Abstract Book Vol. 2 [International Conference on AIDS (14th: 2002: Barcelona, Spain)]

XIV International AIDS Conference

Abstracts ThOrA1l436-ThOrA1l481 351

probenecid potentiated in vitro the anti-HIV activity of AZT and indinavir. These
effects were accentuated when PSC833 and probenecid were combined.
Conclusion: These results showed that 1) the HIV infection by increasing the
ABC transporter expression could favorise the efflux of antiretroviral drugs and
decrease their pharmacological effects, and 2) specific inhibitors of these transporters could reverse these deleterious effects.
Presenting author: sylvie jorajuria, service de neurovirologie, drm/dsv, commissariat a I'energie atomique (cea), 60, 68 avenue de la division leclerc-bp6, 92 265
fontenay-aux-roses cedex, France, Tel.: + 33 1 46 54 87 38, Fax: + 33 1 46 54 77
26, E-mail: [email protected]
ThOrA1 436 Natural killer cells and T cells infected by HIV
contribute to long term viral reservoirs and to
cellular sanctuaries for protease inhibitors
A. Valentin1, R. Yarchoan2, G.N. Pavlakis1. 1NCI-Frederick, Frederick, United
States; 2NCI, Bethesda, United States
Background:We have shown that in addition to T cells, NK cells are persistently
infected by HIV, and they can transmit infectious virus.NK cells are known to have
a highly active P-glycoprotein (P-gp) pump, a member of the ABC family of transporters associated with therapeutic failure and multidrug resistance.Protease inhibitors are known substrates for P-gp.We hypothesized that high P-gp activity in
some HIV-1 infected cells might account for a suboptimal pharmacological effect
of protease inhibitors leading to treatment failure.
Methods:GFP-tagged HIV-1 molecular clones were used to study P-gp activity
in infected primary cells in vitro.We used Rh123 and TMRE, two fluorescent P-gp
pump substrates, to study the P-gp activity in different subsets of primary cells
by flow cytometry.This methodology allowed functional studies of pump activity
combined with the immunophenotyping of different cell subsets.Live infected cells
identified by GFP expression were compared to uninfected cells.
Results:We have identified a population of CD4+CCR5+ primary cells with very
high P-glycoprotein efflux activity.These cells are phenotypically heterogeneous
and were identified as T lymphocytes and NK cells.They were found in both uninfected and HIV-1 infected individuals.Functional studies demonstrated that higher
concentration of protease inhibitors is required to achieve the pharmacological
effects of the drugs in these cells.Monitoring GFP-tagged infected cells demonstrated that very high P-gp activity is present in some cells actively replicating
HIV-1.
Conclusions:Our results suggest the presence of pharmacological cellular sanctuaries resistant to the antiviral effects of protease inhibitors.The presence of
these cells could be responsible for HIV-1 persistence in patients receiving
HAART.New therapeutic interventions to eliminate these cells are required to successfully treat HIV-1 infected patients.
Presenting author: Pavlakis George, National Cancer Institute at Frederick,
1050 Boyles Street, Bldg. 535, Rm. 206, Frederick, Maryland 21702-1201, United
States, Tel.: [phone], Fax: [phone], E-mail: paviakis@ ncifcrf.gov
ThOrA1l479 TREC+ lymphocytes and IL-7 system in
"CD4-exploders", a group of HAART-treated, HIV+
patients with an optimal reconstitution of the CD4+
T cell pool.
C. Mussini1, M. Pinti2, V. Borghi1, M. Nasi2, E. Monterastelli2, L. Troiano2,
L. Moretti2, G. Amorico1, R. Esposito2, A. Cossarizza2. 1Azienda Policlinico,
Modena, Italy; 2Univ. of Modena, Modena, Italy
Among a population of more than 500 HIV-infected patients treated with highly
active antiretroviral therapy (HAART), we found 6 individuals who experienced a
nadir of less than 85 CD4+ cells/lL (range: 11-84), had major opportunistic infections (4 out of 6), started HAART in 1996 or 1997, and showed a rapid and
relevant CD4+ lymphocyte increase, regardless of virological control (actual HIVRNA plasma levels: 870-2140 copies/mL). This increase (in all cases, CD4+ T
cells were >870 cells/lpL), still present after 5 years, was mainly due to the production of virgin T cells (CD45RA+,CD62L+,CD95-). We defined these patients
as "CD4-exploders" and analyzed some crucial characteristics of their immune
system. High levels of lymphocytes possessing the T cell receptor rearrangement
excision circles (TREC, detected by competitive-quantitative PCR) were found
among CD4+ or CD8+ T cells, whose V3 T cell repertoire was normal (by flow
cytometry and CDR3 lenght analysis). However, chest-computed tomography revealed a dramatic depletion of thymic lymphoid tissue. We measured plasma
levels of interleukin (IL)-7 and the expression of IL-7 receptor o chain (IL-7Ri,
analyzed either at the protein or the mRNA level) that were significantly high.
Most CD4+ and CD8+ T cells expressed IL-7R, whose level was similar to that
of healthy donors but markedly higher than those of individuals treated with the
same therapy (but a minor CD4+ increase) or in AIDS patients. As TREC are
present in "recent thymic emigrant" lymphocytes, and are thus related to thymus
functionality, it can be hypothesized that in "CD4-exploders" the reconstitution of

the T cell compartment due to HAART could occur extrathymically, and is in any
case favoured by the upregulation of the IL-7/IL-7R system.
Presenting author: Andrea Cossarizza, via Campi 287, 41100, Modena, Italy,
Tel.: [phone], Fax: [phone], E-mail: [email protected]

ThOrAl480 Reconstitution of autologous isolate neutralizing
antibodies under HAART and emergence of
neutralization escape mutants in vivo
S. Matsushita, T Kimura, F Wang, J. Kim, A. Koito, K. Yoshimura. Center for
AIDS Research, Kumamoto University, Division of Clinical Retrovirology and
Infections diseases, Center for AIDS Research, Kumamoto University 2-2-1
Honjo, Kumamoto 860-0811, JAPAN, Japan
Background: Effects of HAART in chronically infected patients, with regard to
neutralizing antibody (NAb) responses against autologous isolates and a role of
such NAbs in patients during viral rebound are poorly understood.
Methods: We investigated the longitudinal change of NAb response against an
autologous HIV-1 in 19 chronically infected patients on HAART In the course of
the study we experienced three patients who had NAbs to pre-existing autologous
HIV-1 and an episode of viral rebound after a long-term viral suppression. Envelope genes of pre-existing and rebounded viruses were sequenced and examined by phylogenetic analysis. Neutralization-sensitivity was examined by using
envelope-pseudotyping.
Results:Reconstitution of neutralization activities was observed in 3 of 6 patients
with no significant activities at the initiation of HAART. 13 out of 19 patients initially
showed significant activities, but these were relatively weak in many subjects and
most sustained the activities during HAART For the patients with viral rebound,
phylogenetic analysis of env (V1-V4) sequences indicated that rebounded viruses
had evolved from or pre-existed in baseline populations. Rebounded viruses were
found to be significantly resistant to neutralization by autologous antibody in patients, who experienced viral rebound thus indicating that rebounded viruses were
selected by NAbs. The site responsible for conferring neutralization resistance
against autologous antibody was identified in the up-stream C3 region in two out
of three patients.
Conclusions:We obtained evidence for reconstitution of spontaneous neutralization activities in some chronically infected patients. The viral rebound in the
presence of neutralization antibodies is associated with the emergence of the relatively resistant mutants to autologous antibodies. The neutralization resistance
observed in vivo was conferred by C3 changes.
Presenting author: Shuzo Matsushita, Division of Clinical Retrovirology and Infections diseases, Center for AIDS Research, Kumamoto University, 2-2-1 Honjo,
Kumamoto 860-0811, JAPAN, Japan, Tel.: [phone], Fax: [phone], E-mail: [email protected]
ThOrAl 481 Intermittent cycles of IL-2 increase CD4+ T cell
counts but do not enhance antibody responses to
immunization: results of A5046s
H. Valdez', M.M. Lederman', R.B. Pollard2, D. Sahner3, A. Sevin4, E. Chan4
R. Moss5, S. Estep6, L. Fox6, A. Namkung7, R. Mitsuyasu8, A. Landay9,
J.L. Fahey8. I Case Western Reserve Center for AIDS Research, 2061 Cornell,
Rm 401B, Cleveland, OH 44106, United States; 2University of California, Davis,
Sacramento, United States; 3Chiron Corporation, Emeryville, United States;
4Harvard School of Public Health, Boston, United States; 5lmmune Response
Corporation, Carlsbad, United States; 6DAIDS, Bethesda, United States; 7ACTG
Operations Center, Rockville, United States; 8 UCLA, Los Angeles, United
States; 9Rush-Presbyterian-St Lukes, Chicago, United States
Background: IL-2 increases the numbers of CD4+ cells in patients with HIV infection. We wished to ascertain whether increasing CD4+ cell numbers would
improve antibody responses to immunization.
Methods: ACTG 328 compared CD4 changes in patients treated with HAART +/IL-2; to qualify patients had to have CD4+ counts < 350. 38 patients with viral
loads (VL) <2000 c/mL after at least 60 weeks on ACTG 328 received Remune
(inactivated, gp-120 depleted HIV: 3 times 2 months apart) and Tetanus Toxoid
(twice 2 months apart). Hepatitis A (HA) and/or B (HB) unexposed patients received HA (twice 2 months apart) and/or HB vaccines (3 times 2 months apart).
IL-2 administration and immunizations were separated by 4 weeks. IL-2 dose: 4.5
MIU SQ BID for 5 days every 8 weeks.
Results: Patients were on HAART for 98 weeks prior to enrolling in A5046s.
Patients in the IL-2 group (25 of 38) received 10 cycles prior to immunization.
Pre-HAART CD4+ (221 vs. 242) and CD8+ (458 vs. 446) counts were similar;
but at immunization the IL-2 group had higher CD4+ (865 vs. 444, p= 0.02) and
CD8+ (969 vs. 718, p< 0.03) counts. Pre-HAART VL was higher in the IL-2 group
(4.6 vs. 3.7 log10, p=0.06), but was similar at immunization. At week 24, 36%
of patients in each group developed a 4-fold rise in p24 antibodies. Also, 30% of
HAART+IL-2 patients and 40% of HAART alone recipients developed a 4-fold rise
in tetanus antibodies. Compared to HAART + IL-2 recipients, there was a trend
for a greater proportion of HAART alone recipients to develop antibody responses
after HA immunization (88% vs 36%, p=0.06 at week 24) while a similar proportion of patients in each group responded to HB (50% vs. 13%, p=0.25 at week
24).
Conclusions: While intermittent high dose IL-2 increases the number of circulat
ing CD4+ cells, these additional CD4+ cells do not confer an enhanced antibody
response to immunization.
Presenting author: Hernan Valdez, 2061 Cornell, Rm 401B, Cleveland, OH
44106, United States, Tel.: [phone], Fax: [phone], E-mail:
valdez.hernan @ clevelandactu.org