European Journal of Medical Research - Deutsche AIDS ...

114 EUROPEAN JOURNAL OF MEDICAL RESEARCH
June 27, 2007
E. Virologie
E.1 (Vortrag)
More than one interaction: GBV-C clinical isolates
differ in the ability to interfere with entry and post
entry replication steps of HIV
Jung S. 1 , Tenckhoff S. 2 , Tillmann H. 2 , Müller R. 1 ,
Hess G. 3 , Fleckenstein B. 1 , Reil H. 1
1 Universitätsklinikum Erlangen, Virologisches Institut,
Erlangen, Germany, 2 Universität Leipzig, Innere Medizin,
Gastroenterologie, Leipzig, Germany, 3 Roche, Diagnostics,
Mannheim, Germany
Objective: The majority of clinical studies suggest a beneficial
effect of GBV-C long-term viremia for HIV patients. In
vitro studies reveal a direct influence of GBV-C on HIV replication.
Recently we demonstrated that the GBV-C mediated
HIV-inhibitory effect is not restricted to X4- or R5-tropic
HIV isolates nor to different HIV clades. Now, we studied the
HIV inhibitory capacity of different GBV-C isolates and the
mechanism in more detail.
Methods: GBV-C viremia and replication capacity of respective
isolates were monitored by real-time RT-PCR. GBV-C
phenotypes were determined in co-infection experiments. E2
protein fused to the human IgG-Fc was expressed, purified
and used to stimulate cells before HIV infection. A singleround-of-replication
HIV assay was performed to differentiate
between GBV-C mediated inhibition of early and later HIVreplication
steps.
Results: GBV-C isolates differ in the ability to suppress HIV
replication and thus can be classified as HIV inhibitors and
non-inhibitors. The different GBV-C phenotypes could be
confirmed independently in a second laboratory, but do not
correlate with their replication ability in vitro. The majority of
GBV-C isolates leads to suppression of HIV replication independent
of entry. But in contrast, some GBV-C isolates interfere
only with HIV entry and not with later steps. We could
identify the GBV-C E2 protein to be responsible for HIV entry
inhibition, but definitely not for post entry events. Therefore
other probably nonstructural GBV-C proteins interfere
with later HIV replication steps.
Conclusions: Our results reveal that GBV-C mediated HIV
impairment depends on different GBV-C proteins which interfere
with several HIV replication steps. The GBV-C E2
protein interferes exclusively with X4- and R5-HIV entry,
whereas additionally other GBV-C components suppress post
entry events. These findings could be supported by the fact
that several GBV-C isolates differ in the degree of occurrences
of these HIV-inhibitory attributes. The existence of
different HIV inhibitory phenotypes may explain the controversial
epidemiological data on the influence of GBV-C for
HIV progression in vivo. In addition, the identification of the
E2 protein as a HIV entry-inhibitor may lead to new HIV
therapeutics.
E.2 (Vortrag)
HIV cleavage site mutations in patients with
failing protease-inhibitor therapies
Verheyen J. 1 , Litau E. 1 , Schuldenzucker U. 2 , Oette M. 3 ,
Fätkenheuer G. 4 , Rockstroh J. 5 , Stellbrink H.-J. 6 ,
Däumer M. 1 , Hoffmann D. 7 , Pfister H. 1 , Kaiser R. 1
1 University of Cologne, Institute of Virology, Köln, Germany,
2 caesar, Bonn, Germany, 3 University Clinic Düsseldorf, Clinic
for Gastroenterology, Hepatology and infectious Diseases,
Düsseldorf, Germany, 4 University of Cologne, Department of
Internal Medicine 1, Köln, Germany, 5 University of Bonn,
Department of Internal Medicine 1, Bonn, Germany,
6 Grindelpraxis, Hamburg, Germany, 7 University of Duisburg-
Essen, Center for Medical Biotechnology, Essen, Germany
HIV cleavage site (CS) mutations increasingly attract attention
in the analysis Protease-Inhibitor (PI) resistance. More
efficient cleavage of gag precursor proteins enhance replication
under selective pressure of PIs and confer PI resistance.
Although CS mutations could be correlated with different protease
resistance profiles, knowledge about the occurrence of
CS mutations under selective pressure of certain PIs remained
rudimentary.
We analysed HIV of patients (n=195) under failing PI therapies
(APV n=34, IDV n=17, LPV n=71, SQV n=28 or double
PIs n = 22) with detectable viral loads in the pol gene as
well as in the C-terminal gag region. PR/RT genotypes were
interpreted with geno2pheno (www.genafor.org) and CS mutations
were scored in comparison to HxB2. Statistical significance
was determined using Fisher´s exact test (p