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

12th World AIDS Conference

Abstracts 21171-21174 273

in plasma levels and in vitro production of IL-10 and IL-12. We did not observe
significant differences in plasma MIP-la and MIP-1/ levels. In vitro production of
MIP-la, MIP-1/ and RANTES was significantly higher in HIV+ (group A: 4006
~ 798; 12367 ~ 4365; 4045 ~ 416; group B: 2186 ~ 763; 5544 ~ 2564; 2795
~ 312) than in HIV-patients (group C: 216 ~ 54; 2415 ~ 500; 1860 ~ 324) and
RANTES was significantly more produced by group A vs group B (p = 0.026). We
observed a significant reduction of in vitro production of all three chemokines at
week 8 after starting HAART (MIP-la p = 0.01; MIP-1/: p = 0.039; RANTES: p =
0.025) and a trend towards a reduced production continued at week 20. This was
reflected by significantly reduced circulating levels of RANTES at week 8 only.
Conclusions: Advanced HIV disease is not only associated with reduced IL-2
production but also with an enhanced production of /-chemokines. A subset of
residual IL-2 producers during advanced disease shows lower levels of HIV-RNA
and a better immunological response after HAART. HAART reduces production
of /-chemokines. Correlations with HIV-RNA levels will be presented in detail.
Supported by Programma Nazionale di Ricerca sull' AIDS - 1997. Grant N'
40A.0.75
217*/21171 Alteration of intracellular cytokine synthesis in
CD4+ and CD8+ cell subsets during progression of
HIV disease
Eva Barabas, N.K. Nagy, G.C.R. Gonzalez, H.A. Horvath. Natl. Inst. of
Dermato-Venereology Budapest H- 1085 Maria Str. 41, Hungary
Objectives: We investigate 1. the intracellular cytokine synthesis of IFNy (type
1) and IL-4 (type 2) at the single cell level in several stages of HIV infection, and
2. whether dysregulation in cytokine synthesis is a characteristic of the disease
progression?
Study groups: Asymptomatic HIV infected individuals: 1. with CD4 > 500
cell/pl (n = 5), 2. with CD4 < 200 cell///1 (n = 5), 3. Control subjects (n = 5).
Methods: Flow cytometric three-color analysis (Fastimmune Cytokine System,
BD) was used. Peripheral blood mononuclear cells stimulated for 4 hours with
PMA/lonomycin and brefeldin-A was used to interrupt intracellular cytokine transport. Cell surface were stained with CD4/CD8 PerCP for 15 min. After cell membrane permeabilization intracellular staining applied for 30 min with IFNy/FITC
and IL-4/PE. Cells were fixed in 1% paraformaldehide. Intracellular cytokine
production were analyzed by gating on CD4+, CD8+ cell subsets respectively.
Results: 1. After 4-hour stimulation of PBMCs less than 3% of CD4+ and
CD8+ cells were IL-4 positive (type 2) or double positive (type 0) in all groups.
2. In CD4 subsets, 20% of the activated cells in the control and 17.5% and 12%
of the cells, respectively in HIV infected groups showed IFNy production (NS).
3. In CD8 subsets, however, 53% of the control cells showed IFNy synthesis
compared to that of 32% (p = 0.01) and 10.5% (p < 0.001) positivity in HIV
infected groups. Intracellular IFNy production by cells from patients with CD4
count <200//l was significantly decreased (p = 0.005) than in cells from those
with CD4 count >500//1l.
Conclusions: 1. A progression in dysfunction of CD8+ cells during the course
of HIV infection developed as a consequence of the direct or indirect effect of
the virus was found. This was based on the significantly decreased proportion
of CD8+/IFNy-producing cells. 2. Our data demonstrate a deficiency in type 1
cytokine production. A type 2 phenotype swich, however could not be established
after PMA/lonomycm stimulation in our system.
21172 Involvement of chemokine receptors in the induction of
interferon by HIV-1
Maria R. Capobianchi. Institute For Virology Viale Di Porta Tiburtina 28 00182
Rome, Italy
Background: Persistent activation of the interferon (IFN) system underlies progressing HIV infection. HIV, through its external glycoprotein, induces IFN a and
y in normal PBMC, as a consequence of interaction with both CD4 and galactocerebroside. Additionally, chemokine receptors are involved in HIV infection,
mediating virus envelope fusion with the target cells. The study was aimed to
explore the involvement of chemokine receptors in IFN induction by HIV-1.
Methods: Fixed HIV-1-infected cells were used as IFN inducer in normal PBMC
cultures. Newcastle disease virus (NDV) was used as conventional virus inducer
of IFN 0u. Chemokines were used as competitors, and MAbs or polyclonal antibodies were used as inhibitors of membrane interactions involved in IFN induction.
Methabolic inhibitors were used to block specific signal transduction pathways,
either directly or indirectly bound to the chemokine receptor signaling.
Results: The a-chemokine SDF-1!1, known to block the infection of T-tropic
HIV strains due to interaction with the chemokine receptor CXCR4, inhibits IFN
induction by HIV-1 IIIB (a T-tropic strain). On the contrary, the /-chemokines
RANTES, MIP1-a and -/t, recognizing CCR5, necessary for the infection by
monocytotropic HIV, are virtually ineffective in the IFN induction by HIV-1 IIIB.
Furthermore, the MAb 12G5, and polyclonal antibodies, both recognizing CXCR4,
dose-dependently inhibit IFN induction by HIV IIIB, and not by NDV.
The inhibitor of the protein-tyrosin kinase pathway HA, but not PTX, i.e. an in
hibitor of trimeric G-protein activation, inhibits IFN induction by HIV-infected cells.
Furthermore, both the cycloxygenase inhibitor Indo-M, and the lipoxygenase inhibitor NDGA, involved in the arachidonate methabolism, are virtually ineffective
in IFN induction by HIV.
Conclusions: These results suggest that HIV-1 induces IFN production through
unconventional pathways. In fact, the interaction of gp120 with the appropriate
chemokine receptor is required, besides CD4 binding, in order to obtain efficient

IFN induction by HIV. Furthermore, chemokine receptor driven signal transduction pathway, such as protein-tyrosine kinase activation, seems to be required,
while trimeric G-protein activation and arachidonate methabolism seem not to be
involved.
21173 1 Increased plasma levels of soluble adhesion molecules
during primary HIV-1 infection. Relationship with HIV-1
RNA, TNF-related molecules and clinical outcome
Wilma Barcellini1, L. La Maestra1, G. Clerici1, P. Rizzardi3, A. Lazzarin2.
1Division of Hemathology, Granelli Ospedale Maggoire, V.F Sforza 35, 20122
Milano; 2Malattie Infettive, Milan, Italy; 3CHUV, Laussane, Switzerland
Objective: to investigate plasma levels of soluble forms of endothelial leukocyte
adhesion molecule-1 (sELAM-1), vascular cell adhesion molecule 1 (sVCAM-1)
and intracellular adhesion molecule 1 (slCAM-1) in patients with primary HIV-1
infection (PHI) followed longitudinally, and correlate these markers with plasma
levels of TNF-u, sTNF-receptor (R)-l, sTNFR-Il, sCD30, sCD8, IL-6 and slL-6R,
along with CD4+ and CD8+ T-cell counts, plasma HIV RNA and clinical outcome.
Design and Methods: 26 patients with PHI and 23 HIV-1-negative healthy
blood donors were studied. Investigations were performed at enrolment, week
4, 24 and 52. Seroconversion was assessed by anti HIV-1 + 2 antibodies and
Western immunoblot analysis. HIV-1 RNA was quantitated by Amplicor HIV
MonitorTM test. Samples were assayed for cytokines and receptors by enzyme
immunoassays. Outcome was defined as entering clinical CDC category B or C.
Results: Plasma levels of sELAM-1, slCAM-1 and sVCAM-1 were significantly
increased in patients with PHI compared to HIV-negative controls and showed a
decreasing trend over time. Likewise plasma levels of TNF-u, sTNFR-I, sTNFR-ll,
sCD30, sCD8, and slL-6R were significantly increased, whereas plasma levels of
IL-6 were comparable in PHI patients and controls. An overall positive correlation
was found among plasma levels of slCAM-1 and sVCAM-1 and values of plasma
viremia, TNF-u, its soluble receptors, sCD30 and sCD8 at entry and week 4.
During the course of the study, a clinical outcome occurred in 6 of the 26 patients
studied. Increased plasma levels of HIV-RNA, TNF-a, sTNFR-I, sTNFR-II and
sCD30, as well as sELAM-1, slCAM-1 and sVCAM-1 were found in patients who
rapidly progressed compared to non-progressing patients.
Conclusion: increased levels of soluble adhesion molecules correlated with
the degree of immune activation during PHI, possibly mirroring the degree of
extravascular spreading and HIV-syncytia formation, and might represent, together with plasma viremia and activation markers, early predictors of disease
progression.
218*/21174 Differential effects of IL-4 on HIV-1 expression
suggest a role in viral phenotypic switch and
disease progression
George N. Pavlakis', A. Valintin', W. Lu', M. Rosati', R. Schneider', J. Albert2,
A. Karlsson3. 'ABL - Basic Ic Research Program, NCII - CRDC PO Box B, Boyles
Street, BLDG 535 RM 210 Frederick MD 21716, USA; 2Swedish Institute For
Infectious Disease Stockholm Sweden;3 Soders Juk Huset Stockholm, Sweden
Objectives: To study the effects of the cytokine network on HIV expression and
switching.
Design: HIV-1 isolates have been classified as rapid/high or syncytia-inducing
(SI) and slow/low or non-syncytia-inducing (NSI) according to their biological
phenotype. The main coreceptors for NSI and SI virus entry are the chemokine
receptors CCR5 and CXCR4, respectively. NSI viruses are more likely to be
transmitted and are found early after infection in most infected individuals. In
contrast, SI viruses are usually found in the later stages of disease, and their
appearance is associated with increased viral loads and poor prognosis. Although
a switch from NSI to SI has been demonstrated in a majority of BIV-1 infected
individuals, the mechanism regulating this process is poorly understood.
Methods: We measured expression of CCR5 and CXCR4 coreceptor levels
and correlated these levels to virus propagation in primary lymphocytes and attached macrophages, after treatment with several cytokines including IL-2, IlL-4,
IL-5, IL-10 and IL-13 under different conditions. Specific populations of primary
cells were examined after fractionation and by FAX analysis.
Results: We found that IL-4 inhibited infection by NSI HIV-1 by downregulating
the NSI coreceptor CCR5 in primary T-lymphocytes. In contrast, IL-4 increased
the expression of both NSI and SI virus isolates in primary macrophages. In addition, IL-4 activated intracellular expression, in both T-cells and macrophages, of
all HIV-1 isolates via a tat-dependent transcriptional mechanism. The combination
of these effects results in increased propagation of SI and inhibition of NSI HIV-1
primary isolates. Research sponsored by the National Cancer Institute, DHHS,
under contract with ABL.
Conclusion: IL-4 is an important regulator of HIV-1. It is responsible for modulating the levels of critical virus coreceptors and may have a critical role in the
control of viral evolution and in the phenotypic switch from CCR5 to CXCR4-using
virus.

21175 NSI and not SI viruses enhance cell proliferation and
beta-chemokine production
Jay A. Levy, G. Greco, C.E. Mackewicz. UCSF, Dept. Medicine, San Francisco.
CA 94143-1270, USA
Objective: Determine if infection by NSI and SI virus phenotypes of HIV-1 show