGN. The inhibitory effect can be fully
alleviated with an antibody recognizing the Lewis X sugar epitope on this
factor. Other major milk proteins do not bind to DC-SIGN nor inhibit viral
transfer. These results demonstrate that protein associated Lewis X is
necessary and sufficient to interact withDC-SIGN and block the interaction
of DC-SIGN and HIV.

The identification of a factor in human milk that can block HIV-1
transmission, the ability of the factor to inhibit the virus from binding to
DCs, and the potential immunomodulatory implications of such a compound has
major implications for the development of agents that can block HIV
transmission.

###
TITLE: Lewis X component in human milk binds DC-SIGN and inhibits HIV-1
transfer to CD4+ T-lymphocytes

AUTHOR CONTACT:
William Paxton
University of Amsterdam, Amsterdam, Netherlands
Phone: +31 20 566 4739; Fax: +31 20 691 6531; E-mail: [log in to unmask]

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