HIV-Inhibiting Chemokines: Critical Host Factors in AIDS

ZRG-1 AARR-02 (01) 7 1R01AI48384-O1A1
July 2000 GARZINO-DEMO, A
different forms of MDC are not addressed.
Most concerning, there is no effort made to attempt to define the cell
population responsible for production of beta chemokines following
antigen-specific stimulation. This is an essential step if the investigators
are to translate this association of unknown biologic significance into an
immunologic mechanism. The Principal Investigator's five reasons for not
pursuing these studies are unconvincing. Specific studies in a subgroup of
patients could be carried out to determine the cell population involved.
Although it is not possible to assess production of MDC or LD78 beta by flow
cytometry, flow cytometric assays are established for MIP-1 alpha and beta,
chemokines that have been shown to correlate with disease status. These studies
could be easily carried out in parallel with the planned prospective study
rather than waiting five years to pursue these studies after the current grant
is completed.,
The second specific aim will analyze potential changes in chemokine receptor
usage over time. These experiments have been significantly improved by the
shift from the previous analysis of syncytia formation to the use the U373 cell
line transfected with individual chemokine receptors. However, there is
continued concern as to whether the investigators will be. able to get useful
data using this approach,"especially for patients on HAART, and no preliminary
data provided demonstrating the utility of this particular cel.l line for
analyzing chemokine receptor usage of clinical isolates. The proposed
amplification of V3 loop, followed by sequencing or subcloning into HXB2 in
part addresses this concern, but these are labor intensive techniques and no
means is provided for prioritizing which samples will be analyzed in this
fashion.
Innovation: The primary aim of this proposal is to extend prior observations
into a new clinical cohort which will be followed prospectively. As such, there
are no significantly innovative features of this proposal..
Investigators: Dr. Garzino-Demo is a junior but well experienced scientist who
has considerable prior expertise in the analysis of chemokines, including prior
conduct of similar studies with the MACS cohort. His qualifications are overall
excellent. The application is also considerably supported by the efforts of Dr.
Margolick, whose considerable experience with the MACS cohort also represents a
significant strength.
Environment: The Institute of Human Virology has a longstanding interest in the
role of chemokines in AIDS pathogenesis and is an excellent environment in
which to conduct these studies. Adequate facilities for biocontainment are _
provided. Assays to address chemokine receptor usage and better description of
the clinical cohort to be studied. However, many significant weaknesses remain,
including the limitations inherent in carrying out a descriptive study without
defining the specific cell populations that underlie these observations,
concerns that the MACS cohort will not be sufficiently powered to observe a
significant effect, and the difficulties inherent in trying to establish
whether chemokine production merely correlates with another more important
disease parameter or whether it plays a causal role in vivo in controlling
viral replication.