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

12th World AIDS Conference

Abstracts 41205-41209 783

Results: CCBs are shown to influence the HIV adsorption and fusion as well
as the action of virus-specific enzymes. The CCB peptides contain some epitopes
similar to the influenza virus hemagglutinin, the gh-protein of herpes/Epstein -Barr
virus, and to the p17 HIV peptide. Polyfunctional CCB properties are used for the
anti-viral protection of the cell. In a system of MT4/BIII cells carrying the persistent
HIV infection the CCB inhibit the p24 antigen expression and HIV infectivity (by
3-4 Ig ID50). The HIV reproduction was also inhibited (by 2.5-3 Ig ID50) in a
model of acute HIV infection in MT4 cells treated simultaneously with the CCB
preparations and virus suspension.
Conclusion: Bacterial and lymphoid CCBs are potent inhibitors of the HIV
reproduction.
41205 Inhibition of HIV-1 replication by newly developed
polymeric adamantane analogue
Marina Boursteine1, A.V. Serbin2, L.L. Stotskaya3, T.V. Khakhulina4,
A.G. Boukrinskaya4. 18-St Sokolinoy Gory 15 dep 3 "Antivich" Moscow 105275;
2Health Research & Development Foundation Moscow; 3 nstitute of
Petrochemical Synthesis, RAS Moscow; 4D.1. Ivanovsky Institute of Virology,
RAMS Moscow, Russia
Objectives: To study the mechanism of inhibition of the HIV-1 replication by
newly developed adamantane analogue
Methods: The drug was added to HIV-1 infected lymphoblastoid MT-4 cells,
the drug was added with the virus, immediately after virus adsorption and 1 hour
after virus adsorption. The effect of the drug was shown by immunobloting of cell
lysates. The absence of cytotoxic effect was shown by Reed-Muench method for
estimating cytotoxic dose (CTD5o).
Results: When the drug was added with the virus; immediately after virus
adsorption and 1 hour after adsorption the strongly HIV-1 inhibition was shown.
When the drug was added later the inhibition was not shown. The drug does not
impair the virus structure.
Conclusion: The drug does not significantly affect the virus adsorption, mostly
affecting the later stages of infection, probably blocking the virus uncoating and/or
the transport of preintegration complex into the nuclei
41206 Structure/function relationship of trichosanthin (TCS) on
anti-human immunodeficiency virus type 1 activity
Yong Tang Zheng1, B.L. Ben1, H.L. Nie2. 'Kunming Institute of Zoology, The
Academy of Sciences, Kunming, Yunnan 650223; 2Shanghai Institute of Cell
Biology, CAS Shanghai, The People's Republic of China
Objectives: To gain insight into the structure/function relationship of TCS on
anti-HIV activities
Methods: The anti-HIV activities of 5 TCS mutants were examined by the
following measurement: 1) the inhibition of syncytia formation; 2) the protection
of HIV-1 infected cell; 3) inhibition of HIV-1 infected cell fusion in coculture; 4)
reduction of p24 antigen expression and numbers of HIV antigen positive cells in
acutely and chronically infected culture.
Results: TCS (SI = 193) from Trichosanthes kirilowii, TCS genetic mutants S3
(SI = 66.7) and S5 (SI = 23) inhibited syncytia formation induced by HIV-1 IIIB.
Mutants S1, S2 and S6 did not inhibited syncytia formation. All mutants were
unable to block HIV infected cell fusion in coculture, and did not protect HIV-1
infected MT-4 or C8166 cells from dying. S5 markedly reduced both expression
of p24 core protein (EC50, 8.87 pg/ml) and the numbers of HIV antigen positive
cells (EC50, 0.87 pg/ml) in acutely but not chronically HIV-1 infected culture.
S3 showed slight inhibition of expression of p24 antigen and reduction of the
numbers of HIV antigen positive cells in acutely HIV-1 infected culture.
Conclusion: Anti-HIV activity of TCS is associated with ribosome inactivating
activity. C-terminal animo acid sequence of TCS does not or slightly affect the
anti-HIV activity.
41207 Anti-human immunodeficiency virus (HIV) activity, of
NARL-1, an polycassine extracted from a kind of plants,
Indocalamus, in vitro
Yan Jiang1, C.Y. Chen2, Y. Xiao3, S. Cao4, L.J. Pei3, H. Zhang3, Y.M. Shao3.
1100 Yingxin Street Beijing 100052; 2Academy Chinese Science; National AIDS
Reference Lab (NARL), Beijing; 3Peking University Beijing, PR China
Objective: Study on the anti-HIV effect of NARL-1 in vitro.
Methods: MT-4 cells inoculated with 200TCID50 HIV-1 (SF33) were used as
in vitro model to test anti-HIV effects of the NARL-1. After 6 days, cytopathic
effect (CPE), viable cells and p24 antigen in the cultural supernatants were used
as marker to mornitor the virus growth. Viable cells and p24 antigen were measuremented by a automated tetrazolium-based colorimetric assay and a sensitive
ELISA, separately. The supernatants with or without NARL-1 were inoculated to
nomral MT-4 cells for determining infectivity. IC5o was used as the end point for
the effectiveness of the experiments.

Results: It is found that NARL-1 can inhibit virus replication in dose-dependent
matter (IC50 = 80 ug/ml). The inhibition was enhanced by the exsistence time of
drug in culture. Under noncytotoxic concentration, inhibition to viral replication by
NARL-1 was 73.3%, 87.7% and 95.4% in 1 week, 3 week and 4 week culture,
respectively. Infectivity of the supernatant with the presence of NARL-1 was
decreased 1000 times than that of the control. But MT-4 cells pretreated with
NARL-1 not resistant to viral infection.

Conclusions: The NARL-1 showed inhibitory effect to HIV-1 replication in MT-4
cells. Antiviral effect of NARL-1 in peripheral blood mononuclear cell (PBMC) and
it's antiviral mechanism are investigating.
41208 High prevalence of protease resistance mutations in
therapy-naive HIV-1 positive German seroconvertors
irrespective of viral subtype
Ursula Dietrich1, H. Knechten2, H. Jiger3, R. Husak4, H. Ruppach1, H. von
Briesen1. 1 Georg-Speyer-Haus Paul-Ehrlich-Str. 42-44, 60596 Frankfurt;
2Praxiszentrum Blondestr, Achen; 3Kuratorium FOr Immunuschwache,
Mjnchen; 4Universitatsklinik Benjamin Franklin, Berlin, Germany
Objectives: To determine the presence of drug resistance mutations in the HIV-1
genomes derived from recently infected therapy-naive Germans.
Methods: All patients involved in this study were Germans recently infected
with HIV-1 (2 to 14 months prior sample collection). All were therapy-naive. Resistance mutations were determined by direct sequencing of PCR-fragments from
the pol gene, including reverse transcriptase and protease, respectively. Viral
subtypes were determined by V3-based differential serotyping complemented by
direct sequencing of the V3 region.
Results: A total of 43 samples was analyzed so far. Although all patients were
therapy naive at the timepoint of sampling, 17 of 27 samples analyzed contained
resistance mutations for proteas inhibitors, including primary resistance mutations. Resistance mutations for zidovudine were found in 2 drug-naive patients.
1 of the recent infections analyzed were due to non-B HIV-1 subtypes. HIV-1
infections were acquired through different routes including heterosexual and homosexual transmission, injecting drug use and needle stick exposure. Protease
resistance mutations were found independently of viral subtype. The frequency of
these mutations was higher for samples derived from infections which occurred
after introduction of protease inhibitors into the standard combination therapy
regimen, although larger numbers of samples have to be analyzed for statistical
significance.
Conclusions: Protease resistance mutations are highly prevalent among therapy-naive recent HIV-1 infections in Germany. Therapy resistance monitoring
before and during treatment is essential in order to optimize individual therapeutic
treatment.
41209 Rapid phenotypic detection of HIV-1 resistance to
lamivudine (3TC) and nevirapine (NVP) by direct analysis
of plasma reverse transcriptase activity
Walid Heneine1, J.G. Garcia-Lerma1, J.G. Vasquez-Rosales1, H. Havlir D.2,
R.F. Schnazi3, D.D. Richman2, T.M. Folks1. 11600 Clifton Rd, NE, MS-G19,
HIV/Retrovirology Branch, CDC Atlanta, GA 30333; 2VA Medical Center Univ of
California, LA Jolla CA; 3Emory Univ and JA Medical Center Atlanta GA, USA
All present assays currently used for the analysis of phenotypic resistance to
HIV-1 inhibitors are culture-based time consuming. We describe the use of a non
culture-based assay for the rapid analysis of HIV-1 resistance to 3TC and NVP
based on the direct testing of the susceptibility of plasma HIV-1 reverse transcriptase (RT) to inhibition by 3TC-TP or NVP. RT levels in plasma are quantitated by
the ultrasensitive PCR-based Amp-RT assay which uses an ELISA-based non
radioactive oligoprobing system. The level of inhibition of plasma RT by 3TC-TP
(5 uM) or NVP (50 uM) was used to define susceptibility to these drugs. Testing
results are obtained in 1-2 days. The assays detected phenotypic resistance
only in HIV-1 reference viruses containing 3TC- or NVP- resistance mutations,
but not in wild type (WT) or AZT-resistant viruses. To evaluate applicability to
clinical samples, plasma specimens obtained before and after initiation of therapy
with 3TC (n = 30) or NVP (n = 30) were analyzed, and the phenotypic results
were compared to genotypic data obtained by sequencing and/or by a Line Probe
Assay. Of the 30 samples analyzed for 3TC resistance, 12 were found to be sensitive by the Amp-RT assay. Of these, 11 had WT genotypes and 1 had a mixture
of WT and M1841. All 12 represented pretreatment samples. Eighteen samples
showed evidence of phenotypic resistance; all were post-treatment samples obtained after 1-60 weeks of therapy. Of these, 12 had the M184V mutation, 4 had
mixtures of WT and M184V, and 2 were WT. Of 30 plasma specimens collected
longitudinally from 4 patients at initiation of NVP monotherapy, 23 were found to
be sensitive to NVP. All 23 samples were WT and represented pre-therapy or
samples obtained during the first 2 weeks of treatment. Seven specimens showed
evidence of phenotypic resistance and corresponded to samples obtained from
day 7 to day 38 of therapy. All 7 samples had the 181C mutation associated with
NVP resistance.
In contrast to culture-based phenotypic assays, this plasma RT-based phenotypic assay is a rapid and simple method for analyzing phenotypic resistance
to 3TC and NVP, and therefore, provides a feasible tool for surveillance and
clinical monitoring of drug resistance. This testing approach could be expanded
to analysis of resistance to other RT inhibitors.