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1.
J Virol ; 83(17): 8353-63, 2009 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-19553323

RESUMO

Human immunodeficiency virus type 1 (HIV-1) infects target cells by binding to CD4 and a chemokine receptor, most commonly CCR5. CXCR4 is a frequent alternative coreceptor (CoR) in subtype B and D HIV-1 infection, but the importance of many other alternative CoRs remains elusive. We have analyzed HIV-1 envelope (Env) proteins from 66 individuals infected with the major subtypes of HIV-1 to determine if virus entry into highly permissive NP-2 cell lines expressing most known alternative CoRs differed by HIV-1 subtype. We also performed linear regression analysis to determine if virus entry via the major CoR CCR5 correlated with use of any alternative CoR and if this correlation differed by subtype. Virus pseudotyped with subtype B Env showed robust entry via CCR3 that was highly correlated with CCR5 entry efficiency. By contrast, viruses pseudotyped with subtype A and C Env proteins were able to use the recently described alternative CoR FPRL1 more efficiently than CCR3, and use of FPRL1 was correlated with CCR5 entry. Subtype D Env was unable to use either CCR3 or FPRL1 efficiently, a unique pattern of alternative CoR use. These results suggest that each subtype of circulating HIV-1 may be subject to somewhat different selective pressures for Env-mediated entry into target cells and suggest that CCR3 may be used as a surrogate CoR by subtype B while FPRL1 may be used as a surrogate CoR by subtypes A and C. These data may provide insight into development of resistance to CCR5-targeted entry inhibitors and alternative entry pathways for each HIV-1 subtype.


Assuntos
Infecções por HIV/virologia , HIV-1/fisiologia , Receptores CCR3/metabolismo , Receptores de Formil Peptídeo/metabolismo , Receptores de Lipoxinas/metabolismo , Receptores Virais/metabolismo , Internalização do Vírus , Linhagem Celular , HIV-1/genética , Humanos , Dados de Sequência Molecular , Análise de Sequência de DNA , Produtos do Gene env do Vírus da Imunodeficiência Humana/genética
2.
J Virol ; 75(22): 10892-905, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11602729

RESUMO

The identification and epitope mapping of broadly neutralizing anti-human immunodeficiency virus type 1 (HIV-1) antibodies (Abs) is important for vaccine design, but, despite much effort, very few such Abs have been forthcoming. Only one broadly neutralizing anti-gp41 monoclonal Ab (MAb), 2F5, has been described. Here we report on two MAbs that recognize a region immediately C-terminal of the 2F5 epitope. Both MAbs were generated from HIV-1-seropositive donors, one (Z13) from an antibody phage display library, and one (4E10) as a hybridoma. Both MAbs recognize a predominantly linear and relatively conserved epitope, compete with each other for binding to synthetic peptide derived from gp41, and bind to HIV-1(MN) virions. By flow cytometry, these MAbs appear to bind relatively weakly to infected cells and this binding is not perturbed by pretreatment of the infected cells with soluble CD4. Despite the apparent linear nature of the epitopes of Z13 and 4E10, denaturation of recombinant envelope protein reduces the binding of these MAbs, suggesting some conformational requirements for full epitope expression. Most significantly, Z13 and 4E10 are able to neutralize selected primary isolates from diverse subtypes of HIV-1 (e.g., subtypes B, C, and E). The results suggest that a rather extensive region of gp41 close to the transmembrane domain is accessible to neutralizing Abs and could form a useful target for vaccine design.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Especificidade de Anticorpos , Ensaio de Imunoadsorção Enzimática , Epitopos , Citometria de Fluxo , Proteína gp41 do Envelope de HIV/química , Humanos , Dados de Sequência Molecular , Testes de Neutralização
3.
J Virol ; 75(22): 10906-11, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11602730

RESUMO

Matrix-assisted laser desorption ionization mass spectrometry (MALDI-MS), in combination with proteolytic protection assays, has been used to identify the functional epitope on human immunodeficiency virus envelope glycoprotein gp41 for the broadly neutralizing anti-gp41 human monoclonal antibody 2F5. In this protection assay-based procedure, a soluble gp140 protein with a stabilizing intermolecular disulfide bond between the gp120 and gp41 subunits (SOS gp140) was affinity bound to immobilized 2F5 under physiological conditions. A combination of proteolytic enzymatic cleavages was then performed to remove unprotected residues. Residues of SOS gp140 protected by their binding to 2F5 were then identified based on their molecular weights as determined by direct MALDI-MS of the immobilized antibody beads. The epitope, NEQELLELDKWASLWN, determined by this MALDI-MS protection assay approach consists of 16 amino acid residues near the C terminus of gp41. It is significantly longer than the ELDKWA core epitope previously determined for 2F5 by peptide enzyme-linked immunosorbent assay. This new knowledge of the structure of the 2F5 epitope may facilitate the design of vaccine antigens intended to induce antibodies with the breadth and potency of action of the 2F5 monoclonal antibody.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/imunologia , Vacinas contra a AIDS/imunologia , Sequência de Aminoácidos , Animais , Células CHO , Cricetinae , Mapeamento de Epitopos , Proteína gp41 do Envelope de HIV/química , Humanos , Espectrometria de Massas , Dados de Sequência Molecular , Testes de Neutralização
4.
J Infect Dis ; 182(3): 945-9, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10950795

RESUMO

The effect on humoral immune responses of highly active antiretroviral therapy (HAART) commenced during primary or chronic human immunodeficiency virus type 1 (HIV-1) infection was investigated. HAART inhibited the development of anti-gp120 antibodies when initiated during primary infection and could sometimes reduce antibody titers in patients treated within 2 years of HIV-1 infection. Conversely, antibody responses in patients infected for several years were less sensitive to HAART. Administering HAART during primary infection usually did not substantially affect the development of weak neutralizing antibody responses against autologous virus. However, 2 patients treated very early after infection did not develop neutralizing responses. In contrast, 3 of 4 patients intermittently adherent to therapy developed autologous neutralizing antibodies of unusually high titer, largely coincident with brief viremic periods. The induction of strong neutralizing antibody responses during primary HIV-1 infection might require the suppression of virus replication by HAART, to allow for the recovery of immune competency, followed by exposure to native envelope glycoproteins.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Anticorpos Anti-HIV/biossíntese , Infecções por HIV/tratamento farmacológico , Infecções por HIV/imunologia , HIV-1 , Fármacos Anti-HIV/administração & dosagem , Carbamatos , Didesoxinucleosídeos/administração & dosagem , Didesoxinucleosídeos/uso terapêutico , Furanos , Proteína do Núcleo p24 do HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Humanos , Lamivudina/administração & dosagem , Lamivudina/uso terapêutico , Testes de Neutralização , Ritonavir/administração & dosagem , Ritonavir/uso terapêutico , Sulfonamidas/administração & dosagem , Sulfonamidas/uso terapêutico , Zidovudina/administração & dosagem , Zidovudina/uso terapêutico
5.
J Virol ; 74(11): 5091-100, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10799583

RESUMO

We have described an oligomeric gp140 envelope glycoprotein from human immunodeficiency virus type 1 that is stabilized by an intermolecular disulfide bond between gp120 and the gp41 ectodomain, termed SOS gp140 (J. M. Binley, R. W. Sanders, B. Clas, N. Schuelke, A. Master, Y. Guo, F. Kajumo, D. J. Anselma, P. J. Maddon, W. C. Olson, and J. P. Moore, J. Virol. 74:627-643, 2000). In this protein, the protease cleavage site between gp120 and gp41 is fully utilized. Here we report the characterization of gp140 variants that have deletions in the first, second, and/or third variable loop (V1, V2, and V3 loops). The SOS disulfide bond formed efficiently in gp140s containing a single loop deletion or a combination deletion of the V1 and V2 loops. However, deletion of all three variable loops prevented formation of the SOS disulfide bond. Some variable-loop-deleted gp140s were not fully processed to their gp120 and gp41 constituents even when the furin protease was cotransfected. The exposure of the gp120-gp41 cleavage site is probably affected in these proteins, even though the disabling change is in a region of gp120 distal from the cleavage site. Antigenic characterization of the variable-loop-deleted SOS gp140 proteins revealed that deletion of the variable loops uncovers cryptic, conserved neutralization epitopes near the coreceptor-binding site on gp120. These modified, disulfide-stabilized glycoproteins might be useful as immunogens.


Assuntos
Dissulfetos/metabolismo , Produtos do Gene env/metabolismo , Variação Genética , Proteína gp120 do Envelope de HIV/metabolismo , Proteína gp41 do Envelope de HIV/metabolismo , HIV-1/metabolismo , Sequência de Aminoácidos , Sítios de Ligação , Antígenos CD4/metabolismo , Epitopos de Linfócito B , Produtos do Gene env/genética , Proteína gp120 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/genética , HIV-1/genética , Humanos , Dados de Sequência Molecular , Mutagênese , Processamento de Proteína Pós-Traducional , Produtos do Gene env do Vírus da Imunodeficiência Humana
6.
J Infect Dis ; 181(4): 1249-63, 2000 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10762561

RESUMO

The relationship between human immunodeficiency virus (HIV) type 1 replication and CD4+ T cell function was examined. T lymphocyte proliferation in response to both HIV-1 antigens and recall antigens was measured in HIV-1-infected individuals before and after they received highly active antiretroviral therapy (HAART). No correlation was observed between baseline viral load or CD4+ T cell count and the T cell proliferative response to HIV-1 Gag. Suppression of viremia was not associated with an increase in T cell proliferative responses. Emergence of viral replication during short periods of intermittent therapy promoted generalized activation of T helper lymphocytes, manifested by increased T cell proliferative responses to HIV-1 Gag and recall antigens. Recovery of CD4+ T cell responses occurred in some individuals who initiated HAART years after infection and who were intermittently adherent to drug treatment. Thus, CD4+ T cell responses can sometimes be regenerated if viral load is suppressed to allow some immune recovery and if antigenic stimulation is later provided.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/tratamento farmacológico , HIV-1 , Linfócitos T/citologia , Viremia/tratamento farmacológico , Instituições de Assistência Ambulatorial , Fármacos Anti-HIV/administração & dosagem , Contagem de Linfócito CD4 , Divisão Celular , Quimioterapia Combinada , Proteína do Núcleo p24 do HIV/análise , Humanos , Fatores de Tempo , Carga Viral
7.
Virology ; 270(1): 237-49, 2000 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-10772996

RESUMO

Antibody responses are often considered to play only a limited role in controlling viremia during chronic infections with human or simian immunodeficiency virus (SIV). We investigated this by determining the effect of passively infused antibody on plasma viremia in infected rhesus macaques. The emphasis of the study was to understand the mechanism(s) underlying any observed effects. We infused serum immunoglobulins (SIVIG) purified from SIV(mac)251-infected macaques into other SIV(mac)251-infected macaques. The rapid progressor recipients had high viral loads but negligible titers of antibodies to SIV. Thus, we could significantly increase antibody titers with exogenous SIVIG. Despite restoring anti-SIV titers to levels typical of macaques with a normal disease course, SIVIG had only a modest effect on plasma SIV RNA and cell-associated viral load; the maximum, transient, reduction was threefold. The decrease in plasma RNA commenced within 1-2 h of SIVIG infusion, the nadir was at 12 h, and then a rebound occurred. A two- to threefold drop in cell-associated viral RNA was simultaneous with the decrease in plasma RNA. The kinetics of the viremia changes are inconsistent with neutralization of new cycles of infection. More likely, perhaps unexpectedly, is that infused antibodies killed SIV-infected cells, via an effector mechanism such as antibody-dependent cellular cytotoxicity.


Assuntos
Anticorpos Antivirais/imunologia , Imunização Passiva , Macaca mulatta/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Vírus da Imunodeficiência Símia/imunologia , Vírus da Imunodeficiência Símia/fisiologia , Viremia/imunologia , Animais , Anticorpos Antivirais/administração & dosagem , Anticorpos Antivirais/sangue , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Progressão da Doença , Soros Imunes/administração & dosagem , Soros Imunes/sangue , Soros Imunes/imunologia , Imunoglobulina G/administração & dosagem , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Cinética , Contagem de Linfócitos , Macaca mulatta/virologia , Testes de Neutralização , RNA Viral/sangue , Síndrome de Imunodeficiência Adquirida dos Símios/patologia , Síndrome de Imunodeficiência Adquirida dos Símios/terapia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/isolamento & purificação , Carga Viral , Viremia/patologia , Viremia/terapia , Viremia/virologia
8.
AIDS Res Hum Retroviruses ; 16(3): 259-71, 2000 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-10710214

RESUMO

We have analyzed factors that might influence the in vitro quantitation of the T-proliferative response to HIV-1 Gag antigens, a common and increasingly used clinical measurement of helper T cell function in the context of HIV-1 infection. We have compared the rate and extent of T cell proliferation in freshly prepared and previously frozen PBMC samples, and have concluded that frozen cells can be used successfully; we have assessed whether the suppression of any HIV-1 replication in the PBMC cultures affects the extent of T cell proliferation; we have studied which forms of the Gag antigens are the most efficient at inducing T cell proliferation. From the latter experiments, we conclude that Gag proteins that include p17, and perhaps also p7, sequences flanking the central p24 capsid protein, are better stimulants than proteins that comprise only p24 sequences.


Assuntos
Proteínas do Capsídeo , Produtos do Gene gag/imunologia , Antígenos HIV/imunologia , HIV-1/imunologia , Linfócitos T/imunologia , Proteínas Virais , Fármacos Anti-HIV/farmacologia , Capsídeo/imunologia , Divisão Celular , Células Cultivadas , Eletroforese em Gel de Poliacrilamida/métodos , Congelamento , Proteína do Núcleo p24 do HIV/imunologia , Inibidores da Protease de HIV/farmacologia , Humanos , Microscopia Eletrônica/métodos , Nelfinavir/farmacologia , Nevirapina/farmacologia , Inibidores da Transcriptase Reversa/farmacologia , Linfócitos T/citologia , Linfócitos T/efeitos dos fármacos , Fatores de Tempo , Produtos do Gene gag do Vírus da Imunodeficiência Humana
9.
J Virol ; 74(2): 627-43, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10623724

RESUMO

The few antibodies that can potently neutralize human immunodeficiency virus type 1 (HIV-1) recognize the limited number of envelope glycoprotein epitopes exposed on infectious virions. These native envelope glycoprotein complexes comprise three gp120 subunits noncovalently and weakly associated with three gp41 moieties. The individual subunits induce neutralizing antibodies inefficiently but raise many nonneutralizing antibodies. Consequently, recombinant envelope glycoproteins do not elicit strong antiviral antibody responses, particularly against primary HIV-1 isolates. To try to develop recombinant proteins that are better antigenic mimics of the native envelope glycoprotein complex, we have introduced a disulfide bond between the C-terminal region of gp120 and the immunodominant segment of the gp41 ectodomain. The resulting gp140 protein is processed efficiently, producing a properly folded envelope glycoprotein complex. The association of gp120 with gp41 is now stabilized by the supplementary intermolecular disulfide bond, which forms with approximately 50% efficiency. The gp140 protein has antigenic properties which resemble those of the virion-associated complex. This type of gp140 protein may be worth evaluating for immunogenicity as a component of a multivalent HIV-1 vaccine.


Assuntos
Dissulfetos/metabolismo , Produtos do Gene env/metabolismo , Glicoproteínas/metabolismo , Proteína gp120 do Envelope de HIV/metabolismo , Proteína gp41 do Envelope de HIV/metabolismo , HIV-1 , Sequência de Aminoácidos , Substituição de Aminoácidos , Antígenos Virais/genética , Antígenos Virais/imunologia , Antígenos Virais/metabolismo , Linhagem Celular Transformada , Centrifugação com Gradiente de Concentração , Cromatografia em Gel , Cisteína/genética , Furina , Produtos do Gene env/genética , Produtos do Gene env/imunologia , Glicoproteínas/genética , Glicoproteínas/imunologia , Proteína gp120 do Envelope de HIV/genética , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/genética , Proteína gp41 do Envelope de HIV/imunologia , HIV-1/isolamento & purificação , Humanos , Dados de Sequência Molecular , Processamento de Proteína Pós-Traducional , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Proteínas Recombinantes de Fusão/metabolismo , Subtilisinas/metabolismo , Sacarose , Vírion , Produtos do Gene env do Vírus da Imunodeficiência Humana
10.
Lancet ; 354(9192): 1782-5, 1999 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-10577640

RESUMO

BACKGROUND: In chronic HIV-1 infection, dynamic equilibrium exists between viral production and clearance. The half-life of free virions can be estimated by inhibiting virion production with antiretroviral agents and modelling the resulting decline in plasma HIV-1 RNA. To define HIV-1 and hepatitis C virus (HCV) dynamics, we used plasma apheresis to increase virion clearance temporarily while leaving virion production unaffected. METHODS: Plasma virus loads were measured frequently before, during, and after apheresis in four HIV-1-infected patients, two of whom were also co-infected with HCV. Rates of virion clearance were derived by non-linear least-square fitting of plasma virus load to a model of viral dynamics. FINDINGS: Virion clearance rate constants were 0.0063/min (9.1/day) to 0.025/min (36.0/day; half-life 28-110 min) for HIV-1 and 0.0038/min (5.5/day) to 0.0069/min (9.9/day; half-life 100-182 min) for HCV. These values provided estimates of daily particle production of 9.3 log10-10.2 log10 particles for HIV-1 and 11.6 log10-13.0 log10 particles for HCV. INTERPRETATION: Our findings confirm that HIV-1 and HCV are produced and cleared extremely rapidly. New estimates for HIV-1 clearance are up to ten times higher than previous ones, whereas HCV clearance is similar to previous estimates.


Assuntos
Infecções por HIV/virologia , HIV-1/isolamento & purificação , Hepacivirus/isolamento & purificação , Plasmaferese , Vírion/crescimento & desenvolvimento , DNA Viral/sangue , Infecções por HIV/metabolismo , HIV-1/metabolismo , Meia-Vida , Hepacivirus/metabolismo , Humanos , Taxa de Depuração Metabólica , Modelos Teóricos , RNA Viral/sangue
11.
J Clin Invest ; 104(6): R13-8, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10491418

RESUMO

Therapeutic intervention with highly active antiretroviral therapy (HAART) can lead to suppression of HIV-1 plasma viremia to undetectable levels for 3 or more years. However, adherence to complex drug regimens can prove problematic, and subjects may temporarily discontinue HAART for variable periods. We studied 6 HIV-1-infected individuals who stopped therapy. Off HAART, levels of viremia were suppressed to fewer than 500 copies/mL in 2 subjects for more than 12 and more than 24 months, respectively, and in 1 subject for 4 months on 1 occasion. Three subjects failed to contain plasma viremia. Broad and strong HIV-1-specific immune responses were detected in subjects with prolonged suppression of viral replication. This longitudinal study suggests that containment of HIV-1 replication to low or undetectable levels after discontinuation of HAART is associated with strong virus-specific immune responses. Boosting of HIV-1-specific immune responses should be considered as an adjunctive treatment strategy for HIV-1-infected individuals on HAART.


Assuntos
Síndrome da Imunodeficiência Adquirida/imunologia , Fármacos Anti-HIV/uso terapêutico , HIV-1/imunologia , Replicação Viral , Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Síndrome da Imunodeficiência Adquirida/virologia , Adulto , Proteína do Núcleo p24 do HIV/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , Linfócitos T Citotóxicos/imunologia , Viremia/tratamento farmacológico , Viremia/imunologia
12.
J Infect Dis ; 179(3): 527-37, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9952358

RESUMO

Twelve subjects were treated with zidovudine, lamivudine, and ritonavir within 90 days of onset of symptoms of acute infection to determine whether human immunodeficiency virus type 1 (HIV-1) infection could be eradicated from an infected host. In adherent subjects, with or without modifications due to intolerance, viral replication was suppressed during the 24-month treatment period. Durable suppression reduced levels of HIV-1-specific antibodies and cytotoxic T lymphocyte responses in selected subjects. Proviral DNA in mononuclear cells uniformly persisted. The persistence of HIV-1 RNA expression in lymphoid tissues and peripheral blood mononuclear cells suggests that elimination of this residual pool of virus should be achieved before considering adjustments in antiretroviral therapeutic regimens. In addition, given the reduction in levels of virus-specific immune responses, it would seem prudent to consider enhancing these responses using vaccine strategies prior to the withdrawal of antiviral therapy.


Assuntos
Síndrome da Imunodeficiência Adquirida/tratamento farmacológico , Fármacos Anti-HIV/uso terapêutico , HIV-1/fisiologia , Lamivudina/uso terapêutico , Ritonavir/uso terapêutico , Replicação Viral/efeitos dos fármacos , Zidovudina/uso terapêutico , Síndrome da Imunodeficiência Adquirida/imunologia , Síndrome da Imunodeficiência Adquirida/virologia , Adulto , Quimioterapia Combinada , HIV-1/efeitos dos fármacos , HIV-1/imunologia , Homossexualidade Masculina , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , RNA Viral/sangue , Linfócitos T Citotóxicos/imunologia , Fatores de Tempo , Viremia/sangue , Viremia/tratamento farmacológico
13.
J Virol ; 72(12): 10270-4, 1998 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-9811774

RESUMO

Although typical primary isolates of human immunodeficiency virus type 1 (HIV-1) are relatively neutralization resistant, three human monoclonal antibodies and a small number of HIV-1(+) human sera that neutralize the majority of isolates have been described. The monoclonal antibodies (2G12, 2F5, and b12) represent specificities that a putative vaccine should aim to elicit, since in vitro neutralization has been correlated with protection against primary viruses in animal models. Furthermore, a neutralization escape mutant to one of the antibodies (b12) selected in vitro remains sensitive to neutralization by the other two (2G12 and 2F5) (H. Mo, L. Stamatatos, J. E. Ip, C. F. Barbas, P. W. H. I. Parren, D. R. Burton, J. P. Moore, and D. D. Ho, J. Virol. 71:6869-6874, 1997), supporting the notion that eliciting a combination of such specificities would be particularly advantageous. Here, however, we describe a small subset of viruses, mostly pediatric, which show a high level of neutralization resistance to all three human monoclonal antibodies and to two broadly neutralizing sera. Such viruses threaten antibody-based antiviral strategies, and the basis for their resistance should be explored.


Assuntos
Anticorpos Anti-HIV , HIV-1/imunologia , HIV-1/isolamento & purificação , Animais , Anticorpos Monoclonais , Especificidade de Anticorpos , Criança , Pré-Escolar , Modelos Animais de Doenças , Epitopos/isolamento & purificação , Anticorpos Anti-HIV/sangue , Proteína gp120 do Envelope de HIV/imunologia , Proteína gp120 do Envelope de HIV/isolamento & purificação , Proteína gp41 do Envelope de HIV/imunologia , Proteína gp41 do Envelope de HIV/isolamento & purificação , Infecções por HIV/imunologia , Infecções por HIV/prevenção & controle , Infecções por HIV/virologia , Células HeLa , Humanos , Imunização Passiva , Testes de Neutralização
14.
J Virol ; 72(9): 7501-9, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9696847

RESUMO

Despite evidence that live, attenuated simian immunodeficiency virus (SIV) vaccines can elicit potent protection against pathogenic SIV infection, detailed information on the replication kinetics of attenuated SIV in vivo is lacking. In this study, we measured SIV RNA in the plasma of 16 adult rhesus macaques immunized with a live, attenuated strain of SIV (SIVmac239Deltanef). To evaluate the relationship between replication of the vaccine virus and the onset of protection, four animals per group were challenged with pathogenic SIVmac251 at either 5, 10, 15, or 25 weeks after immunization. SIVmac239Deltanef replicated efficiently in the immunized macaques in the first few weeks after inoculation. SIV RNA was detected in the plasma of all animals by day 7 after inoculation, and peak levels of viremia (10(5) to 10(7) RNA copies/ml) occurred by 7 to 12 days. Following challenge, SIVmac251 was detected in all of the four animals challenged at 5 weeks, in two of four challenged at 10 weeks, in none of four challenged at 15 weeks, and one of four challenged at 25 weeks. One animal immunized with SIVmac239Deltanef and challenged at 10 weeks had evidence of disease progression in the absence of detectable SIVmac251. Although complete protection was not achieved at 5 weeks, a transient reduction in viremia (approximately 100-fold) occurred in the immunized macaques early after challenge compared to the nonimmunized controls. Two weeks after challenge, SIV RNA was also reduced in the lymph nodes of all immunized macaques compared with control animals. Taken together, these results indicate that host responses capable of reducing the viral load in plasma and lymph nodes were induced as early as 5 weeks after immunization with SIVmac239Deltanef, while more potent protection developed between 10 and 15 weeks. In further experiments, we found that resistance to SIVmac251 infection did not correlate with the presence of antibodies to SIV gp130 and p27 antigens and was achieved in the absence of significant neutralizing activity against the primary SIVmac251 challenge stock.


Assuntos
Síndrome de Imunodeficiência Adquirida dos Símios/prevenção & controle , Vírus da Imunodeficiência Símia/imunologia , Vacinas Virais/imunologia , Replicação Viral , Animais , Anticorpos Antivirais/imunologia , Linhagem Celular , Progressão da Doença , Feminino , Deleção de Genes , Produtos do Gene env/imunologia , Produtos do Gene gag/imunologia , Genes nef , Macaca mulatta , Testes de Neutralização , RNA Viral/sangue , Síndrome de Imunodeficiência Adquirida dos Símios/imunologia , Síndrome de Imunodeficiência Adquirida dos Símios/virologia , Vírus da Imunodeficiência Símia/genética , Vírus da Imunodeficiência Símia/fisiologia , Vacinação , Vacinas Atenuadas/imunologia , Carga Viral
15.
J Virol ; 72(8): 6332-8, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-9658072

RESUMO

Infection by some human immunodeficiency virus type 1 (HIV-1) isolates is enhanced by the binding of subneutralizing concentrations of soluble receptor, soluble CD4 (sCD4), or monoclonal antibodies directed against the viral envelope glycoproteins. In this work, we studied the abilities of different antibodies to mediate activation of the envelope glycoproteins of a primary HIV-1 isolate, YU2, and identified the regions of gp120 envelope glycoprotein contributing to activation. Binding of antibodies to a variety of epitopes on gp120, including the CD4 binding site, the third variable (V3) loop, and CD4-induced epitopes, enhanced the entry of viruses containing YU2 envelope glycoproteins. Fab fragments of antibodies directed against either the CD4 binding site or V3 loop also activated YU2 virus infection. The activation phenotype was conferred on the envelope glycoproteins of a laboratory-adapted HIV-1 isolate (HXBc2) by replacing the gp120 V3 loop or V1/V2 and V3 loops with those of the YU2 virus. Infection by the YU2 virus in the presence of activating antibodies remained inhibitable by macrophage inhibitory protein 1beta, indicating dependence on the CCR5 coreceptor on the target cells. Thus, antibody enhancement of YU2 entry involves neither Fc receptor binding nor envelope glycoprotein cross-linking, is determined by the same variable loops that dictate enhancement by sCD4, and probably proceeds by a process fundamentally similar to the receptor-activated virus entry pathway.


Assuntos
Antígenos CD4/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/imunologia , HIV-1/fisiologia , Animais , Anticorpos Monoclonais/imunologia , Células COS , Células Cultivadas , Quimiocina CCL4 , Epitopos de Linfócito B/imunologia , Proteína gp120 do Envelope de HIV/fisiologia , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Proteínas Inflamatórias de Macrófagos/imunologia , Proteínas Recombinantes/imunologia
16.
J Exp Med ; 188(2): 233-45, 1998 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-9670036

RESUMO

We studied how combination antiviral therapy affects B cell abnormalities associated with HIV-1 infection, namely elevated circulating immunoglobulin (Ig)G antibody-secreting cell (ASC) frequencies and hypergammaglobulinemia. Within a few weeks of starting antiviral therapy, there is a marked decline in IgG-ASC frequency in both acutely and chronically infected people, whereas the hypergammaglobulinemia often present during chronic infection is more gradually resolved. These reductions are sustained while HIV-1 replication is suppressed. HIV-1 antigen-specific B cell responses are also affected by therapy, manifested by a rapid decline in circulating gp120-specific ASCs. Anti-gp120 titers slowly decrease in chronically infected individuals and usually fail to mature in acutely infected individuals who were promptly treated with antiretroviral therapy. Long-term nonprogressors have high titer antibody responses to HIV-1 antigens, but no detectable gp120-specific IgG-ASC, and normal (or subnormal) levels of total circulating IgG-ASC. Overall, we conclude that HIV-1 infection drives B cell hyperactivity, and that this polyclonal activation is rapidly responsive to decreases in viral replication caused by combination antiviral therapy.


Assuntos
Antivirais/uso terapêutico , Linfócitos B/imunologia , Anticorpos Anti-HIV/imunologia , Antígenos HIV/imunologia , Infecções por HIV/imunologia , HIV-1/isolamento & purificação , Antivirais/farmacologia , Quimioterapia Combinada , Infecções por HIV/tratamento farmacológico , Humanos
18.
J Virol ; 72(4): 3472-4, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9525685

RESUMO

Long-term nonprogressor AD-18 has been infected with human immunodeficiency virus type 1 (HIV-1) for at least 16 years. During the past 5 years, he has had undetectable levels of plasma viremia, and HIV-1 cannot be isolated from him. Sequencing of proviral DNA indicates that the only HIV-1 sequences that can be identified in AD-18 have gross defects in the p17-encoding regions of the gag gene (Y. Huang, L. Zhang, and D. D. Ho, Virology 240:36-49, 1998). However, AD-18 has strong, sustained antibody responses to several HIV-1 antigens, including p17. Cytotoxic T-lymphocyte responses to Env and Gag antigens have gradually diminished over the past 4 years, at a time when the titers of antibodies to the same proteins have remained stable. We discuss what these observations might mean for the generation and maintenance of immunological memory.


Assuntos
Produtos do Gene gag/genética , Produtos do Gene gag/imunologia , Anticorpos Anti-HIV/imunologia , Antígenos HIV/genética , Antígenos HIV/imunologia , HIV-1/imunologia , RNA Viral , Deleção de Sequência , Linfócitos T Citotóxicos/imunologia , Proteínas Virais , Células Dendríticas/imunologia , Progressão da Doença , Expressão Gênica , Produtos do Gene env/imunologia , Anticorpos Anti-HIV/sangue , Proteína do Núcleo p24 do HIV/imunologia , Proteína gp120 do Envelope de HIV/imunologia , Humanos , Memória Imunológica/imunologia , Estudos Longitudinais , Provírus/genética , Sobreviventes , Produtos do Gene gag do Vírus da Imunodeficiência Humana
19.
AIDS Res Hum Retroviruses ; 14(3): 191-8, 1998 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-9491908

RESUMO

The binding of a panel of monoclonal antibodies to V1, V2, and V3 loop-deleted HIV-1 gp120 was studied by competition analysis. Most of the previously defined relationships between gp120 epitopes were preserved on the variable loop-deleted protein, although interactions between some epitopes were dependent on the presence of the V1, V2, and V3 loops. Enzymatic deglycosylation of the variable loop-deleted protein only minimally altered the binding of most antibodies examined. Thus, a carbohydrate-deficient, conserved HIV-1 gp120 core can be produced that has a structure closely approximating that of the full-length, correctly folded gp120 monomer.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp120 do Envelope de HIV/química , Proteína gp120 do Envelope de HIV/imunologia , HIV-1/imunologia , Sequência de Aminoácidos , Reações Antígeno-Anticorpo , Variação Antigênica , Sítios de Ligação de Anticorpos , Ligação Competitiva , Antígenos CD4/imunologia , Ensaio de Imunoadsorção Enzimática , Epitopos/imunologia , Glicosídeo Hidrolases , Glicosilação , Humanos , Dados de Sequência Molecular , Relação Estrutura-Atividade
20.
J Virol ; 72(3): 1876-85, 1998 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9499039

RESUMO

We have investigated whether the identity of the coreceptor (CCR5, CXCR4, or both) used by primary human immunodeficiency virus type 1 (HIV-1) isolates to enter CD4+ cells influences the sensitivity of these isolates to neutralization by monoclonal antibodies and CD4-based agents. Coreceptor usage was not an important determinant of neutralization titer for primary isolates in peripheral blood mononuclear cells. We also studied whether dualtropic primary isolates (able to use both CCR5 and CXCR4) were differentially sensitive to neutralization by the same antibodies when entering U87MG-CD4 cells stably expressing either CCR5 or CXCR4. Again, we found that the coreceptor used by a virus did not greatly affect its neutralization sensitivity. Similar results were obtained for CCR5- or CXCR4-expressing HOS cell lines engineered to express green fluorescent protein as a reporter of HIV-1 entry. Neutralizing antibodies are therefore unlikely to be the major selection pressure which drives the phenotypic evolution (change in coreceptor usage) of HIV-1 that can occur in vivo. In addition, the increase in neutralization sensitivity found when primary isolates adapt to growth in transformed cell lines in vitro has little to do with alterations in coreceptor usage.


Assuntos
Antígenos CD4/imunologia , Anticorpos Anti-HIV/imunologia , HIV-1/imunologia , Receptores CCR5/imunologia , Receptores CXCR4/imunologia , Adulto , Linhagem Celular Transformada , Criança , Proteínas de Fluorescência Verde , HIV-1/isolamento & purificação , Humanos , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Testes de Neutralização , Células Tumorais Cultivadas
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