re HIV coreceptor discussion

Shahram Mori smori at
Mon Jan 31 13:04:01 EST 1994

Dear Immunetters,
I got a few opinions on the HIV CD-26 co-receptor theory.However I would like
to make comments on a couple of points Andreas Weimann made in his post. The
question was that if CD26 and CD4 are both required for HIV entry into the
cell, then why do we get HIV infection in cells that lack these two cell
markers.Andreas pointed out that the mechanism of entry is via the Fc
However the last statement backs up my argument. Fc receptor mechanism of
entry is a way in which the virus is brought into contact with CD4, in other
words to bring about a more efficient CD4-gp120 binding. ( Perro et al 1990
J. exp. med. 171 : 1043 and  Robinson et al 1990 Virology 175: 600).
We have evidence that Bowel Epithelial , Renal epithelial and Brain astrocytes
can get infected and these lack Fc receptors on their surfaces ( Along
with CD4).Therefore my first comment still stands. There must be other
receptors or shuttle mechanisms that allow viral entry. i.e. besides CD4 and
Cd26 ( if the latter is involved in viral entry).
I do agree with Andreas that Dr Hovanessian's group could have proven their
theory by trying to fuse gp 120/41 bearing human cells with murine CD4/CD26,
alone or together.This would have been a much better way of proving the idea
that CD26 is a coreceptor.

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P.s Post is better.

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