Biology Reference
In-Depth Information
detected intracellular p24 in both ACH2 and J1.1 cells (data not shown). With
EAS technology, the question of viral latency might be more de®nitively ad-
dressed.
Recognition of Chemokine/Cytokines and Their Receptors
Chemokines and cytokines and their receptors are important players in HIV-1
disease pathogenesis. Most importantly, chemokine receptors serve as co-
receptors with CD4 for HIV-1 infection of cells. The signi®cance of chemokine
receptors is validated by the relative resistance of persons with a 32-bp deletion
in the gene encoding the CCR5 receptor (Sampson et al., 1996). Moreover, a
valine to isoleucine substitution at position 64 in the CCR2 receptor has been
associated with a signi®cant delay in HIV-1 disease progression (Kostrikis et
al., 1998).
Production of chemokines has also been shown to in¯uence HIV-1 disease
pathogenesis. Again, genetic analysis has provided important results that help
to substantiate the role of chemokines. A common genetic polymorphism of
stromal-derived factor-1, which is the principal ligand for CXCR4, an impor-
tant HIV-1 coreceptor, was found to be associated with delayed disease pro-
gression ( Winkler et al., 1998). Furthermore, b-chemokines inhibit the replica-
tion of HIV-1 in vitro (Arenzana-Seisdedos et al., 1996; Bleul et al., 1996;
Oberlin et al., 1996; Schols et al., 1997). These ®ndings are likely to be signi®-
cant because spontaneous and antigen-induced production of HIV-inhibitory b-
chemokines by PBMC from HIV-1-infected persons has been found to be as-
sociated with better clinical status (Garzino-Demo et al., 1999; Saha et al., 1998).
The roles of chemokines and their receptors in the pathogenesis of HIV-1
disease indicate the importance of analyzing these molecules; however, both the
chemokines and their receptors are di½cult to assess. Chemokines are highly
active molecules and are produced and secreted in small quantities. There
are few reports of successful analysis of chemokines using ¯ow cytometric
analysis for intracellular antigens. A search of the PubMed database revealed
only one such reference, which involved the analysis of IL-8 in human mast
cells (Grutzkau et al., 1997). Nevertheless, these investigators were not stim-
ulating the production of the chemokine; mast cells store these substances in
secretory vesicles. For lymphocytes and monocytes that are stimulated to pro-
duce chemokines, the di½culty in assessing production using ¯ow cytometry for
intracellular antigens may be signi®cant. The absence of publications describing
this technology suggests that it has been di½cult to obtain high-quality data
with the available protocols. It is likely that the di½culty in assessing cells for
the production of chemokines involves the poor sensitivity of the standard
procedures of ¯ow cytometric analysis. Consequently, EAS may enable inves-
tigators interested in HIV-1 disease pathogenesis to assess chemokine produc-
tion in lymphocytes and monocytes.
Likewise, chemokine receptors are expressed and are active in low copy
