Bridging the Gap: Conference Record [Abstract book, International Conference on AIDS (12th: 1998: Geneva, Switzerland)]

838 Abstracts 42254-42325

12th World AIDS Conference

42321 Co-infusion of autologous HIV-1 specific gene-modified
CD4 and CD8 T cells leads to improved T cell survival
and tissue trafficking
Kristen M. Hege1, S.G. Deeks2, R.T. Mitsuyasu3, P.A. Anton3, D.T. Scadden4,
E. Connick5, D.F. Broad1. 1Cell Genesys, Inc. 342 Lakeside Drive, Foster City,
CA 94404; 2San Francisco General Hospital, San Francisco, CA; 3University of
California, Los Angeles, Los Angeles, CA; 4Massachusetts General Hospital,
Boston, MA; 5University of Colorado, Denver, CO, USA
Background: The antigen specificity of human T cells can be redirected by genetic modification with chimeric immune receptors targeted against viral antigens.
We have genetically engineered T cells with HIV specificity by inserting a gene,
CD4-zeta, containing the extracellular and transmembrane domains of human
CD4 (which binds HIV gp120) linked to the zeta chain of the T cell receptor (involved in T cell activation). In a pilot study performed in HIV discordant syngeneic
twin pairs, CD4-zeta expressing CD8 T cells derived from the uninfected twins
were infused into the HIV infected twins. Although circulating gene-modified CD8
T cells represented 0.5-10% of PBMC 24 hours after infusion of 1010 cells, this
decreased by 1-4 logs within 4 weeks. Since HIV-specific CD4 T cells are missing
in many patients with progressive HIV infection, in vivo survival and function of
modified CD8 T cells may be enhanced by CD4-zeta-modified CD4 "helper" T
cells.
Methods: A clinical trial of autologous CD4-zeta gene-modified CD4 and CD8
T cells (2 x 1010 cells) administered with or without interleukin-2 (6 million IU/24
hours x 5 days) was initiated in 26 HIV infected subjects receiving concomitant
antiretroviral drug therapy with viral loads >1000 copies/ml. T cells were obtained
by lymphapheresis, stimulated ex vivo using immobilized antibodies to CD3 and
CD28, transduced with a CD4-zeta containing retroviral vector, and expanded for
approximately 2 weeks prior to reinfusion.
Results: Transduction efficiencies were 9-49%. The proportion of CD4 T cells
at the end of cell culture was 7-62%. In 5 patients analyzed to date, the mean
percentage of circulating gene-modified T cells was 0.7% (0.2-1.9) of PBMC at
48 hours and 2.4% (0.3-6.6) at 2 weeks post T cell infusion consistent with in
vivo proliferation of gene-modified cells. Subset analysis demonstrated persistence of both gene-modified CD4 and CD8 T cells. Analysis of serial biopsies of
rectal mucosa-associated lymphoid tissue in 2 patients to date demonstrated the
presence of CD4-zeta T cells in both cases with increasing signal from day 1 to
day 7.
Conclusions: Unlike previous clinical trials of adoptive immunotherapy with
HIV specific CD8 T cells alone, co-infusion of autologous CD4-zeta gene-modified
CD4 and CD8 T cells resulted in high level persistence of gene-modified cells in
blood with stable or increasing levels in blood and gut-associated lymphoid tissue
over time. Survival of both gene-modified CD4 and CD8 T cells was demonstrated, consistent with possible resistance of gene-modified CD4 cells to HIV
infection.
346*/42322 In vivo persistence of genetically modified,
HIV-1-specific syngeneic lymphocytes in
HIV-1-discordant identical twins
Robert Walker1, C.M. Bechtel2, V. Natarajan3, R.M. Blaese4, K.M. Hege5,
M.R. Roberts5, H.C. Lane2. 1NIAID/NIH, Bldg. 10, Room 11C103, Bethesda,
Maryland 20892-1880; 2NIAID, Bethesda, MD; 3SAIC/FCRDC, Frederick, MD;
4NHGRI, Bethesda, MD; 5Cell Genesys, Inc., Foster City, CA, USA
Background: Antigen-specific CD8+ T cells can eradicate some experimental
viral infections and may play a role in controlling HIV-1 dissemination. This study
was designed to determine the safety and activity of healthy T cells genetically engineered to express a chimeric receptor ("CD4-zeta") comprised of the
extracellular domain of human CD4 (providing anti-gpl20 specificity) and the
intracytoplasmic domain of CD3-zeta (enabling T cell activation) after transfer to
HIV-1-infected identical twins.
Methods: In an initial phase I/Il study, PBMC obtained from HIV-1-seronegative
donor twins were enriched for CD8+ expression, activated with IL-2 and anti-CD3,
and transduced with a murine retrovirus containing the CD4-zeta gene. Following
dose escalation, 30 HIV-1-infected twins received up to 6 infusions over 1 year
of either 1010 CD4-zeta transduced or control CD8+ T cells. In a second study,
designed to test the effects of providing HIV-1-specific CD4+ T cell help, 17
twins subsequently received 3 additional infusions of 1010 CD4-zeta-modified
CD4+ and CD8+ T cells at 2 week intervals. In this latter study, modified T cells
were stimulated with IL-2 and bead-immobilized anti-CD3 and anti-CD28 prior to
transduction and expansion.
Results: Circulating transduced cells were detected in 21/21 recipients of
gene-modified CD8+ T cells alone, with peak levels of 104 copies/106 PBMC in
16 patients. However, rapid clearance of modified cells (i.e., 3-log reduction within
4 weeks of infusion) was seen in 9 recipients. In contrast, all 17 recipients of
gene-modified CD4+ and CD8+ T cells showed prolonged, high level persistence
of gene-marked cells. Fractions of circulating gene-marked CD4+ and CD8+ T
cells ranged from 103 to >104 copies/106 PBMC, increased with time in some
patients, and persisted for 100 days. No treatment-limiting side effects related to

the cells were observed.
Conclusions: Adoptive transfer of genetically engineered, HIV-1-specific T
cells was safe. Compared to gene-modified CD8+ T cells alone, CD4+ and CD8+
T cells given together resulted in increased cell survival in the circulation and
provided preliminary evidence of in vivo proliferation of the engineered cells.

I42323 ACTG 285: G-CSF (Filgrastim) for mobilization of CD34+
cells from the bone marrow of HIV-1 infected persons
Robert Schooley1, J. Mladenovil1, T. Campbell1, R. Pomerantz2, S. Miles3,
R. Wong4, A. Landay5. Univerity of Colorado Health Sciences, 4200-E 9th Ave.
Denver CO 80262; 2Jefferson Medical College, Philadelphia PA; 3UCLA, Los
Angeles CA; 4Angen, Thousand Oaks CA; 5Rush Medical College, Chicago IL,
USA
To study the safety and activity of G-CSF in the mobilization of CD34+ stem cells
from HIV-1 infected persons at various stages of HIV-1 disease.
Design: Prospective, stratified, open label
Methods: 18 HIV-1 infected individuals and 6 HIV-1 uninfected control donors
were administered G-CSF (Filgrastim [Amgen]) at a dose of 10/lg/kg/day for seven
days. HIV-1 infected study participants were stratified into cohorts by CD4 cells
at screening evaluation (Cohort I: >500 CD4 cells/mm3, Cohort II: 200-500 CD4
cells/mm3, and Cohort III: <200 CD4 cells mm3). Leukapheresis was undertaken
on days 4 and 5. Lymphocyte phenotypic and functional analysis and plasma
HIV-1 RNA analyses were performed during and following G-CSF administration.
CD34+ cells were separated from leukapheresis product on Multenyi columns.
Results: G-CSF administration and leukapheresis were well tolerated. Peripheral blood CD34+ cells rose with G-CSF administration in each treatment group.
G-CSF was more effective in mobilizing CD34+ cells in uninfected individuals and
in cohort I participants.
CD34+ cells/mm3 in peripheral blood by study day

Cohort
Uninfected
-500
200-500
S200

0 3 4 5
2.16 100 179 133
3 99 168 87
0.66 34 34 57
0.67 18 34 38

6
128
98
42
32

7
104
96
23
23

10
27
11
3
10

Despite less increase in CD34+ cells following G-CSF administration in more
advanced cohorts, CD34+ cells equal plating efficiencies to those obtained earlier
in disease.
Conclusions: G-CSF safely mobilizes CD34+ cells across a broad spectrum
of HIV-1 infection. The lower mobilization efficiency in later stages of illness has
potential implications for genetherapy studies in this population and raises issues
related to marrow reserve in more advanced disease.
42324 Chemokine levels modulated in vivo by DNA vaccines
David Weiner1, Ken Ugen2, K.E. Ugen2, J. Kim1, R. Ciccarelli3, S. Nylan2,
J. Boyer1. 1422 Curie Blvd, Rm 505 Univ Pennsylvania, Philadelphia PA 19104;
2USF College of Med, Tampa Fl; 3Apollon, Malvern PA, USA
Objectives: Measure effects of HIV-1 DNA vaccines on cell produced, and
sera/plasma levels of chemokines in rodents and small primates (macaques)
and HIV-1 infected chimpanzees. Several chemokines have been identified as
possessing anti-HIV-1 activity and methods, in particular vaccination, to increase
their in vivo levels may have both therapeutic as well as prophylactic importance.
Methods: Concentrations of MIP 1 alpha, RANTES and MIP 1 beta were
measured in lymphocytes from immunized mice and in macaque monkeys that
had been vaccinated with env and gag/pol expressing constructs. Measurements
were made by competitive and sandwich based ELISA kits and measured total
(bound + free) concentrations. In addition, measurements were made in HIV-1
(IIIB) infected chimpanzees before and after vaccination with the env (MN) and
gag/pol expressing constructs. This model would allow correlations between vaccine induced immune responses, increases in chemokine levels and viral loads
to be made. These analyses would provide the measurement of a potentially
important vaccine induced parameter.
Results: We observed that DNA vaccines modulated Beta chemokine production significantly in all three animal species examined. Mouse lymphocytes
collected from immunized animals exhibited increased production of MIP-1 alpha,
MIP-1Beta and Rantes. These results were coincident with other immunological
changes including induction of CTL responses. In macaques vaccination with env
and gag/pol expressing constructs results in at least 2 fold increases in the sera
concentrations of the beta chemokines MIP 1 alpha and RANTES in plasma. In
addition, vaccination of HIV-1 infected chimpanzees with the env and gag/pol
constructs resulted in 3-8 fold increases in the sera concentrations of MIP 1
alpha. Importantly, these increases in MIP 1 alpha concentrations were correlated
with the induction of other immune responses and a decrease in viral load.
Conclusions: DNA vaccines for HIV-1 may be a important tool to modulate in
vivo levels of beta chemokines. The role of such modulation should be examined
with regards to vaccine and immune therapy production.
|423251 HIV risk assessment outcome in a phase III trial of
buprenorphine-naloxone opiate dependence
T. Peter Bridge1, P. Fudala2, S. Herbert1, K. Jones3, W. Williford3. The
Buprenorphine Study Group; 'National Institute on Drug Abuse 11A-55 5600
Fisher Lane Rockville MD 20857; 2University Pennsylvania, Philadelphia; 3VA
Cooperation Studies Program, Perry Point, MD, USA
Background: To assess change in HIV risk behaviors in participants in a Phase
III office based clinical trial of buprenorphine naloxone for opiate dependence.
Methods: A 4 week placebo controlled, double blind, random assignment, 3
arm study assessed the efficacy and safety of buprenorphine-naloxone, buprenor