Biology Reference
In-Depth Information
T A B L E 3.2. Correlation Between Changes in Thymus Volume and T-Cell
Subsets After 12 Months of Potent Antiretroviral Therapy
CD28
CD28 is a disul®de-linked homodimeric glycoprotein that is expressed on the
majority of human CD4
T cells and in 50% of CD8 T cells. CD28 expression
augments after T-cell stimulation. CD28 binds to CD80 and CD86 on the sur-
face of antigen-presenting cells; the interaction between these molecules delivers
signals that augment T-cell responses to antigens. CD8
CD28
T lymphocytes
were suggested to have a pivotal role in the control of the progression of HIV
infection as these cells have been shown to produce cell-antiviral factor (CAF ),
a soluble factor that can suppress HIV replication by blocking the transcription
of viral RNA ( Barker et al., 1997, 1998). The production of CAF diminishes in
the progression of HIV disease (Blackbourn et al., 1996); an expansion of CD4
and CD8 T lymphocytes that do not express CD28 is observed as well in pro-
gressing patients (Kammerer et al., 1996). A tight correlation between the ex-
