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

270 Abstracts 21156-21161

12th World AIDS Conference

21156 Increased susceptibility to HIV-1 infection of peripheral
blood mononuclear cells from chronically immune
activated individuals
Orit Nahor1, Z.V.I. Bentwich2, A. Kalinkovich3, Z. Weisman3, Z. Greenberg4,
J. Nahmias5, A. Panet1. 1Kadish-Luz 2/38 Ramat Sharet, Jerusalem 92960,
Hebrew University Hadassah Medical School, Jerusalem; 2R. Ben-Ari Institute,
Kaplan Medical Center, Rehovot; 3AIDS Center Kaplan Medical Center, Rehovot;
4Ministry of Health, Jerusalem; 5Zevulun Clinic Kupat Holim, Kiriat Mozkin, Israel
Objectives: To compare the susceptibility for HIV-1 infection of PBMC obtained
from Ethiopian immigrants and from non-Ethiopians Israelis, and correlate it with
parasitic infections and immune activation.
Methods: PBMCs were collected from twenty two Ethiopians (Eth) and seven
non-Ethiopians (NEth) HIV-1 seronegative donors and were subjected to HIV-1
infection, with or without prior stimulation with PHA. Kinetics of HIV-1 P24 antigen
were determined in the culture supernatants. In parallel, T cell subsets and several
membrane activation markers were measured by flow cytometry and parasitic
infections were determined by stool examinations.
Results: Analysis of P24 antigen level demonstrated that HIV-1 replicated
efficiently in PBMCs obtained from both: Ethiopians and non-Ethiopians that
were prestimulated with PHA. However, HIV replicated in PHA-unstimulated
PBMCs was demonstrated in all Eth individuals and in one NEth donor. This
hypersensitivity was associated with increased activation of T cells and in the
majority of the cases (16/22) with one or more intestinal parasites. In contrast, all
non-Ethiopians donors did not express any parasitic infection, and the one that
was high immune activated was also susceptible to HIV infection.
Conclusions: PBMCs obtained from Eth are hypersensitive to infection with
the lymphotropic strain of HIV-1. It's probably associated with wide T cell activation
and parasitic infection. The increased susceptibility of PBMC to HIV-1 infection is
likely to enhance the efficiency of infection in vivo and thus may account for the
rapid spread of the epidemiiic in Africa.
21157 Genotypic and biotypic characterization of HIV-1 subtype
E isolated from blood and genital fluid
Ruengpung Sutthent, K. Sumrangsarp, P. Chaisilwatana, A. Roongpisuthipong,
B. Chaiyakul, P. Puthavathana, C. Wasi. Mahidol University, Department of
Microbiology, Siriraj Hospiatal, 2 Prannok Road, Bangkok, Thailand
Objectives: To compare nucleotide sequence and biotype of HIV-1 subtype E
isolated from blood and genital fluid.
Methods: Eight HIV-1 subtype E isolates were collected from blood, semen,
and cervicovaginal fluid of 2 HIV-1 infected Thai couples (M1-F1 and M2-F2) by
coculture method. HIV-1 genotypic characterization were detected by heteroduplex mobility assay and env nucleotide sequence analysis. We used cell free virus
and infected cells from each isolate to infect SupT1, MT2, primary macrophage,
epithelial cell lines: HeLa, ME180, and HT29 separately to determine biotype of
HIV-1.
Results: Cell associated viruses isolated from blood and semen of M1 and
M2 and from blood and cervicovaginal fluids of F1 and F2 were able to multiply
in epithelial cell lines, SupT1, MT2, and primary macrophage with no different in
replication kinetic in each cell. While, cell free virus of subtype E isolated from
cervicovaginal fluid of F1 multiply more efficiently about 200 times in primary
macrophage than those isolated from blood of Fl. Env nucleotide sequence of E
isolated from cervicovaginal fluid of F1 showed an thirty six nucleic acid bases
insertion in V5 region.
Conclusions: HIV-1 subtype E isolated from genital fluid contain infectivity
efficacy in primary macrophage more than one isolated from blood of the same
subject. The insertion in HIV-1 env gene isolated from genital fluid might responsible for the macophage infectivity efficacy. These results suggest that unique
HIV-1 subtype E in genital fluid might be relevant to the efficiency of subtype E in
heterosexual transmission and important for vaccine development.
21158 Relationships between cell tropism spectrum,
cytopathology peculiarities and clinical features for
Russian HIV-1 isolates
Irma B. Sakhuria1, M.Yu. Schelkanov1, E.V. Ivannikov1, V.V. Burunova1,
V.A. Golikov2, T.V. Pavlova1, E.V. Karamov1. 'lvanovsky Institute of Virology,
Gamaley 16, 123098 Moscow; 2Clinical Infectious Hospital N2, Moscow, Russia
Objectives: To investigate Relationships between cell tropism spectrum, cytopathology peculiarities and clinical features for Russian HIV-1 isolates.
Methods: HIV isolation was carried out according to the standard procedure
based on co-cultivation of HIV-infected patient PBMC with blast-stimulated donor
PBMC. To estimate cell tropism a set of HIV-permissive cell lines (H9, MT-4,
CEM, CEM SS, Sup T1, THP1) and blast-stimulated donor PBMC were acutely
infected, and virus-induced cytodestruction, syncytium-/simplast-induced activity
and p24 supernatant concentration were monitored during 24 days with the 4 day
intervals.

Results: Syncytium-inducing (SI) HIV variants lead to the formation of cell
complexes with multiple intercellular junctions whereas simplast-inducing (Sml)
variants - of multinuclear cell complexes with common membrane. Comparative
analysis of the rate and the level of virus reproduction reveals the existence of not
only rapid/high and slow/low variants but also rapid/low, slow/high and a set of
spacing HIV-1 variants. Rapid/high isolates were recognized to be Sml; slow/low

- both SI and Sml; in the consequence rapid/low-spacing-slow/high - only SI, and
monotonic increasing of virus reproduction level was observed.
Conclusion: Expanding of primarily isolate cell tropism spectrum and SI~Sml
transition were demonstrated to be unfavorable prognostic features of the infection development. Referred unfavorability increases in the following consequence: (slow/low, SI)-(slow/high, SI)-(spacing, SI)-(rapid/low, SI)-(slow/low,
Sml)-(rapid/high, SmI). HIV-1 glycoproteins superexpression is suggested to be
one of the possible mechanism of virus-induced cytodestruction.
274*/ 21159 Indirect mechanism of bystander cell death of CD8
T cells induced by CD4 crosslinking (XL) of CD4 T
cells
Savita Pahwa, M. Tateyama, T. McChoskey, S. Than. North Shore University
Hospital - NYU School of Medicine, 350 Community Drive, Manhasset, NY, USA
Objective: CD4XL by HIV envelope protein gp120 is known to prime CD4 cells
to undergo apoptosis following a second activation signal or upon interaction with
accessory cells. HIV disease is associated with increased lymphocyte apoptosis
of CD4 and CD8 T cells. This study investigated whether CD4XL of CD4 cells
could induce apoptosis in CD8 T cells via a mechanism of cytokine secretion.
Methods: CD4XL was performed in peripheral blood T cells from healthy
donors, followed by stimulation with anti-CD3 mAb with or without anti-CD28mAb.
Three color flow cytometry was utilized to study apoptosis in CD8+ and CD8
subsets by Annexin V staining and intracytoplasmic Bcl-2, Bcl-x and cytokines
IFNy and IL-2.
Results: CD4XL followed by signaling through CD3 molecule resulted in apoptosis of CD8+ (39.5 ~ 5.8%) and CD8 (32.7 ~ 5.9%) T cell subsets as compared
to <10% apoptosis in control cultures, and occurred in association with downmodulation of Bcl-x and upregulation of CD95 in both cell populations. Intractoplasmic
IL-2 secretion was <5% in control cultures and was minimally affected by CD4XL
and anti-CD3 treatment whereas IFNy secretion was augmented in both subsets.
Cells undergoing apoptosis were enriched for IFNy secretion. CD4XL followed by
anti-CD3 plus CD28 co-stimulation increased intracytoplasmic IL-2 and rescued
both T cell subsets from apoptosis and prevented Bcl-x downmodulation.
Conclusions: These studies imply that CD4XL via HIV envelope proteins can
prime not only CD4 but also CD8 T cells to undergo activation induced apoptosis; this process is regulated by the balance of intracytoplasmic IL-2 and IFNy,
presumably via regulation of the anti-apoptotic molecule, Bcl-x, which in turn is
upregulated following CD28 co-stimulation. The loss of CD28 in HIV disease is
important in this context.
21160 Glucocorticoid hormone is the major inducer of CD4+ T
cell death in HIV-1-infected subjects: Inhibition by
anti-Fas antibodies and type-1 cytokines IL-2 and IL-12
Thierry Idziorek, E. Baert, E. Herman, J. Dewulf. Insermu U167 Institut
Pasteurde Lille 1, rue du Pr Calmette 59019 Lille Cedex, France
Objectives: To validate the hypothesis that elevated cortisol concentration in
patients' blood plays a major role in CD4+ T cell depletion.
Subjects and Methods: 94 HIV-1-infected subjects (CDC grades A or B), 48
healthy volunteers, as well as 6 HIV-LAI-infected and 6 healthy chimpanzees
were included in this study. CD4+- or CD8+ T cell-enriched subpopulations were
activated or not by various molecules, including anti-CD3 Mabs, PHA, PWM and
dexamethasone, a synthetic homologue of cortisol. After a 24-h culture, cells were
analyzed for apoptosis by flow cytometry using the impermeant DNA-intercalatant
YOPRO-1. In some experiments, protective anti-Fas antibodies, IL-2, IL-4, 11-10
and IL-12 were added and their effect was compared to the same populations
cultured in their absence.
Results: Our results indicate that CD4+ T cell-enriched populations from
HIV-infected subjects possess an abnormal sensitivity to undergo glucocorticoid-induced apoptosis (GIA) as compared to healthy volunteers (net value
15.9% +/- 3.4 versus 8.1 +/- 2.5). This value is 10, 22 and 49% higher than
the ones observed for PWM, PHA and anti-CD3-induced apoptosis, respectively.
This result suggest that GIA could be a predictive marker for AIDS pathogenesis.
In the non-pathogenic lentiviral infection model, no difference in the ability to undergo GIA between infected and non-infected animals was observed, indicating
that GIA observed in humans for CD4+ T cells, but not CD8+ T cells, is specific
for the pathogenesis. Protective anti-Fas Mabs, as well as 11-2 and IL-12 were
able to inhibit CD4+ T cell GIA by, 55, 67 and 72%, respectively, whereas IL-4
augmented and IL-10 demonstrated no effect on GIA.
Conclusions: These data point out the important issue of Fas-dependent GIA
in the process of CD4+ T cell depletion in AIDS pathogenesis. Type 1 cytokines
IL-2 and IL-12 could therefore play a role as adjunct therapy to antiretrovirals.
|21161 Expression of molecules responsible for lymphocyte
activation-induced cell death in primary acute infection
Andrea Cossarizza. Dept. Biomedical Sciences Via Campi 287 41100 Modena,

Italy
Objectives: Peripheral blood lymphocytes (PBL) from patients experiencing an
acute, primary infection have a relevant propensity to spontaneous apoptosis. In
10 of them we have investigated the role and functionality of molecules capable of
inducing cell death (CD95) and of activation markers (CD38 and CD45 isoforms).