Abstracts Vol. 1 [International Conference on AIDS (11th: 1996: Vancouver, Canada)]

Tuesday, July 9, 1996

Tu.A.27 I - Tu.A.280

Tu.A.27 I
ANTIVIRAL EFFECT FROM THE CD28 COSTIMULATORY RECEPTOR MEDIATES EX
VIVO CD4+ T CELL EXPANSION FROM PATIENT WITH HIV-I INFECTION
St Louis, Daniel C', Levine B**, Mosca J*, Riley J**, Carroll R*, Lin J-T*,Vahey M**,
Jagodzinski L*,Wagner K*, Mayers D**, Burke D**,Weislow O**, June C**, *Henry M.
Jackson Foundation, Rockville, MD, USA; **Military Medical Consortium for Applied
Retroviral Research, Rockville, MD, USA
Human immunodeficiency virus type I (HIV- I) infection is associated with a progressive
decline in CD4+ lymphocytes. Because stimulation of CD4+ lymphocytes leads to activation of HIV- I replication, viral spread and cell death, adoptive CD4+ cell therapeutic strategies have not been possible.We report here that CD28 receptor costimulation can lead to
polyclonal expansion of CD4+ cell from HIV-infected donors during cell culture. Activated
cells secreted predominately cytokines associated with T helper type I function. HIV- I specific expression and proviral DNA load declined during culture. Surprisingly the addition of
antiretroviral agents to cell cultures was not required. Moreover, CD28 stimulation rendered
CD4+ cell from uninfected donors highly resistant to HIV- I infection.The mechanism
responsible for the anti-HIV effect was related to the mode ofT cell activation by antiCD28.While CD4+ cells stimulated with immobilized anti-CD28 were resistant to HIV
infection, cells stimulated with soluble anti-CD28 were highly susceptible to HIV infection.
The CD28-mediated antiviral effect was early in the viral life cycle, prior to HIV- I DNA
integration. In contrast, CD28 costimulation renders CD4+ lymphocytes highly permissive
to retroviral vector transduction.The transduced lymphocytes can be enriched to purify in
culture, and greater than five logs of cell expansion can be achieved.These data may facilitate immune reconstitution and gene therapy approaches in persons with HIV infection.
Dan St. Louis, 1 600 E. Gude Dr., Rockville, Maryland, 20850, U.S.A. phone: [phone],
fax: [phone], email: dstlouis(lcpasteur.hjforg
Tu.A.272
INTERLEUKIN-13 RECEPTOR:A NEW TARGET FOR A PSEUDOMONAS EXOTOXIN
BASED CHIMERIC PROTEIN ON AIDS-ASSOCIATED KAPOSI'S SARCOMA CELLS
Husain SR*, Obiri N*, Gill P**, Pastan I t, Debinski W t, Puri RK*. *Food and Drug
Administration, Center for Biologics Evaluation and Research, Bethesda, MD; **University of
Southern California, Los Angeles, CA; (National Cancer Institute, Bethesda, MD; (Milton S.
Hershey Medical Center Hershey PA, USA
Objectives: To identify novel target on AIDS-Kaposi's sarcoma-derived (AIDS-KS) cells and to
determine if these cells are suitable target for a novel recombinant chimeric protein composed of interleukin- 13 (IL- I 3) and truncated Pseudomonas exotoxin (IL I 3-PE38QQR).
Methods: The expression of IL- 13 receptor (IL- I 3R) on six AIDS-KS cell cultures was determined by binding studies.The structure of IL- I 3R and its interaction with related cytokine,
IL-4, was investigated by affinity cross-linking.The cytotoxic activity of IL 13-PE38QQR on
AIDS-KS was evaluated by protein synthesis inhibition assay
Results: All six AIDS-KS cell cultures expressed large numbers (-3,000-15,000 sites/cell) of
high affinity (Kd= I 24 to 972 pM) IL- I 3R. Human endothelial (HUVEC) and fibroblast
BUD-8) cell lines expressed low numbers or no IL- I 3R. IL-13 competed efficiently for
251-IL-13 binding on AIDS-KS cells while IL-4 showed little competition. Crosslinking studies revealed that 1251-IL- 13 crosslinked to one major protein of -65-70 kDa and this was
abolished by excess IL- I 3 and partially by excess IL-4 in KS248 and NCB-59 AIDS-KS cell
cultures. NCB-59, KS248 and KS220B KS cells were highly sensitive to the cytotoxic effect
of IL 13-PE38QQR.The 50% inhibition in protein synthesis (IC50) in 6 AIDS-KS cultures
was achieved at 2.5 to 263 ng/ml concentration of the chimeric toxin.The cytotoxic activity
of IL 13-PE38QQR was completely blocked by an excess of IL-1I3 but not IL-4 indicating
that IL- I 3R on AIDS-KS cells is distinct from IL-4R.
Conclusions: IL-13 receptor on AIDS-KS cells represent a novel plasma membrane protein(s) that could be utilized for diagnosis and/or targeting with cytotoxic agents, such as
Pseudomonas exotoxin. Additional studies are warr-anted to investigate potential targeting
of IL- I 3R in AIDS-KS in vivi.
SR Husain, NIH Bldg 29B,Rm 2E08,8800 Rockville Pike, Bethesda, MD 20892 USA
Tel: [phone] Fax [phone] email: [email protected]. GOV
Tu.A.273
SPECIFIC T-CELL RESPONSES IN HIV-I INFECTED PATIENTS IMMUNIZED WITH A
RECOMBINANT HIV-I GPI6OVACCINE
Ann-Charlotte Leandersson, G. Bratt**, M. Fredriksson,. Gilljam, J. Hinkula*, S. Nordlund, E.
Sandstrom**, B.Wahren. Karolinska Institute*, Swedish Institute for Infectious Disease
Control and South hospital**, Stockholm, Sweden
Objective: To study the specific T-cell responses in HIV- I infected individuals immunized
with rgp I160 formulated in AIPO4 as an adjuvant. HIV- I infected individuals have a very low
or absent T-cell response to HIV and other antigens.
Methods: The phase 1/11 study includes 40 patients with initial CD4+ T-cell counts above
400xIO6 cells/L.The patients have been repeatedly immunized with rgp 160 i.m.The
patients were randomized for additional treatment with Zidovudine (AZT) or placebo during the first six months.The patients have been monitored for more than 45 months. In
vitro T-cell proliferation assays with the specific HIV antigen rgp I60, the peptide Lp2 and
the recall antigens Tetanus, Influensa and Cytomegalovirus has been performed.
Results: A comparison of the T-cell responses between the group which received both rgp
160 and AZT initially and the group which received only rgp 160 showed improved T-cell
responses to HIV antigens and also to other antigens in both groups. gp I 60 vaccination
only gave a prolonged specific antigen activation while addition of AZT also improved the
CD4 trends. All 40 individuals responded to the rgp I60 in the T-cell proliferation assay.
Conclusions: Immunization with a rgp I 60 vaccine stabilizes the CD4 values and gives a
strong specific T-cell response in asymptomatic HIV-carriers. HIV-infected individuals immunized with rgp I 60 improved their capacity to respond immunologically to HIV antigens and
to several recall antigens.
Ann-Charlotte Leandersson, Swedish Institute for Infectious Disease Control, Dept. of
Virology, 1052 I Stockholm, Sweden. Phone No.: 46-8-7351I085, fax no 46-B-735 1080

Tu.A.274
ACTIVE IMMUNIZATION OF PATIENTS WITH HIV INFECTION:A CONTROLLED
STUDY OF THE EFFECT OFVAXSYN ON PROGRESSION OF IMMUNE DEFICIENCY
Tsoukas, Chris M, Raboud J, Schlech WThomas R, Fong I, Rachlis A, Gill J. Montaner J, Lee 5,
Freedman J, Poon M-C, Lafreniere R, Cassol S, Djurdjev O. Smith G. The Canadian HIV
Trials Network, Canada, MicroGeneys Inc., Meriden, USA
Objective: To describe the effect of recombinant HIV envelope precursor protein VaxSyn
(rgp I 60) on the course of HIV disease during a three year controlled study of HIV infected asymptomatic individuals.
Methods: 280 patients with CD4 counts> 500 cells/mm3 were enrolled in a double blinded, randomised, controlled, multicentre studyThey received 320pg of rgp 160 or placebo
intramuscularly on days 0, 30, 60, 90, I180 and every I120 days thereafter At two years, those
on placebo were treated with rgp 160 on the same dose and injection schedule as those on
the initial active treatment arm. Hematologic and biochemical tests, cellular and humoral
immune responses, as well as HIV viral assessments (on a subset of atients) were carried out.
Results: At enrollment, the median CD4 count was 662 cells/mm (range 474- I 638) all
patients were asymptomatic, 7 1% were in CDC Class II and 29% in CDC Class III. 23 I
(83%) of the patients completed 2 years of follow-up; 186 (67%) completed all 3 years.The
mean declines in CD4 counts at 2 years of follow-up were 155 and III cells/mm in the
VaxSyn and placebo groups respectively (p=.08).The annual rates of decline in CD4 counts
in the VaxSyn and placebo groups were 69 cells/mm3 and 72 cells/mm3, respectively
(p=.30). Among the patients on the placebo arm, the change in rate of decline in CD4
counts from the placebo phase to the active drug phase was 15 cells/mm3 (90% CI=(416,263)).There was no significant difference in rates of change over time (p=.22). Only 12
AIDS-defining events were observed during the study period (5 on the VaxSyn arm and 7
on the placebo arm). One of the seven patients in the placebo group with an ADI died. An
additional patient in the VaxSyn group died.
Conclusion: VaxSyn was well tolerated and free of significant toxicity Patients treated with
rgp 160 had similar declines in CD4 counts during the study period as patients on placebo.
Patients randomized to placebo for the first phase of the study had similar declines on the
placebo and active drug phases of the study
Dr ChrisTsoukas, 1650 Cedar Ave. Room AS.140, Montreal, Quebec, Canada H3G I A4.
Telephone: [phone] Fax: [phone]
Tu.A.275
RESULTS OF A PHASE II DOUBLE-BLINDED, MULTICENTER, PLACEBO
CONTROLLED HIV THERAPEUTIC VACCINE TRIAL
Birx, Deborah L, I Davis C,2 Ruiz N,3 Tamont E,4 Tacket C,4 Poretz D,5 Yanco B,6 Henry
D, Pierce PF, KerkeringT,9 Gordin FI0, Thompson M, I Luskin-Hawk R, 1Yarrish R,1
Holloway W,14 Deyton L,15 Robb M,1 Sitz K,1 Kim j,16 Loomis-Price L,3 Kim 5,3 Michael
N, I Burke DS, I Redfield RR.16 IWRAIR; 2Dept. of the Army; 3HM.JF; 4U Maryland,
Baltimore; 51DP Virginia; 61DRI, Florida; 7Graduate Hospital, Philadelphia; 8Georgetown
UMC; 9Richmond AIDS Consortium; 10Washington VA; I I ARCA Atlanta; I 2AIDS
Research Alliance, Illinois; I 3St.Vincent's Hospital, NewYork; I14Delaware CPCRA; I 5NIH;
161HV, Maryland
The Department of Defense (DoD), collaborating with the National Institutes of Health
(NIH) and private infectious disease physicians, began a phase II, randomized double-blind,
placebo controlled, multi-center study of recombinant gp I 60, formulated by MicroGeneSys,
Inc., in 1990.
Objectives: The objectives of the study were to determine safety immunogenicity, and clinical efficacy of repeated injections of rgp 160 (MGS) over three to five years.
Methods: 608 patients were enrolled, each with early stage HIV infection (asymptomatic,
CD4>400) and no antiretroviral therapy Patients were randomized; half receive rgp 160
injections and half received placebo (alum adjuvant) injections. following the initial injection
series, patients received injections every two months. for the duration of the study The study
was completed December 1995, and results were presented to the DSMB in April 1996.
Results: Patients were followed a range of 34-62 months. Of the 608 volunteers enrolled,
483 completed the trial. 17% were lost to follow-up; 104 due to discontinuation and 2 I to
death. There were a total of 159 primary endpoints reached. 128 volunteers reached a
50% decline in CD4 from baseline and 109 reached a disease progression endpoint
(defined as progression to Walter Reed Stage 4, 5, or 6).
Conclusions: I) adequate power was achieved for determination of efficacy; 2) small, transient differences in CD4 parameters between vaccine and placebo groups were identified;
3) there was no evidence of these small differences in CD4 parameters affecting disease
progression; therefore, there was no evidence of clinical efficacy.
DL Birx, I 3 Taft Court, Suite 200, Rockville MD, 20850 USA Tel: [phone]
Fax: [phone] E-mail: dbir([email protected]
Tu.A.280
PROSPECTIVE FOLLOW-UP STUDIES OF HIV-SPECIFIC CYTOTOXIC T
LYMPHOCYTES (CTL IN A FRENCH COHORT OF I50 PATIENTS: IMMUNOCO
Autran 8.1, E. Gomard,Y Rivier3, H. Agut4, J.M. Bouley, C. Katlama5. the IMMUNOCO
study group. I Immunology CNRS625, 2U. INSERM I 52, 3CNRS II 57, 4Virology and 5Dpt
Mal. Inf, H~p. Pitie Paris, France.
Objectives: to evaluate the precursor and memory CTLs directed against conserved epitopes from HIV- I, their evolution with disease progression, in relationship to immune, virological and clinical parameters.
Methods: 138 HIV I infected stage I1-111 patients with CD4 counts >400 (groupA:67 pts),
200-400 (groupB:65pts), <200/mm3 (groupC: I Ipts) enrolled in I99t, subdivided in progressors and non progressors on the CD4 counts evolution. HIV-specific CTL were studied
once a year using standardized assays: in-vitro restimulation of CTL, EBV target cells + rec.
vacc. virus for the whole and truncated env, gag, pol, nef, rev, tat and vif genes from the HIVI-LAI sequences.
Results: we observed: I) a high conservation of the CTL epitopes with positivity for I HIVI -LAI protein in 87% or for 3 proteins in 60% patients whatever the group 2) a stability of
the antigenic profile recognized by CTL at the Ist year in the 3 groups: 70-80% CTL against
gag, pol, 50%: env, 40-50%: nef 5-20%: tat, rev, vif;3) a slow time course decrease of CTL in
transversal and longitudinal studies of 60 individuals tested over 3 years, with 77%, 67% and

\O
o
crO
C)
0
0
0)
U
0)
N
0l)
U
nC
0
no
C
0
a)
r
N

222