ISSN:0889-2229    

DOI:10.1089/aid.1997.13.1

年代:1997

数据来源: MAL

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.5

年代:1997

数据来源: MAL

摘要:

Neutralizing antibody (NA) patterns in the sera of individuals naturally infected with human immunodeficiency virus (HIV) type 1, HIV-2, and the simian immunodeficiency virus (SIVcpz) to their homologous and heterologous isolates were determined in a peripheral blood mononuclear cell-based neutralization assay. We examined the role of the V3 loop of HIV-1 and SIVcpz in neutralization and the cross-reactivities among them. Cross-neutralization by sera of humans and chimpanzees naturally infected, respectively, with HIV-1 and SIVcpz isolates was more extensive than the infrequent and low-titer cross-neutralizations observed between HIV-1 and HIV-2. Neutralization of 9 of the 16 HIV-1 isolates by 9 of 10 HIV-2 and all 3 SIVcpz antibody-positive sera were weak and sporadic (titer, 1:10–1:160. Twelve of 15 HIV-1 sera neutralized the 2 SIVcpz isolates with titers of 1:10–1:320 but only sporadically neutralized the 6 HIV-2 isolates (titers: 1:10–1:20). The majority of HIV-1 and SIVcpz sera bound to the V3 peptides although their binding capacity did not readily reflect their neutralizing capacity. The HIV-2 sera did not or only weakly bound to the V3 peptides. These results suggest that HIV-1 and SIVcpz share some structural and functional similarities that set them apart from

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.7

年代:1997

数据来源: MAL

摘要:

Various studies have reported that primary human immunodeficiency viruses seem to be more refractory to neutralization by HIV-positive sera than T cell line-adapted strains. In this study we also show that adaptation of the HIV-1SF-2strain, produced in PBMCs, to the cell line CEM-SS renders this isolate sensitive to neutralization by almost all the sera tested. Further neutralization studies should thus focus on the development of an assay involving primary isolates in order to detect antibodies having a neutralizing activityin vivo. Neutralization protocols currently use either an antibody end-point dilution assay, which combines a fixed inoculum of virus with serial dilutions of antibody, or an infectivity reduction assay, which uses serial dilutions of virus with a single dilution of antibody. We have developed an assay designed for studying the neutralization of primary isolates that combines these two approaches. Performing the assay on PBMCs allows all primary isolates to be analyzed, not just those multiplying in T cell lines. The neutralizing titer measured on PBMCs for human HIV-positive sera is low, but reproducible and independent of the virus titer in a given experiment. It can be increased about five-fold by changing the temperature and duration of virus-serum interaction (overnight at 4°C instead of 1 hr at 37°C). These results emphasize the need for a relevant neutralization assay involving primary isolates and primary cells for a better understanding of the role of humoral response in HIV infectio

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.19

年代:1997

数据来源: MAL

摘要:

Twenty-four HIV-seronegative men, at high risk of HIV infection, were recruited into a phase I/II safety and immunogenicity trial of a prototype HIV vaccine. The immunogen was a synthetic, monovalent, octameric HIV-1MNV3 peptide in an aluminum hydroxide (alum) adjuvant. The vaccine had been evaluated previously using a standard 0-, 1-, 6-month intramuscular schedule and was found to stimulate neutralizing antibody in 60-90% of volunteers. Participants were randomized to receive either 500 μg (n= 10; high dose) or 100 μg (n= 10; low dose) of immunogen or placebo (alum alone;n= 4) at 0, 1, and 6 months by subcutaneous injection. Responses to the immunogen were evaluated by enzyme-linked immunosorbent assay (ELISA)-detectable antibody and by proliferative responses. Safety was monitored by both clinical assessment and regular review with a clinical psychologist. No serious adverse experiences were observed following administration of the assigned medication. One individual (placebo) seroconverted while on study, following exposure to HIV. After the vaccination course only four individuals (three high dose and one low dose) had ELISA-detectable antibody against the immunogen. In the evaluable samples, from 19 volunteers, only 7 vaccine recipients (3 high dose and 4 low dose) had demonstrable lymphoproliferative responses to preparations of the immunogen. Subcutaneous administration of this candidate vaccine was safe but did not result in uniform or robust immunological response

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.29

年代:1997

数据来源: MAL

摘要:

The potential benefit of T cell-based vaccination for HIV-1 infection remains to be determined. Cytotoxic T lymphocytes (CTLs) appear to clear substantial populations of HIV-1 virusin vivo, although CTL activity may contribute to the decline in CD4+T cell count observed in the course of disease. To investigate further the role of specific CTL responses in the control of HIV-1 replication, we raised primary CTL lines against a panel of conserved HIV-1 epitopes using blood-derived dendritic cells as antigen-presenting cells (APCs). Specific primary human CTL responses were induced against HLA-A*0201-restricted peptides with dendritic cells from HIV-1-seronegative donors. This method of immunization elicited cytotoxic activities capable of recognizing endogenously processed antigen. The CTL induction protocol was extended in order to explore the capacity of HLA-matched allogeneic dendritic cells to evoke novel CTL responses in T cells from an HIV-seropositive asymptomatic individual. Allogeneic peptide-pulsed dendritic cells from a healthy sibling were capable of eliciting a CTL response directed against an HIV epitope (env814: SLLNATDIAV) that was initially not detected in the CTL effector population of the HIV-1-infected patient. The possibility of manipulating CTL specificity directed against multiple conserved HIV-1 epitopes represents a significant step in the evaluation of T cell-based vaccination for treatment of disease.

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.33

年代:1997

数据来源: MAL

摘要:

We have developed a comparative study of antigenic and immunogenic properties of selected immunodominant HIV-1 epitopes from p24 and gp120 proteins added to C-terminally truncated hepatitis B virus (HBV) core protein and exposed on the surface of chimeric core particles. Inserted p24 (121-210) and gp120/MN (306-328) epitopes induced the appropriate humoral and cellular immune responses against HIV-1. Superficially exposed region 160-192 of p24 also showed maximal B cell immunogenicity whereas buried region 148-162 induced maximal T cell response. Both recombinant proteins were also able to be recognizedin vitroby T lymphocytes of HIV-1 asymptomatic carriers.

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.41

年代:1997

数据来源: MAL

摘要:

The effectiveness of the poliovirus vaccines to induce both systemic and mucosal immunity has prompted the development of this virus as a vector in which to express foreign proteins. Our laboratory has previously reported on the construction and characterization of poliovirus genomes that encode HIV-1 proteins (Porter DC,et al.: J Virol 1996;70:2643-2649). To develop this system further, we have constructed poliovirus genomes, referred to as replicons, which encode the SIVmac239 Gag or Env SU in place of the poliovirus capsid gene (P1). Since the replicons do not encode capsid proteins, they are encapsidated into poliovirions by passage with a recombinant vaccinia virus, VVP1, which provides the poliovirus capsid proteinsin trans. Using this system, we have derived stocks of the encapsidated replicons which encode the SIVmac239 Gag or Env SU protein. Infection of cells with the replicon that encodes SIVmac239 Gag resulted in the expression of a 55-kDa protein that was released from the infected cells. Analysis of the sedimentation of the released proteins by sucrose density gradient centrifugation revealed that the protein was released from the cell in the form of a virus-like particle. Infection of cells with the replicons encoding the SIVmac239 Env SU resulted in the expression of a 63-kDa protein, corresponding to the molecular mass predicted for the nonglycosylated SIVmac239 SU protein. A second protein with a molecular mass greater than 160 kDa was also immunoprecipitated. After enzymatic deglycosylation, this protein migrated at a molecular mass consistent with that for an Env SU dimer. Analysis of the medium from cells infected with the replicon encoding SIVmac239 Env SU revealed the presence of a protein of molecular mass 85-90 kDa, possibly representing a fragment of the SIVmac239 Env SU protein. To determine the immunogenicity of the replicons encoding SIVmac239 Gag or Env SU, transgenic mice that express the human receptor for poliovirus, and are thus susceptible to poliovirus, were immunized via the intramuscular route. A serum antibody response to SIV envelope was detected following booster immunization, establishing that the encapsidated replicon was immunogenic. Finally, we demonstrate that the replicons have the capacity to infect peripheral blood mononuclear monocytes/macrophages, suggesting that this cell is a possible target forin vivoinfection. The results of our studies, then, lend further support for the development and application of recombinant poliovirus replicons in a vaccine strategy.

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.53

年代:1997

数据来源: MAL

摘要:

Chemokines were originally characterized by their ability to direct migration and induce activation of selected leukocyte populations. The β-chemokines MIP-1α, MIP-β, and RANTES have been implicated in the suppression of viral replication by CD8+T cells from HIV-infected individuals. The present study was undertaken to evaluate the effect of β-chemokines on HIV replication in cocultures of dendritic cells (DCs) and CD4+T cells, anin vitromodel of the lymphoid microenvironment. In the acute infection system, where DCs from uninfected individuals are pulsed with HIV and cocultured with autologous CD4+T cells, no inhibition of replication of monocytotropic or T cell tropic viral isolates by MIP-1α, MIP-1β, and RANTES, alone or in combination, was observed. In contrast, in an endogenous infection system, where the DCs and CD4+T cells were obtained from HIV-infected subjects, addition of recombinant β-chemokines suppressed HIV replication. However, neutralizing antibodies to β-chemokines did not affect the suppressive activity of CD8+T cells from HIV-infected donors in either system, suggesting that CD8+T cell-mediated suppression is not due exclusively to β-chemokines. Furthermore, no significant differences in secretion of MIP-1α, MIP-1β, and RANTES by purified CD8+T cells were noted in uninfected versus HIV-infected donors, regardless of the stage of disease. These results indicate that HIV suppression by CD8+T cells derived from HIV-infected donors is a multifactorial phenomenon and not limited to the action of MIP-1α, MIP-1β

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.63

年代:1997

数据来源: MAL

摘要:

CD8+T lymphocytes of HIV-1-infected individuals can efficiently suppress HIV-1 replication in CD4+T lymphocytes via soluble factors. We compared the effect of CD8+T cell-derived supernatants on HIV-1 LTR-driven gene expression in T cells and monocytic cell lines. Our results demonstrate that CD8+T cell supernatants that suppressed HIV-1 LTR-driven gene expression in Jurkat T cells significantly enhanced expression in Tat-activated U38 monocytic cells in the presence and absence of mitogenic stimulation. Examination of a panel of CD8+T cell-derived supernatants from HIV-infected individuals demonstrated that the extent of enhancement of transcription in U38 cells was mirrored in most cases by a similar level of suppression of transcription in Jurkat T cells. In latently infected U1 cells treated with TNF-α, culture with CD8+T cell supernatants markedly enhanced virus production. In addition, the percentage increase in the enhancement of HIV-1 LTR-driven CAT expression by CD8+T cell supernatants correlated strongly (r= 0.911) with the level of p24 detected. The level of LTR-mediated gene expression in U38 cells was not influenced by rhMIP-1α rhMIP-1β, or rhRANTES over a wide range of chemokine concentration. Treatment of CD8+T cell supernatant with a combination of antibodies to these chemokines resulted in a further augmentation of LTR-mediated CAT expression in U38 cells. Taken together, these results demonstrate that CD8+T cell suppressive factors may have opposite effects on HIV-1 LTR-driven gene expression and replication dependent on target cell type and further suggest that the β-chemokines do not influence HIV-1 LTR-mediated gene expression in monocytic ce

ISSN:0889-2229    

DOI:10.1089/aid.1997.13.71

年代:1997

数据来源: MAL