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Current
HIV Research
ISSN: 1570-162X
Current HIV Research
Volume 6, Number 3, May 2008
Contents
Assays for the Determination of HIV-1 Load in Semen:
A Review of Indications, Methods and Performance In Vitro
Pp. 182-188
Derek J. Chan and Leon McNally
[Abstract]
The Challenge of IL-2 Immunotherapy in HIV Disease: “No
through Road” or Turning Point? Pp. 189-199
Giulia Marchetti, Camilla Tincati, Antonella
d’Arminio Monforte and Andrea Gori
[Abstract]
HIV Nef: Role in Pathogenesis and Viral Fitness Pp.
200-208
Kevin K. Ariën and Bruno Verhasselt
[Abstract]
The Compound 6-Chloro-1,4-Dihydro-4-Oxo-1-(β-D-Ribofuranosyl)
Quinoline-3-Carboxylic Acid Inhibits HIV-1 Replication by
Targeting the Enzyme Reverse Transcriptase Pp. 209-217
Thiago Moreno L. Souza, Claudio Cesar Cirne-Santos,
Diego Q. Rodrigues, Celina M. Abreu, Amílcar Tanuri,
Vitor F. Ferreira, Isakelly Pereira Marques, Maria Cecilia
Bastos Vieira de Souza, Carlos Frederico Leite Fontes, Izabel
Chistina de Palmer Paixão Frugulhetti and
Dumith Chequer Bou-Habib
[Abstract]
Transcytosis-Blocking Abs Elicited by an Oligomeric Immunogen
Based on the Membrane Proximal Region of HIV-1 gp41 Target
Non-Neutralizing Epitopes Pp. 218-229
Nobuyuki Matoba, Tagan A. Griffin, Michele Mittman,
Jeffrey D. Doran, Annette Alfsen, David C. Montefiori, Carl
V. Hanson, Morgane Bomsel and Tsafrir S. Mor
[Abstract]
Suppression of HIV Replication In Vitro by CpG and
CpG Conjugated to the Non Toxic B Subunit of Cholera Toxin
Pp. 230-238
Salma Nowroozalizadeh, Marianne Jansson, Jenni Adamsson,
Marianne Lindblad, Eva-Maria Fenyö, Jan Holmgren and
Ali M. Harandi
[Abstract]
Relative Dominance of Env-gp41-Specific Cytotoxic T Lymphocytes
Responses in HIV-1 Advanced Infection Pp. 239-245
Yan Zhuang, Yongtao Sun, Song Zhai, Dedong Huang,
Shuguang Zhao, Shaoyang Wang, Wenzhen Kang, Xinhong Li, Bruce
D. Walker, Marcus Altfeld and Xu G. Yu
[Abstract]
CADA, a Potential Anti-HIV Microbicide that Specifically Targets
the Cellular CD4 Receptor Pp. 246-256
Kurt Vermeire, Joachim Brouwers, Yven Van Herrewege,
Roger Le Grand, Guido Vanham, Patrick Augustijns, Thomas W.
Bell and Dominique Schols
[Abstract]
Mortality and Morbidity of HIV Infected Patients Receiving
HAART: A Cohort Study Pp. 257-260
George Panos, George Samonis, Vangelis G. Alexiou, Garyfallia
A. Kavarnou, Gerasimos Charatsis and Matthew E. Falagas
[Abstract]
HIV-1 Residual Viremia and Proviral DNA in Patients with Suppressed
Plasma Viral Load (<400 HIV-RNA cp/ml) During Different
Antiretroviral Regimens Pp. 261-266
Emanuele Nicastri, Lucia Palmisano, Loredana
Sarmati, Gabriella D’Ettorre, Saverio Parisi, Mauro
Andreotti, Annarita Buonomini, Franca M. Pirillo, Pasquale
Narciso, Rita Bellagamba, Vincenzo Vullo, Marco Montano, Giovanni
Di Perri and Massimo Andreoni
[Abstract]
Anti-Chlamydophila pneumoniae Antibodies as Associated
Factor for Carotid Atherosclerosis in Patients with AIDS
Pp. 267-271
Verónica Gaona-Flores, Guadalupe García-Elorriaga,
Maricela Valerio Minero, Emma González-Veyrand, Rogelio
Navarrete-Castro, Norma Palacios-Jiménez, Guillermo
Del Rey-Pineda, César González-Bonilla and
Lorenzo Monasta
[Abstract]
Phase 1 Single Dose Studies to Optimize the Pharmacokinetics
of DG17, a Novel HIV-Protease Inhibitor Pro-Drug, Using Sodium
Bicarbonate and Ritonavir Pp. 272-275
Catherine L. Cherry, Jennifer F. Hoy, James S.
Rowe, Henry Krum, John Mills and Sharon R. Lewin
[Abstract]
Abstracts
[Back to top]
Assays for the Determination of HIV-1 Load
in Semen: A Review of Indications, Methods and Performance
In Vitro
Derek J. Chan and Leon McNally
Techniques for the quantification of HIV-1 load in semen
include culture and nucleic acid amplification techniques.
The latter tend to be used in the reproductive, public health
and research settings due to speed, throughput, sensitivity
and capacity to eliminate and control for contamination or
inhibitory substances from semen. Commercially-available assays
such as nucleic acid sequence-based amplification and reverse
transcriptase polymerase chain reaction are equivalent in
yielding more reliable and reproducible results than in-house,
non-commercial assays, and should be used for the determination
of HIV-1 load in semen. Sensitivity is increased when silica
extraction methods are used.
[Back to top]
The Challenge of IL-2 Immunotherapy in HIV Disease:
“No through Road” or Turning Point?
Giulia Marchetti, Camilla Tincati, Antonella
d’Arminio Monforte and Andrea Gori
The perception of HAART failure in achieving broadest
immune reconstitution has further strengthened the rationale
to widely explore new adjuvant immunotherapy. Most work has
been performed on IL-2, given its potential to correct HIV-driven
immune defects, possibly translating in enhanced immune competency.
This is a literature review report reviewing different trials
on IL-2 immunotherapy in HIV/AIDS in the past ten years through
the Cochrane and NIH review database. IL-2 can benefit severely
compromised patients, either HAART-naïve or
lacking HAART-driven immune rescue. Furthermore, by sparing
HAART-related toxicity, IL-2 is indicated within treatment
interruptions or immunization protocols. Important clinical
insights stem from the IL-2-mediated immune reconstitution,
with a rise in long-term peripheral T-cell turnover, survival
and functional markers. Furthermore, IL-2 immunotherapy proved
to interfere with cytokine networks with specific regulatory
functions over T-cell homeostasis and function. Despite the
plethora of immunological findings exploring the intriguing
hypothesis that IL-2 might contribute to amend the skewed
T-cell immunophenotype and cytokine milieu in HIV/AIDS,
major question on the actual clinical impact remain unanswered.
This review is meant to thoroughly explore the possibility
that the immunological advantages described during IL-2 immunotherapy
might translate into actual clinical benefits in the treatment
of HIV/AIDS disease.
[Back to top]
HIV Nef: Role in Pathogenesis and Viral Fitness
Kevin K. Ariën and Bruno Verhasselt
Conserved in all primate lentivirus genomes, Nef promotes
viral replication and infectivity, influences the trafficking
of a large number of surface receptors and interferes with
TCR signalling, consequently modulating T-cell activation.
In vivo observations with Long Term Non-Progressors
harbouring a Nef-defective HIV and vaccination studies with
Nef-deleted SIV in Rhesus macaques have shown a prominent
role for Nef in lentiviral pathogenesis. Here we review the
functions of Nef involved in viral replication and infectivity
and speculate on a possible role for Nef in HIV fitness.
[Back to top]
The Compound 6-Chloro-1,4-Dihydro-4-Oxo-1-(β-D-Ribofuranosyl)
Quinoline-3-Carboxylic Acid Inhibits HIV-1 Replication by
Targeting the Enzyme Reverse Transcriptase
Thiago Moreno L. Souza, Claudio Cesar Cirne-Santos,
Diego Q. Rodrigues, Celina M. Abreu, Amílcar Tanuri,
Vitor F. Ferreira, Isakelly Pereira Marques, Maria Cecilia
Bastos Vieira de Souza, Carlos Frederico Leite Fontes, Izabel
Chistina de Palmer Paixão Frugulhetti and
Dumith Chequer Bou-Habib
We describe in this paper that the chloroxoquinolinic
ribonucleoside 6-chloro-1,4-dihydro-4-oxo-1-(β-D-ribofuranosyl)-quinoline-3-carboxylic
acid (compound A) inhibits the HIV-1
replication in human primary cells. We initially observed
that compound A inhibited HIV-1 infection
in peripheral blood mononuclear cells (PBMCs) in a dosedependent
manner, resulting in an EC50
of 1.5 ± 0.5 μM
and in a selective index of 1134. Likewise, compound A
blocked HIV-1BA-L replication
in macrophages in a dose-dependent manner, with an EC50
equal to 4.98 ± 0.9 μM.
The replication of HIV-1 isolates from subtypes C and F was
also inhibited by compound A with
the same efficiency. Compound A inhibited
an early event of the HIV-1 replicative cycle, since it prevented
viral DNA synthesis in PBMCs exposed to HIV-1. Kinetic assays
demonstrated that compound A inhibits
the HIV-1 enzyme reverse transcriptase (RT) in dose-dependent
manner, with a KI equal to
0.5 ± 0.04 μM.
Using a panel of HIV-1 isolates harboring NNRTI resistance
mutations, we found a low degree of cross-resistance between
compound A and clinical available
NNRTIs. In addition, compound A exhibited
additive effects with the RT inhibitors AZT and nevirapine,
and synergized with the protease inhibitor atazanavir. Our
results encourage continuous studies about the kinetic impact
of compound A towards different catalytic
forms of RT enzyme, and suggest that our nucleoside represents
a promising molecule for future antiretroviral drug design.
[Back to top]
Transcytosis-Blocking Abs Elicited by an Oligomeric
Immunogen Based on the Membrane Proximal Region of HIV-1 gp41
Target Non-Neutralizing Epitopes
Nobuyuki Matoba, Tagan A. Griffin, Michele Mittman,
Jeffrey D. Doran, Annette Alfsen, David C. Montefiori, Carl
V. Hanson, Morgane Bomsel and Tsafrir S. Mor
CTB-MPR649-684, a translational
fusion protein consisting of cholera toxin B subunit (CTB)
and residues 649 684 of gp41 membrane proximal region (MPR),
is a candidate vaccine aimed at blocking early steps of HIV-1
mucosal transmission. Bacterially produced CTB MPR649-684
was purified to homogeneity by two affinity chromatography
steps. Similar to gp41 and derivatives thereof, the MPR domain
can specifically and reversibly self-associate. The affinities
of the broadly-neutralizing monoclonal Abs 4E10 and 2F5 to
CTB MPR649-684 were equivalent
to their nanomolar affinities toward an MPR peptide. The fusion
protein’s affinity to GM1 ganglioside was comparable
to that of native CTB. Rabbits immunized with CTB-MPR649-684
raised only a modest level of anti-MPR649-684
Abs. However, a prime-boost immunization with CTB-MPR649-684
and a second MPR649-684-based
immunogen elicited a more productive anti-MPR649-684
antibody response. These Abs strongly blocked the epithelial
transcytosis of a primary subtype B HIV-1 isolate in a human
tight epithelial model, expanding our previously reported
results using a clade D virus. The Abs recognized epitopes
at the N-terminal portion of the MPR peptide, away from the
2F5 and 4E10 epitopes and were not effective in neutralizing
infection of CD4+ cells. These results indicate distinct vulnerabilities
of two separate interactions of HIV-1 with human cells –
Abs against the C-terminal portion of the MPR can neutralize
CD4+-dependent infection, while Abs targeting the MPR’s
N-terminal portion can effectively block galactosyl ceramide
dependent transcytosis. We propose that Abs induced by MPR649-684-based
immunogens may provide broad protective value independent
of infection neutralization.
[Back to top]
Suppression of HIV Replication In Vitro by
CpG and CpG Conjugated to the Non Toxic B Subunit of Cholera
Toxin
Salma Nowroozalizadeh, Marianne Jansson, Jenni Adamsson,
Marianne Lindblad, Eva-Maria Fenyö, Jan Holmgren and
Ali M. Harandi
Administration of oligodeoxynucleotides (ODNs) containing
CpG motifs generates a rapid and potent response of CC-chemokines,
known as ligands of the HIV-1 co-receptor CCR5, in the murine
female genital tract. The present study explored the potential
HIV inhibitory activities of different human CpG prototypes
either alone or conjugated to the non-toxic subunit of cholera
toxin (CTB). Results showed that in vitro replication
of both HIV-1 and HIV-2 can be suppressed by different human
CpG prototypes. Importantly, the conjugation of CpG ODN to
CTB (CTB-CpG) enhanced the antiviral activity of CpG against
primary HIV-1 isolates of both R5 and X4 phenotypes in peripheral
blood mononuclear cells (PBMC) as well as U87.CD4 co-receptor
indicator cells. CTB-CpGs triggered higher amounts of MIP-1α,
and MIP-1β
in PBMC than the corresponding CpG ODNs, which may explain
the superior antiviral effect of CTB-CpG against R5 virus
in PBMC. Incubation of PBMC with CpG ODN and CTB-CpG did not
alter surface expression of HIV-1 receptors indicating that
the observed anti-HIV-1 effect is not mediated through down
regulation of HIV-1 receptors on target cells. Further, the
enhanced antiviral effect of CTB-CpG was dependent on the
presence of phosphorothioate backbone in the ODN, whereas
the presence of CpG motif in ODNs was dispensable. These results
have implications for the development of novel intervention
strategies to prevent HIV infection.
[Back to top]
Relative Dominance of Env-gp41-Specific Cytotoxic
T Lymphocytes Responses in HIV-1 Advanced Infection
Yan Zhuang, Yongtao Sun, Song Zhai, Dedong Huang,
Shuguang Zhao, Shaoyang Wang, Wenzhen Kang, Xinhong Li, Bruce
D. Walker, Marcus Altfeld and Xu G. Yu
Human immunodeficiency virus type 1 (HIV-1)-specific
cytotoxic T lymphocytes (CTL) responses provide an important
defense in controlling HIV-1 replication, but they fail to
control the progression of AIDS in advanced HIV-1 infection.
To uncover the situation of these responses in patients with
advanced HIV-1 infection, we assessed HIV-1-specific CTL responses
in 20 individuals with advanced HIV-1 infection using 407
overlapping peptides spanning all expressed HIV-1 proteins
using a gamma interferon–enzyme-linked immunospot (ELISpot)
assay. In comparison to 20 individuals with moderately advanced
HIV-1 infection, HIV-1-specific CTL responses were significantly
decreased (P=0.044) and less peptides could be recognized
(P=0.05) in advanced HIV-1 infection. Weakening of
Env-gp120 and Gag-specific CTL responses contributed importantly
to the decrease of CTL magnitude (P=0.042 and 0.078,
respectively), while Env-gp41-specific CTL responses were
relatively stronger during the end-stage of HIV-1 infection
(P<0.001). Nef and Env-gp41 represented the most
frequently targeted HIV-1 proteins in advanced HIV-1 infection.
The entropy scores of peptides targeted in two groups were
not significantly different. Only the breadth and magnitude
of Env-gp41-specific CTL responses were positively correlated
with viral loads in advanced HIV-1 infection (P=0.005
and 0.001, respectively). These findings suggest that progressive
HIV-1 infection is associated with a weakening of Env-gp120-
and Gag-specific CTL responses, and a simultaneous expansion
of Envgp41-specific CTL which is likely driven by high level
viral replication.
[Back to top]
CADA, a Potential Anti-HIV Microbicide that Specifically
Targets the Cellular CD4 Receptor
Kurt Vermeire, Joachim Brouwers, Yven Van Herrewege,
Roger Le Grand, Guido Vanham, Patrick Augustijns, Thomas W.
Bell and Dominique Schols
The cyclotriazadisulfonamide (CADA) compounds are a new
class of specific CD4-targeted HIV entry inhibitors. The in
vitro anti-HIV activity of CADA was shown to correlate
with its ability to specifically downmodulate cell surface
expression of the CD4 receptor in human cells. Here, we evaluated
its potential as an anti-HIV microbicide. CADA exerted a clear
CD4 receptor downregulating effect in dendritic cells (DC)
and subsequently inhibited HIV-1BaL
replication in DC/T cell co-cultures. The compound proved
to be active against a variety of clinical isolates belonging
to the HIV-1 subtypes A, B, C, D, F, G, H, AE and O. Furthermore,
it prevented human T cells from being infected with the laboratory-adapted
strains X4 HIV-1NL4.3 and
R5 SIVmac251. Flow cytometric
analysis demonstrated a significant and dosedependent downregulation
of CD4 on macaque PBMCs. In addition, the compound exerted
a marked anti-SIVmac251 activity
in these cells from simian origin. The combination of CADA
with cellulose acetate phthalate (CAP) resulted in a synergistic
inhibition of HIV-1 and SIV infection. Finally, gel formulated
CADA proved to preserve the CD4 downmodulating and antiviral
activity of this compound when formulated as a microbicide
gel. Thus, our data suggest that CADA may have potential as
a broad-spectrum anti-HIV microbicide drug candidate. The
preservation of the activity of gel formulated CADA will make
it now feasible for testing this unique entry inhibitor in
non-human primates, not only as a single drug but also in
a synergistic conjunction with other anti-HIV compounds.
[Back to top]
Mortality and Morbidity of HIV Infected Patients Receiving
HAART: A Cohort Study
George Panos, George Samonis, Vangelis G. Alexiou, Garyfallia
A. Kavarnou, Gerasimos Charatsis and Matthew E. Falagas
HAART has substantially decreased mortality and morbidity
among HIV-infected patients. We retrospectively analyzed morbidity
and mortality in a cohort of HIV-infected adult patients with
prolonged and frequent follow up (1987-2006). The study was
divided in pre-HAART and HAART period for comparative reasons.
In total, 615 HIV-infected patients (54 females) were included
in our study. 144 died during the pre-HAART period (51.4 deaths
per 100 patients). During the HAART period only 38 patients
died from a total of 335 patients receiving HAART (11.3 deaths
per 100 patients); the follow up in this part of the cohort
was 2139 persons-years and the death incidence 1.77 deaths/per
100 person-years. The subanalysis excluding patients who died
within 3 months from admission showed that death incidence
among patients that have been receiving HAART from the time
of diagnosis (1.2 deaths per 100 person-years) was slightly
lower, compared to the death incidence of patients treated
for some time with non-HAART as well (1.58 deaths per 100
persons-years). After the availability of HAART in this unit,
the proportion of non-AIDS related deaths increased significantly
from 8% to 40% (p<0.001); infections remained the leading
cause of death in both groups of patients. The most common
non-AIDS related causes of deaths were cancer and coronary
disease. Our data from the studied cohort adds to the relevant
literature regarding the dramatic reduction of morbidity and
mortality that occurred after the availability of HAART.
[Back to top]
HIV-1 Residual Viremia and Proviral DNA in Patients with Suppressed
Plasma Viral Load (<400 HIV-RNA cp/ml) During Different
Antiretroviral Regimens
Emanuele Nicastri, Lucia Palmisano, Loredana
Sarmati, Gabriella D’Ettorre, Saverio Parisi, Mauro
Andreotti, Annarita Buonomini, Franca M. Pirillo, Pasquale
Narciso, Rita Bellagamba, Vincenzo Vullo, Marco Montano, Giovanni
Di Perri and Massimo Andreoni
Low levels of plasma viremia (below 50 copies/ml of HIV-1
RNA) can be detected in the majority of HIV+ subjects successfully
treated with HAART. Aim of our study was to evaluate the impact
of different antiretroviral regimens on this residual viremia
and on proviral HIV-1 DNA in HAART-treated subjects with plasma
HIV RNA <400 cp/ml and no history of virological failure.
To this purpose, a cross-sectional analysis of 319 HIV-positive
patients on HAART with plasma HIV RNA <400 cp/ml was performed.
Subjects had been on HAART for a median of 3.6 years: the
current regimen included two nucleoside reverse transcriptase
inhibitors (NRTIs) plus a protease inhibitor (PI) in 104 (32.6%)
cases, of which 73 treated with a boosted PI; two NRTIs plus
a non-NRTI (NNRTI) were prescribed in 166 (52.2%) cases, and
NRTIs-only in 49 cases (15.4%). Patients treated with PI had
the lowest nadir CD4 cell count (237+191 cells/μl)
compared to patients treated with NNRTI (384+192 cells/μl)
or NRTIs-only (387+222 cells/μl).
Cell-associated HIV-1 DNA was measured in 231 subjects. Residual
viremia was measured in 238 subjects with plasma HIV-1 RNA
levels < 50 copies/ml. Multivariate analysis showed that
the use of NNRTI was independently associated to low levels
of residual viremia and high levels of HIV-1DNA, whereas the
use of PI was independently associated to low levels of HIV-1
DNA. The better virological performance of NNRTI in terms
of low residual viremia is consistent with specific literature
data, whereas the greater impact of PI on the viral reservoirs
is noteworthy and needs further investigations.
[Back to top]
Anti-Chlamydophila pneumoniae Antibodies
as Associated Factor for Carotid Atherosclerosis in Patients
with AIDS
Verónica Gaona-Flores, Guadalupe García-Elorriaga,
Maricela Valerio Minero, Emma González-Veyrand, Rogelio
Navarrete-Castro, Norma Palacios-Jiménez, Guillermo
Del Rey-Pineda, César González-Bonilla and
Lorenzo Monasta
Atherosclerosis is a multifactor disease. Lately, infectious
factors such as C. pneumoniae have been found to
be involved. To determine whether the infection by C.
pneumoniae is a risk factor for atherosclerosis in patients
with AIDS. Case-control study on 43 patients with AIDS under
HAART (16 cases and 27 controls). To document atherosclerosis,
a carotid and transcranial Doppler ultrasound was performed.
Anti-C pneumoniae antibodies were searched using
a microimmunofluorescence test for IgM and IgG levels. To
study the associations with risk of atherosclerosis, Odds
Ratios were calculated for each IgG anti-C. pneumoniae
antibody titre. A titre of 1:64 significantly increased the
risk of atherosclero-sis. These results suggest that hypertriglyceridemia
and C. pneumoniae infection coexistence significantly
increases the risk of atherosclerosis. The inverse geometric
average of the antibodies titre against C. pneumoniae
in individuals with atheromatous plaque fell to 64, two titres
above the controls. This difference turned out to be statistically
significant. Ex-posure to C. pneumoniae with antibodies
(IgG) should be considered in any HIV diagnosed patient as
a risk factor for atherosclerosis, having found that the inverse
geometric averages of antibodies titre are significantly different
comparing cases and controls, especially in patients with
dyslipidemia, hypertriglyceridemia or in patients whose treatments
could cause these conditions. In patients with concomitant
hypertriglyceridemia, the association increases up to three
times. It is advisable that AIDS patients take a serological
test to determine exposure to C. pneumoniae, and
to assess treatment options.
[Back to top]
Phase 1 Single Dose Studies to Optimize the Pharmacokinetics
of DG17, a Novel HIV-Protease Inhibitor Pro-Drug, Using Sodium
Bicarbonate and Ritonavir
Catherine L. Cherry, Jennifer F. Hoy, James S.
Rowe, Henry Krum, John Mills and Sharon R. Lewin
DG17 is an orally available prodrug of DG35 (a novel
HIV protease inhibitor with variable pharmacokinetics). These
studies aimed to optimize DG17 pharmacokinetics by gastric
acid neutralization and ritonavir pharmacoenhancement. Both
studies were conducted using a randomized, cross-over design
in which 6 healthy individuals were administered a single
dose of 100mg or 200mg DG17, half with the study intervention
(sodium bicarbonate solution in the first study, low dose
ritonavir in the second). After a one week washout period,
each subject was then administered a second dose of DG17,
with the study intervention only administered to the other
half. Cmax and AUC increases with gastric acid neutralization
were greatest in those with the lowest absorption of DG17
alone. All doses were subsequently given with sodium bicarbonate
solution in the second study. Low-dose ritonavir co-administration
with DG17 increased DG35 Cmax
(median 1437 versus 100 ng/ml, p=0.028) and AUC (median 6975
versus 154ng/ml*hr, p=0.028) compared with DG17 without ritonavir.
Plasma DG35 exceeded the IC90
for HIV for ≥ 12 hours following a single DG17/ritonavir
dose. No significant adverse events occurred. Single dose
DG17 is safe and best administered in a manner preventing
gastric acid degradation and with low-dose ritonavir.
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