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

XIV International AIDS Conference

Abstracts ThOrA1l380-ThOrA1l384 349

ThOrA1 380 The majority of HIV-1 positive cells in vivo are
multiply infected with divergent viruses
culminating in rampant recombination
A. MeVerhans', A. Jung', R. Maier', V. Jung1, U. Fischer', E. Meese',
G. Bocharov2, J.R Vartanian3, S. Wain-Hobson3. 1University of the Saarland,
Department Virology, Homburg, Germany; 2Institute of Numerical Mathematics,
Moscow, Russian Federation; 3lnstitute Pasteur, Paris, France
Background: From a posterori analyses of genetic variation, recombination can
only be identified when the parental genomes are distinct. For viruses like HIV-1,
this requires the producer cell to be infected by more than one virus, something
that has not been readily forthcoming in vivo.
Methods: Fluorescent in situ hybridisation has been used to identify proviruses
in splenocytes from two HIV-1 patients. Individual cells were laser microdissected
and the HIV genomes were amplified by PCR. Amplified DNA of the hypervariable
V1V2 regions of Env was cloned and several clones were sequenced.
Results: More than 75% of infected splenocytes harboured two or more
proviruses, range 1-8, with a mean of -3-4 per cell. Extrapolation of the frequency
distribution of cellular proviral copy number indicated an upper limit of ~14-16
copies/cell. The distributions were remarkably similar for the two patients despite
different clinical and virological settings. Sequencing of amplified HIV DNA from
individual cells showed an extraordinary degree of diversity - up to 29% amino
acid difference. Furthermore numerous recombinants were evident.
Conclusions: Given the dynamics of HIV-1 turnover in vivo and a recombination
rate of -3 cross-overs per cycle, genomes from a fifteen year old infection may
have undergone as many cross-overs as bases in the genome. Recombination
profoundly influences HIV evolution and presents a huge challenge to its analysis.
Presenting author: Andreas Meyerhans, Department Virology, Building 47, University of the Saarland, 66421 Homburg, Germany, Tel.: [phone], Fax:
[phone], E-mail: [email protected]
ThOrAl 381 HIV-1 super-infection: AE subtype supplanted by B
subtype
S. Jost', M.C. Bernard', L. Kaiser', S. Yerly', B. Hirschell, L. Goh2, L. Perrin'.
'Division of Infectious diseases, University of Geneva, Laboratoire Central de
Virologie, H6pital Cantonal universitaire de Geneve, Geneve 4, Switzerland;
2GlaxoSmithKline, London, United Kingdom
Background: New HIV-1 circulating recombinant forms are increasingly reported.
This suggest that co-infection occurs in vivo.
Case history: A 38 year-old male with an acute retroviral syndrome (ARS) following previous multiple unprotected sexual contacts with male partners was enrolled in the Quest trial (AZT, 3TC, Abacavir, Amprenavir for 25 months, with from
19 to 25 months, vaccination by Alvac vCP 1452 and stop of all treatment at
month 25). Viremia declined from >106 HIV-1 RNA copies/ml (c/mL) and remained <200 c/mL while on HAART One months after treatment interruption,
viremia rebounded to 80'000 c/mL then declined to 20'000 c/mi and raised again,
two weeks later, at 200'000 c/ml (second rebound), to finally fluctuate between
200'000-400'000 c/mL for 5 months before HAART re-initiation.
Methods and Results: Protease (Pr), reverse transcriptase (RT) gag and C2V3
gene sequencing documented an initial infection by subtype AE during the ARS
whereas subtype B rapidly replaced AE at the time of the second rebound. To discriminate between co-infection and super-infection we set up a subtype specific
PCR (end Pr-proximal third of RT) using subtype specific primers for AE and B
designed according to patient's sequences. The subtype specific PCR confirmed
1/the absence of B subtype in both plasma and proviral DNA before the second
viremia rebound 2/the emergence, during the second rebound and later on of B
subtype as the majority subtype in both DNA and plasma. The C2V3 sequences
of the B subtype was related to B Brazilian strains. This correlates with a Brazilian trip of the patient with several unprotected sexual contacts 3 weeks before
B emergence. In in vitro cultures B subtype primary isolate had a much higher
replicative capacity than AE subtype.
Conclusions: This is the first documented case of HIV-1 superinfection. Superinfection has implications for the ever increasing HIV-1 genetic diversity, public
health and vaccines development.
Presenting author: stephanie jost, laboratoire central de virologie, h6pital cantonal universitaire de geneve, 24, rue micheli-du crest, ch-1211 geneve 4,
Switzerland, Tel.: [phone], Fax: [phone], E-mail: stephaniejost
@ hotmail.com
ThOrA 382 Quantitation of HIV-1 DNA forms with the second
template switch (HIV-1 STS DNA) in peripheral
blood predicts disease progression in HIV-1
infection independently of plasma RNA load
L.G. Kostrikis', G. Touloumi', R. Karanicolas2, N. Pantazis',

C. Anastassopoulou', A. Karafoulidou3, J. Goedert4, A. Hatzakis'. 'Athens
University Medical School, University of Athens Medical School, Department of
Hygiene and Epidemiology Mikras Asias 75, Athens 11527, Greece; 2Columbia
University College of Physicians and Surgeons, New York, United States;
3Hemophilia Center of Laikon Hospital, Athens, Greece; 4 Viral Epidemiology
Branch of National Cancer Institute, Rockville, United States
Background: A number of studies have identified several forms of HIV-1 DNA

in peripheral-blood T-cells and lymph nodes in untreated HIV-1-infected individuals and in patients whose plasma HIV-1 RNA load is suppressed by long-term
potent antiretroviral therapy. However, it remains to be established whether the
concentration of HIV-1 DNA in cells has any implications in the progression of
HIV-1 disease in the absence of highly effective antiretroviral therapy.
Methods: We measured the concentration of HIV-1 DNA forms, which have undergone the second template switch (HIV-1 STS DNA) in PBMC samples with
real time PCR and molecular beacons in 130 patients with hemophilia in the Multicenter Hemophilia Cohort Study We assessed the influence of baseline HIV-1
STS DNA levels on the progression of HIV-1 disease by Kaplan-Meier and Cox's
regression analysis.
Results: Among the patients who progressed to AIDS, the median (IQR) levels
of STS HIV-1 DNA in PBMC, were significantly higher compared to those who remained AIDS-free during the 16 years of follow-up [1,017 (235 to 6,059) and 286
(31 to 732) copies per million PBMC respectively; p<0.0001]. The progression
rates of death and development of AIDS varied significantly (log-rank p<0.001)
by quartile distribution of HIV-1 STS DNA levels. By adjusting for age at seroconversion, baseline CD4+ T-cell counts, plasma viral load and T cell receptor
excision circles (TREC) the relative hazard (RH) (95% CI) of death and AIDS
was significantly increased with higher HIV-1 STS DNA levels [adjusted RH=1.84
(1.30 to 2.59) and 2.62 (1.75 to 3.93) per tenfold per million PBMC increase,
respectively].
Conclusions: Our findings show that the concentration of HIV-1 STS DNA in
PBMC had an independent strong effect on the clinical outcome of HIV-1 disease and it may have important implications on the virological response to highly
effective antiretroviral therapy
Presenting author: Leondios Kostrikis, University of Athens Medical School, Department of Hygiene and Epidemiology, Mikras Asias 75, Athens 11527, Greece,
Tel.: [phone], Fax: [phone], E-mail: [email protected]
ThOrA1l383 Association of human leukocyte antigens (HLAs)
with mother-to-child HIV-1 transmission and HIV-1
specific CD8 T-lymphocyte responses
C. Farquhar', S. Rowland-Jones2, D. Mbori-Ngacha3, J. Oyugi3, B. Lohman3,
RP. Otieno3, J. Ochieng3, G. John-Stewart'. 'University of Washington, 325 Ninth
Avenue, IARTP Box 359909, Seattle, WA, 98104, United States; 2Oxford
University, Oxford, United Kingdom; 3University of Nairobi, Nairobi, Kenya
Background: HLA class I and II alleles are determinants of HIV-1 specific CD8
and CD4 T-cell responses. Further characterizing HLAs associated with risk of
HIV-1 infection will be important for future epitope-based vaccine development.
Methods: Blood was collected at birth, 1, 3, 6, 9 and 12 months from infants
followed in a Nairobi perinatal HIV-1 study. Molecular HLA typing was performed
using PCR-sequence specific primers and HIV-1 specific CD8 T-cell responses
were evaluated using ELISpot assays.
Results: HLA typing was performed for 259 infants of whom 43 became HIV-1
infected before month 1 (early) and 7 after month 1 (late). The class I allele A2
was associated with decreased risk of early HIV-1 transmission (HR 0.5; 95% CI
0.2-0.9; P=0.03). Restricting the analysis to breastfeeders, early HIV-1 infection
risk was increased for infants with A29 (HR 2.3; 95% CI 1.1-4.9; P=.03) and the
class II alleles, DR3 (HR 1.9; P=.07) and DQ6 (HR1.9; P=.09). Late transmission
risk was also greater in association with certain HLA alleles, specifically A2 (HR
4; P=.07) and DR14 (HR 9; 95% CI 1.1-78; P=.02). Among infants who remained
HIV-1 uninfected, HLAs A3 and A30 increased the likelihood of an infant CD8 Tcell response (P=.007, P=.003 respectively). This was in contrast to A2 and A23
which were associated with not having a CD8 response at age 1 month (P=.07,
P=.02 respectively). Homozygosity at the A, B, or C locus was not associated with
HIV-1 transmission in this cohort.
Conclusion: In this prospective study of class I and II HLAs, we report A29 to
be significantly associated with early perinatal HIV-1 infection and DR14 to be
associated with late breastmilk transmission. To our knowledge this has not been
previously reported. Our data support an association between A2 and decreased
early transmission as well as increased late transmission. Late HIV-1 infection
among infants with A2 may be attributable to a lower prevalence of HIV-1 specific
CD8 T-cell responses.
Presenting author: Carey Farquhar, 325 Ninth Avenue, IARTP Box 359909,
Seattle, WA, 98104, United States, Tel.: [phone], Fax: [phone], Email: [email protected]
ThOrA1384 Ex vivo fitness studies provides evidence for the
natural attenuation of human immunodeficiency
virus type 1 subtype C during the AIDS epidemic
E.J. Arts, S.C. Ball, A. Abraha. Case Western Reserve University, 10900 Euclid
Ave., Div ID, BRB1034, Case Westen Reserve University Cleveland, OH,
44106, United States

Background: HIV-1 evolves and migrates through individual hosts, overcoming
barriers to transmission and avoiding immune responses. How will this continual evolution and expansion within the human population affect HIV-1 virulence?
We have recently shown that ex vivo HIV-1 fitness (or competitive replication efficiency) is a strong correlate of intrapatient disease progression (Quniones et al.,
2000, J. Virol. 74:9222). Current studies suggest a relationship between fitness,
progression, and subtype prevalence. Attenuated replication of subtype C may re