Rapid CD4+ T-Lymphocyte Depletion in Rhesus Monkeys Infected with a Simian–Human Immunodeficiency Virus Expressing the Envelope Glycoproteins of a Primary Dual-Tropic Ethiopian Clade C HIV Type 1 Isolate

2004 ◽  
Vol 20 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Mark Cayabyab ◽  
Daniela Rohne ◽  
Georgios Pollakis ◽  
Claudia Mische ◽  
Tseyanish Messele ◽  
...  
1999 ◽  
Vol 73 (2) ◽  
pp. 976-984 ◽  
Author(s):  
Mark Cayabyab ◽  
Gunilla B. Karlsson ◽  
Bijan A. Etemad-Moghadam ◽  
Wolfgang Hofmann ◽  
Tavis Steenbeke ◽  
...  

ABSTRACT In vivo passage of a poorly replicating, nonpathogenic simian-human immunodeficiency virus (SHIV-HXBc2) generated an efficiently replicating virus, KU-1, that caused rapid CD4+T-lymphocyte depletion and AIDS-like illness in monkeys (S. V. Joag, Z. Li, L. Foresman, E. B. Stephens, L.-J. Zhao, I. Adany, D. M. Pinson, H. M. McClure, and O. Narayan, J. Virol. 70:3189–3197, 1996). The env gene of the KU-1 virus was used to create a molecularly cloned virus, SHIV-HXBc2P 3.2, that differed from a nonpathogenic SHIV-HXBc2 virus in only 12 envelope glycoprotein residues. SHIV-HXBc2P 3.2 replicated efficiently and caused rapid and persistent CD4+ T-lymphocyte depletion in inoculated rhesus macaques. Compared with the envelope glycoproteins of the parental SHIV-HXBc2, the SHIV-HXBc2P 3.2 envelope glycoproteins supported more efficient infection of rhesus monkey peripheral blood mononuclear cells. Both the parental SHIV-HXBc2 and the pathogenic SHIV-HXBc2P 3.2 used CXCR4 but none of the other seven transmembrane segment receptors tested as a second receptor. Compared with the parental virus, viruses with the SHIV-HXBc2P 3.2 envelope glycoproteins were more resistant to neutralization by soluble CD4 and antibodies. Thus, changes in the envelope glycoproteins account for the ability of the passaged virus to deplete CD4+ T lymphocytes rapidly and specify increased replicative capacity and resistance to neutralization.


1999 ◽  
Vol 73 (1) ◽  
pp. 436-443 ◽  
Author(s):  
Wayne B. Dyer ◽  
Graham S. Ogg ◽  
Marie-Ange Demoitie ◽  
Xia Jin ◽  
Andrew F. Geczy ◽  
...  

ABSTRACT Proposals for the use of live attenuated human immunodeficiency virus (HIV) type 1 (HIV-1) as a vaccine candidate in humans have been based on the protection afforded by attenuated simian immunodeficiency virus in the macaque model. Although it is not yet known if this strategy could succeed in humans, a study of the Sydney Blood Bank Cohort (SBBC), infected with an attenuated HIV-1 quasispecies with natural nef and nef/long terminal repeat deletions for up to 17 years, could provide insights into the long-term immunological consequences of living with an attenuated HIV-1 infection. In this study, HIV-specific cytoxic T-lymphocyte (CTL) responses in an SBBC donor and six recipients were examined over a 3-year period with enzyme-linked immunospot, tetrameric complex binding, direct CTL lysis, and CTL precursor level techniques. Strong HIV-specific CTL responses were detected in four of seven patients, including one patient with an undetectable viral load. Two of seven patients had weak CTL responses, and in one recipient, no HIV-specific CTLs were detected. High levels of circulating effector and memory HIV-specific CTLs can be maintained for prolonged periods in these patients despite very low viral loads.


1999 ◽  
Vol 73 (2) ◽  
pp. 1708-1714 ◽  
Author(s):  
Lucy Dorrell ◽  
Tao Dong ◽  
Graham S. Ogg ◽  
Simon Lister ◽  
Steve McAdam ◽  
...  

ABSTRACT We present detailed studies of human immunodeficiency virus (HIV)-specific cytotoxic T-lymphocyte (CTL) responses to clade A or C HIV type 1 in three donors infected in East Africa. We define several novel non-clade B CTL epitopes, including some restricted by HLA alleles common in Africans. Although cross-clade CTL recognition of these epitopes does occur, recognition can also be highly clade specific.


2002 ◽  
Vol 76 (12) ◽  
pp. 6376-6381 ◽  
Author(s):  
Sampa Santra ◽  
Dan H. Barouch ◽  
Marcelo J. Kuroda ◽  
Jörn E. Schmitz ◽  
Georgia R. Krivulka ◽  
...  

ABSTRACT Although recent evidence has confirmed the importance of cytotoxic T-lymphocyte (CTL) responses in controlling human immunodeficiency virus type 1 and simian immunodeficiency virus replication, the relevance of the epitopic breadth of those CTL responses remains unexplored. In the present study, we sought to determine whether vaccination can expand CTL populations which recognize a repertoire of viral epitopes that is greater than is typically generated in the course of a viral infection. We demonstrate that potent secondary CTL responses to subdominant epitopes are rapidly generated following a pathogenic simian-human immunodeficiency virus challenge of rhesus monkeys vaccinated with plasmid DNA or recombinant modified vaccinia virus Ankara vaccines. These data indicate that prior vaccination can increase the breadth of the CTL response that evolves after an AIDS virus infection.


2020 ◽  
Vol 94 (10) ◽  
Author(s):  
Lawrence J. Tartaglia ◽  
Siddhant Gupte ◽  
Kevin C. Pastores ◽  
Sebastien Trott ◽  
Peter Abbink ◽  
...  

ABSTRACT Simian-human immunodeficiency virus (SHIV) infection of rhesus monkeys is an important preclinical model for human immunodeficiency virus type 1 (HIV-1) vaccines, therapeutics, and cure strategies. SHIVs have been optimized by incorporating HIV-1 Env residue 375 mutations that mimic the bulky or hydrophobic residues typically found in simian immunodeficiency virus (SIV) Env to improve rhesus CD4 binding. We applied this strategy to three SHIV challenge stocks (SHIV-SF162p3, SHIV-AE16, and SHIV-325c) and observed three distinct outcomes. We constructed six Env375 variants (M, H, W, Y, F, and S) for each SHIV, and we performed a pool competition study in rhesus monkeys to define the optimal variant for each SHIV prior to generating large-scale challenge stocks. We identified SHIV-SF162p3S/wild type, SHIV-AE16W, and SHIV-325cH as the optimal variants. SHIV-SF162p3S could not be improved, as it already contained the optimal Env375 residue. SHIV-AE16W exhibited a similar replicative capacity to the parental SHIV-AE16 stock. In contrast, SHIV-325cH demonstrated a 2.6-log higher peak and 1.6-log higher setpoint viral loads than the parental SHIV-325c stock. These data demonstrate the diversity of potential outcomes following Env375 modification in SHIVs. Moreover, the clade C SHIV-325cH challenge stock may prove useful for evaluating prophylactic or therapeutic interventions against clade C HIV-1. IMPORTANCE We sought to enhance the infectivity of three SHIV stocks by optimization of a key residue in human immunodeficiency virus type 1 (HIV-1) Env (Env375). We developed the following three new simian-human immunodeficiency virus (SHIV) stocks: SHIV-SF162p3S/wild type, SHIV-AE16W, and SHIV-325cH. SHIV-SF162p3S could not be optimized, SHIV-AE16W proved comparable to the parental virus, and SHIV-325cH demonstrated markedly enhanced replicative capacity compared with the parental virus.


2005 ◽  
Vol 79 (5) ◽  
pp. 2956-2963 ◽  
Author(s):  
Michael S. Seaman ◽  
Ling Xu ◽  
Kristin Beaudry ◽  
Kristi L. Martin ◽  
Margaret H. Beddall ◽  
...  

ABSTRACT The development of a human immunodeficiency virus type 1 (HIV-1) vaccine that elicits potent cellular and humoral immune responses recognizing divergent strains of HIV-1 will be critical for combating the global AIDS epidemic. The present studies were initiated to examine the magnitude and breadth of envelope (Env)-specific T-lymphocyte and antibody responses generated by vaccines containing either a single or multiple genetically distant HIV-1 Env immunogens. Rhesus monkeys were immunized with DNA prime-recombinant adenovirus boost vaccines encoding a Gag-Pol-Nef polyprotein in combination with either a single Env or a mixture of clade-A, clade-B, and clade-C Envs. Monkeys receiving the multiclade Env immunization developed robust immune responses to all vaccine antigens and, importantly, a greater breadth of Env recognition than monkeys immunized with vaccines including a single Env immunogen. All groups of vaccinated monkeys demonstrated equivalent immune protection following challenge with the pathogenic simian-human immunodeficiency virus 89.6P. These data suggest that a multicomponent vaccine encoding Env proteins from multiple clades of HIV-1 can generate broad Env-specific T-lymphocyte and antibody responses without antigenic interference. This study demonstrates that it is possible to generate protective immune responses by vaccination with genetically diverse isolates of HIV-1.


2006 ◽  
Vol 14 (2) ◽  
pp. 157-167 ◽  
Author(s):  
Neil C. Sheppard ◽  
Sarah L. Davies ◽  
Simon A. Jeffs ◽  
Sueli M. Vieira ◽  
Quentin J. Sattentau

ABSTRACT Human (Hu) monoclonal antibodies (MAbs) against the human immunodeficiency virus type 1 (HIV-1) envelope glycoproteins (Env) are useful tools in the structural and functional analysis of Env, are under development both as potential prophylaxis and as therapy for established HIV-1 infection, and have crucial roles in guiding the design of preventative vaccines. Despite representing more than 50% of infections globally, no MAbs have been generated in any species against C clade HIV-1 Env. To generate HuMAbs to a novel Chinese C clade Env vaccine candidate (primary isolate strain HIV-197CN54), we used BAB5 mice that express a human immunoglobulin (Ig) M antibody repertoire in place of endogenous murine immunoglobulins. When immunized with HIV-197CN54 Env, these mice developed antigen-specific IgM antibodies. Hybridoma fusions using splenocytes from these mice enabled the isolation of two Env-specific IgM HuMAbs: N3C5 and N03B11. N3C5 bound to HIV-1 Env from clades A and C, whereas N03B11 bound two geographically distant clade C isolates but not Env from other clades. These HuMAbs bind conformational epitopes within the immunodominant region of the gp41 ectodomain. N3C5 weakly neutralized the autologous isolate in the absence of complement and weakly enhanced infection in the presence of complement. N03B11 has no effect on infectivity in either the presence or the absence of complement. These novel HuMAbs are useful reagents for the study of HIV-1 Env relevant to the global pandemic, and mice producing human immunoglobulin present a tool for the production of such antibodies.


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