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

28 Abstracts 11229-11233

12th World AIDS Conference

virus. SHIV-C2/1, a chimeric SIVmac239 expressing env gene of a pathogenic
HIV-1 isolate 89.6, was obtained after serial in vivo passages of SHIV-89.6 in
rhesus monkeys and cynomolgus monkeys. SHIV-C2/1 induced high levels of primary viremia (approximately 10ng/ml of p27 protein) at 7-10 day post inoculation
(p.i.) and a remarkable CD4 positive T cell depletion (less than 20 cells/ml) within
2 weeks p.i. by an intravenous inoculation of 20 TCID50 in cynomolgus monkeys.
We compared the gene sequences of principal neutralizing domain (PND)
region and HIV-1 gp41 cytoplasmic tail region of SHIV-C2/1 with those of original
clone SHIV-89.6 and SHIV-89.6P derived from SHIV-89.6 through three serial
passages in rhesus monkeys. Only three amino acid changes, N279D, A284V
and R308E, were found in the PND region of SHIV-89.6P (G.B. Karlsson et al,
1997, J. Virol.). The same three amino acid changes were also observed in the
PND region of SHIV-C2/1. Furthermore in the HIV-1 gp41 cytoplasmic tail region,
140-bp deletion was observed in SHIV-C2/1, which is similar to that in SHIV-89.6P
(G.B. Karlsson et al, 1997, J. Virol.).
SHIV-C2/1 virus is highly pathogenic in cynomolgus monkeys. The PND region of this virus was conserved as compared with that of parental HIV-1/89.6.
SHIV-C2/1-cynomolgus monkey model is thus seemed to be useful for the evaluation of anti-HIV-1 drugs and HIV-1 envelope vaccine.
11229 Co-infection of vervet monkeys with trypanosomes and
SIV leads to rapid disease progression and renders
trypanocidal therapy ineffective
Charity W. Gichuki', S.M. Karanjal, R.M. Ngure', D.M. Kamau', M.G. Otsyula2.
'Ketri PO Box 362, Kenya Trypanosomiasis Research Institute, Kikuyu; 2 nstitute
of Primate Research, Nairobi, Kenya
During routine quarantine check up for monkeys to be used for trypanosomosis
studies, 17 of 42 trapped vervet monkeys were found to be antibody and virus
positive for simian immunodeficiency virus (SIV). A study was then set up to
investigate the role of SIV-trypanosome co-infection on disease progression and
subsequent trypanocidal therapy. 6 of the SIV positive monkeys were infected
with Tb. rhodesiense, KETRI 2537, 4 animals served as controls; 2 were infected
with SIV and 2 with trypanosomes alone. On day 42 of infection, 3 monkeys
were treated with a curative dose of melarsoprol, 3 with a subcurative dose of
diminazene aceturate. Complete blood counts, viraemia, parasitaemia and clinical status were used as markers for disease progression and compared to the
monkeys with either SIV or trypanosomes alone. There were no differences in
total white cell counts and differential white cell counts between the SIV infected
and SIV free monkeys. In addition, no differences in the total and differential white
cell counts were observed between monkeys infected with a single pathogen,
and no differences in the total and differential white cell trends after infection
with trypanosomes. However, an increase in viral load was recorded in 3 animals 5 weeks after infection with trypmosomes. During post-treatment follow-up,
all three diminazene aceturate-treated animals showed relapse of parasitaemia
within the first week, compared to 7 weeks in SIV negative animals. In addition, 2
melarsoprol-treated monkeys showed relapse of parasitaemia within 2 weeks of
infection.
These results indicate that the co-infection alters the rate of disease progression and adversely affects trypanocidal chemotherapy. This finding might
explain the rapid disease course in some HIV infected patients in regions endemic for trypanosomosis and warrants vigorous studies to be undertaken to
investigate the role of trypanosome-HIV co-infection in human population at risk
for both pathogens. There is potential for SIV-trypanosomosis monkey model for
HIV-trypanosomosis infections in man.
S11230 CD4/GP120mac251 and phospholipase A2 activation in
cynomolgus monkey lymphocytes
Elie Mavoungou, Virginie Poaty-Mavoungou. CIRMF BP 769, France Ville,
Gabon
Cynomolgus monkey are susceptible to infection with select simian immuno-deficiency virus (SIV). To date, the precise sequence of events following gp120-CD4
interaction, induced the conformational change, and those preceding fusion, are
unknown. We investigated the early interactions between SIV envelope glycoproteins (gp120mac251) and macaque lymphocytes. The SIV like HIV-1 and HIV-2
has been shown to require fusion co-receptors on CD4+ target cell for viral entry.
Our results demonstrate that the soluble viral glycoprotein induces a specific phospholipase A2 (PLA2) activation in lymphocytes through CD4. PLA2 generates
lysophospholipids active as biological detergents that are lytic to membranes. The
PLA2 activation, induced after envelope glycoprotein-CD4 interaction, because
of its locally destabilizing mambrane effect, may have important implications for
preparing the lymphocyte membrane for fusion with the viral particle. However,
this effect is not sufficient to accomplish fusion. These data indicate that the
specific step of fusion may be downstream from PLA2 activation.
We now postulate that, the trimolecular complexe gp120-CD4- co-receptor
induces PLA2 activation through protein kinase C (PKC) and may play a critical
r1le in the fusion between membrane phospholipides of cellular host and gp41

before entry of the virus in lymphocytes.

-11231 Long-term observation of normal and
immunosuppressed rabbits after intraocular inoculation
of human cytomegalovirus (CMV)
Jose Fernando De Castro Figueiredo', L.T. Moraes Figueiredo2, C.R.O.
Cicconelli Sauaia3, E.C. Canarin de Oliveira3, E. Romao3, F.L. Mascardo Da
Silva3, M.L. Veronese Rodrigues3. 'Guaranta 76, Jardim Recreio, 14020-700
Ribeirao Preto-SP; 2Faculty of Medicine Rib Preto-US P FM R PUS P, Ribeirao
Preto SP; 3FM R P US P Ribeirao Preto SP Brasil
Objectives: To investigate the long-term course of intraocular lesions experimentally induced by human CMV in normal and immunossupressed rabbits, in order
to obtain an animal model of CMV retinitis.
Design: A prospective, experimental study.
Methods: Group 1 - single doses of CMV (in three different titers - 102.5TCID50,
101 5TCID50 and 1005TCIDso) were inoculated intravitreouslly, in a 0.1 ml volume,
in normal rabbits. Group 2: single doses of CMV (titer 1025TCIDso) were inoculated intravitreouslly in rabbits with induced immunossupression with Azathioprine
and Prednisone. The rabbits were examined by inspection and indirect binocular
ophthalmoscopy during a period of at least 126 days after CMV inoculation. At the
end of the follow-up period "inprints" of retinal tissue were made for identification
of CMV antigens.
Results: The animals presented different degrees of ocular damage depending
on the CMV doses used. The severity of the lesions and the duration of the ocular
changes were related to the concentration of the virus inoculum and were similar
in the two groups, but the immunossupressed rabbits presented more intense exsudative lesions. CMV antigens were detected in the retinal tissue in the animals
of the normal group eighteen weeks after inoculation, despite the spontaneous
resolution of the ocular lesions after the eleventh week of observation. In the
other hand, in the immunossupressed group, it was not possible to identify CMV
antigens at the end of the follow-up.
Conclusions: The intraocular injection of human CMV causes retinitis in normal and immunossupressed rabbits. Despite this, the spontaneous resolution
of the lesions in both groups and the lack of detection of CMV antigens in he
retinal tissue of the immunossupressed animals at the end of the follow-up argues
against this model of CMV retinitis.
S11232 Experimental transmission of SIVrcm isolated from red
capped mangabey to Macaque
Maria Makuwa1, M.C. Georges-Gourbot', C.Y. Lu', G. Dubreuil', P.A. Marx2,
A.J. Georges'. 'Centre International de Recherches Medicales (CIRMF)
Franceville BP 769, Gabon; 2Aaron Diamond AIDS Research Center, New York,
USA
Objective: A new virus SIVrcm was isolated in a red capped mangabey (Cercocebus torquatus torquatus) from Central Africa. An experimental study was done
to evaluate the ability of SIVrcm in infecting macaque monkeys. As red capped
mangabey is closely related to sooty mangabey (Cercocebus torquatus atys), we
made an attempt to analyse that SIVrcm can infect macaque in a way similar to
SIVsmm.
Design: Experimental transmission study
Methods: Ten ml of heparinized total blood from naturally infected monkey
RCM9 was injected intravenously into two macaques (H657, J499). Virological,
immunological and clinical follow-up of experimentally infected animals was carried out periodically (DO, D11, D14, D30, D45, D60, D70 after transfusion) and
routine examinations of spleen, ganglion, body weight and weakfullness were
carried out each time of anaesthesia.
Results: The presence of the virus was detected in PBMC of macaque J499
cocultivated with PBMC of negative macaque at D11 and D45 after transfusion.
The presence of antibodies anti-Gp105 was observed at D45 after transfusion in
J499 and at D60 in H657. The profile of HIV2 was observed in both macaques
from D90 after transfusion. Both remain symptomless up to 20 months post
infection.
Conclusion: Only one transfusion may not be sufficient to induce symptoms in
macaques. Further transmissions from macaque J499 to non-infected macaques
can elicit AIDS-related symptoms.
556*/11233 Abacavir (1592, ABC) prevents spread of HIV-1 in
brain tissue of SCID mice with HIV-1 encephalitis
Jenae Limoges1, D.R. McClernon2, Y. Persidsky1, J. Rasmussen1, E.R. Lanier2,
J. Reinhard2, H.E. Gendelman1'. ' Center for Neurovirology 600 S. 42nd St.
Omaha NE 68198-5215; 2Glaxowellcome Inc. Res. Triangle Park NC, USA
Objectives: The eradication of HIV-1 from hidden sanctuaries remains a major
concern for efficacy of highly active anti-retroviral therapy (HAART). Because
many of the newer HAART penetrate the brain poorly, if at all, the central nervous
system (CNS) remains an important reservoir for viral replication and a focus
for new drug development. To these ends, we tested whether 1592, a novel
nucleoside reverse transcriptase inhibitor from GlaxoWellcome, could eradicate

persistent vital replication in the CNS. ABC is reported to be more potent against
HIV-1 replication than zidovudine (ZDV) and to achieve similar brain drug levels.
Methods: A recently developed SCID mouse model of HIV-1 encephalitis was
modified to permit spreading viral replication in the CNS. Human HIV-1 infected
monocytes are stereotactically inoculated into the putamen and deep cortical
structures; those most involved in vital encephalitis. This results in a multinucleated giant cell encephalitis with viral gene expression, microglial nodules, gliosis