Biology Reference
In-Depth Information
8
Gamma-Delta (
gd
) T Cells and HIV-1
Infection
Roxana E. Rojas and W. Henry Boom
Division of Infectious Diseases, Case Western Reserve University, Cleveland,
Ohio, USA
GENERAL OVERVIEW OF
gd
T-CELL BIOLOGY
This review on gd T cells in human immunode®ciency virus 1 ( HIV-1) infection
will focus, unless otherwise indicated, primarily on human T cells. It is aimed at
providing the tools to understand the role of gd T cells in HIV infection.
ab T cells, B cells, and gd T cells constitute the three lymphocyte lineages
present in all jawed vertebrate species. Among CD3
T cells, gd T cells were
the most recently described lymphocyte subset. Since the original description of
the T-cell receptor ( TCR) g chain in 1984 and the isolation of a second hetero-
dimeric TCR in 1986, extensive studies have been performed on the role and
function of gd TCR-bearing cells in human immune responses (Bank et al.,
1986; Born et al., 1987; Brenner et al., 1986; Chien et al., 1987; Pardoll et al.,
1987; Saito et al., 1984; Weiss et al., 1986). Considerable progress has been
made during the last decade, resulting in signi®cant understanding of many bio-
logical and functional features of this T-cell subset. However, a large number
of issues in the gd T-cell ®eld remain unresolved, such as the manner in which
antigens are processed and presented to gd TCRs.
It has been proposed that gd TCR genes are phylogenetically more primi-
tive than the ab TCR genes (Herzenberg, 1989; Richards and Nelson, 2000).
However, other authors propose that there is no substantial evidence to sup-
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