Biomedical subjects

Charles R Rinaldo

Publications and source records attributed to Charles R Rinaldo.

At least 19 recordsLinked to original sources

PubMed2007

Estimating the benefit of an HIV-1 vaccine that reduces viral load set point.

Vaccines designed to induce cell-mediated immune responses against human immunodeficiency virus (HIV)-1 are being developed. Such vaccines are unlikely to provide sterilizing immunity but may be associated with reduced viral set points after infection. We modeled the potential impact of a vaccine that reduces viral set point after infection, using natural history data from 311 HIV-1 seroconverters. Log-normal parametric regression models were used to estimate the log median time to events of interest. Relative times were estimated for those with viral load set points of 30,000 copies/mL (reference group) versus those with lower viral set points. The time to key clinical events in the course of HIV-1 disease progression was significantly extended for those with viral set points 0.5-1.25 log(10) copies/mL lower than the reference group. By quantifying the anticipated clinical benefits associated with a reduction in viral set point, these findings support the use of virologic end points in HIV-1 vaccine trials.

AIDS Vaccines↗

PubMed2006

CD27 and CD57 expression reveals atypical differentiation of human immunodeficiency virus type 1-specific memory CD8+ T cells.

The failure of human immunodeficiency virus type 1 (HIV-1)-specific CD8+ T cells to control chronic HIV-1 infection could be due to the progressive loss of their capacities to undergo normal memory effector differentiation. We characterized and compared the expressions of CD27, CD28, CD57, and CD62L by Epstein-Barr virus (EBV)-, cytomegalovirus (CMV)-, and HIV-1-specific CD8+ T cells by six-color, eight-parameter flow cytometry. In contrast to the maturation of EBV- and CMV-specific memory CD8+ T cells, we found that HIV-1-specific CD8+ T cells did not display coordinated down-regulation of CD27 and up-regulation of CD57 and accumulated in an atypical CD27(high) CD57(low) subset. Moreover, the accumulation of CD27(high) CD57(low) HIV-1-specific CD8+ T cells was positively correlated with HIV-1 plasma viremia. The differentiation of HIV-1-specific CD8+ T cells to an effector subset is therefore impaired during chronic HIV-1 infection. This lack of normal CD8+ T-cell differentiation could contribute to the failure of cellular immune control of HIV-1 infection.

Adult↗

PubMed2006

Development and implementation of a direct detection, quantitation and validation system for class I MHC self-peptide epitopes.

Gene and protein expression studies demonstrate that viral-infected and malignant cells undergo a complex series of transcriptional and translational changes. As class I MHC molecules reflect the proteome (and changes therein) by presenting intracellular peptide epitopes, the development of a direct discovery and validation technology for the identification of these epitopes is needed. We developed our technology using HIV-1-infected cells as a model. A combination of hollow fiber class I HLA protein production and mass spectrometric epitope analysis indicated a 3-fold increase in the host-peptide VLMTEDIKL(720-728), [eIF4G((720))] presented by the HLA-A*0201 of HIV-1-infected cells. This peptide is derived from the host-protein translation of eukaryotic initiation factor 4-gamma (eIF4G) that plays a pivotal role in cellular protein synthesis. Direct confirmation of expression of this self-encoded antigen was performed through development of a T cell receptor mimic (TCRm) monoclonal antibody (mAb). The resulting 4F7 TCRm demonstrated specific recognition of the eIF4G((720))-A*0201 complex. Staining of normal PBMCs with 4F7 showed only low levels of endogenous eIF4G((720)) presentation by HLA-A*0201, while 4F7 staining of HIV-1-infected PBMCs revealed an approximately 3-fold increase in eIF4G((720))-A*0201. The MHC-peptide complex was initially detectable by 4F7 at 3 days post-infection, with a steady increase through day 8. We therefore demonstrate the successful development and implementation of an integrated discovery and validation technology system for direct identification and confirmation of class I MHC-peptide epitopes on cells.

Antibodies, Monoclonal↗

PubMed2006

Diagnosis of human metapneumovirus infection in immunosuppressed lung transplant recipients and children evaluated for pertussis.

Human metapneumovirus (hMPV) is a recently discovered paramyxovirus that is known to cause respiratory tract infections in children and immunocompromised individuals. Given the difficulties of identifying hMPV by conventional culture, molecular techniques could improve the detection of this virus in clinical specimens. In this study, we developed a real-time reverse transcription-PCR (RT-PCR) assay designed to detect the four genetic lineages of hMPV. This assay and a commercial real-time nucleic acid sequence-based amplification (NASBA) assay (bioMérieux, Durham, NC) were used to determine the prevalence of hMPV in 114 immunosuppressed asymptomatic and symptomatic lung transplant recipients and 232 pediatric patients who were being evaluated for pertussis. hMPV was detected in 4.3% of the immunosuppressed lung transplant recipients and in 9.9% of children evaluated for pertussis. Both RT-PCR and NASBA assays were efficient in detection of hMPV infection in respiratory specimens. Even though hMPV was detected in a small number of the lung transplant recipients, it was still the most prevalent etiologic agent detected in patients with respiratory symptoms. In both of these diverse patient populations, hMPV infection was the most frequent viral respiratory tract infection identified. Given our findings, infection with hMPV infection should be determined as part of the differential diagnosis of respiratory illnesses.

Humans↗

PubMed2006

Impact of inversion of the CD4/CD8 ratio on the natural history of HIV-1 infection.

BACKGROUND: HIV-1 infection is characterized by an inverted CD4/CD8 T-cell ratio, but the distribution of inversions over time after seroconversion and whether delay of inversion is associated with a favorable prognosis are not known. METHODS: T-cell counts and clinical outcomes among men in the Multicenter AIDS Cohort Study who had incident HIV-1 infection before December 31, 1995 were analyzed by Kaplan-Meier and Cox proportional hazards methods. Results were also analyzed by time-dependent multivariate methods to adjust for CD4 lymphocyte counts, viral loads, age, race, and polymorphisms in host chemokine receptor genes (CCR5-Delta32 and CCR2-64I). RESULTS: Among 424 cases whose date of seroconversion was known to within +/-4.5 months, 317, 52, and 55 inverted their CD4/CD8 ratio within less than 1, 1 to 2, and more than 2 years of seroconversion, respectively. Longer time to inversion was significantly associated with longer time to AIDS, even after adjusting for CD4 lymphocyte count and viral load at the first seropositive visit and over the first 3 seropositive visits. Of the 6 seroconverters who had more than 500 CD4 lymphocytes 10 years after seroconversion without receiving highly active antiretroviral therapy, 5 took more than 2 years to invert their CD4/CD8 ratio. CONCLUSIONS: Time from HIV-1 seroconversion to inversion of the CD4/CD8 ratio independently predicted time to AIDS. Early measurements of the CD4/CD8 ratio until inversion occurs may identify people likely to become long-term nonprogressors or slow progressors, thus facilitating detailed studies of the mechanism of HIV-1 disease progression.

Adult↗

PubMed2006

Degeneracy and repertoire of the human HIV-1 Gag p17(77-85) CTL response.

CD8+ CTL responses are important for the control of HIV-1 infection. The immunodominant HLA-A2-restricted Gag epitope, SLYNTVATL (SL9), is considered to be a poor immunogen because reactivity to it is rare in acute infection despite its paradoxical dominance in patients with chronic infection. We have previously reported SL9 to be a help-independent epitope in that it primes highly activated CTLs ex vivo from CD8+ T cells of seronegative healthy donors. These CTLs produce sufficient cytokines for extended autocrine proliferation but are sensitive to activation-induced cell death, which may cause them to be eliminated by a proinflammatory cytokine storm. Here we identified an agonist variant of the SL9 peptide, p41 (SLYNTVAAL), by screening a large synthetic combinatorial nonapeptide library with ex vivo-primed SL9-specific T cells. p41 invariably immunized SL9-cross-reactive CTLs from other donors ex vivo and H-2Db beta2m double knockout mice expressing a chimeric HLA-A*0201/H2-Db MHC class I molecule. Parallel human T cell cultures showed p41-specific CTLs to be less fastidious than SL9-CTLs in the level of costimulation required from APCs and the need for exogenous IL-2 to proliferate (help dependent). TCR sequencing revealed that the same clonotype can develop into either help-independent or help-dependent CTLs depending on the peptide used to activate the precursor CD8+ T cells. Although Ag-experienced SL9-T cells from two patients were also sensitive to IL-2-mediated cell death upon restimulation in vitro, the loss of SL9 T cells was minimized with p41. This study suggests that agonist sequences can replace aberrantly immunogenic native epitopes for the rational design of vaccines targeting HIV-1.

Amino Acid Sequence↗

PubMed2006

Minimization of genetic distances by the consensus, ancestral, and center-of-tree (COT) sequences for HIV-1 variants within an infected individual and the design of reagents to test immune reactivity.

Eliciting maximal immune responses to highly divergent viruses is a challenge and a focus in AIDS vaccine development. Another challenge is to identify the immune correlates of protective immunity. Recent AIDS vaccine design approaches attempt to use reconstructed centralized viral sequences that minimize genetic differences to circulating viruses. Using these approaches, we derive and analyze consensus (CON), ancestral (ANC), and center-of-tree (COT) sequences to represent intra-individual HIV-1 env variants encoding a range of diversities and phylogenetic structures. Each reconstructed sequence significantly minimized genetic distances to extant sequences throughout the first 5 years of infection of an individual. Interestingly, ANC sequences diverged and were not significantly better than extant sequences in minimizing genetic distances at later stages of infection and disease, likely due to the development of a substantially asymmetric phylogeny. COT or CON sequences derived from autologous virus samplings may be useful for increasing the sensitivity of assessments of immune reactivity against HIV.

Amino Acid Sequence↗

PubMed2006

DC-SIGN is a receptor for human herpesvirus 8 on dendritic cells and macrophages.

Human herpesvirus 8 (HHV-8) causes Kaposi's sarcoma and pleural effusion lymphoma. In this study, we show that dendritic cell-specific ICAM-3 grabbing nonintegrin (DC-SIGN; CD209) is a receptor for HHV-8 infection of myeloid DCs and macrophages. DC-SIGN was required for virus attachment to these cells and DC-SIGN-expressing cell lines. HHV-8 binding and infection were blocked by anti-DC-SIGN mAb and soluble DC-SIGN, and mannan, a natural ligand for DC-SIGN. Infection of DCs and macrophages with HHV-8 led to production of viral proteins, with little production of viral DNA, similar to HHV-8 infection of vascular endothelial cells. Infection of DCs resulted in down-regulation of DC-SIGN, a decrease in endocytic activity, and an inhibition of Ag stimulation of CD8+ T cells. We propose that DC-SIGN serves as a portal for immune dysfunction and oncogenesis caused by HHV-8 infection.

Adult↗

PubMed2006

Repeat-region polymorphisms in the gene for the dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin-related molecule: effects on HIV-1 susceptibility.

In 1716 individuals--801 human immunodeficiency virus (HIV)-1-seropositive individuals, 217 high-risk HIV-1-seronegative individuals, and 698 general HIV-1-seronegative individuals--from a Seattle cohort and a Multicenter AIDS Cohort Study cohort, the association between HIV-1 susceptibility and repeat-region polymorphisms in the gene for the dendritic cell-specific intercellular adhesion molecule-3-grabbing nonintegrin-related molecule (DC-SIGNR) was investigated; 16 genotypes were found in the DC-SIGNR repeat region. The DC-SIGNR homozygous 7/7 repeat was found to be associated with an increased risk of HIV-1 infection (17.5% in high-risk HIV-1-seronegative individuals vs. 28.5% in HIV-1-seropositive individuals; P=.0015), whereas the DC-SIGNR heterozygous 7/5 repeat tended to be correlated with resistance to HIV-1 infection (35.5% in high-risk HIV-1-seronegative individuals vs. 27.6% in HIV-1-seropositive individuals; P=.0291). These findings suggest that DC-SIGNR polymorphisms may influence susceptibility to HIV-1.

Cell Adhesion Molecules↗

PubMed2006

Activation of HIV type 1 specific cytotoxic T lymphocytes from semen by HIV type 1 antigen-presenting dendritic cells and IL-12.

Seminal HIV-1-specific cytotoxic T lymphocytes (CTLs) could provide an important immune defense against local HIV-1 infection, and be important in impeding the spread of HIV-1 infection. In this study, we demonstrate that autologous blood-derived dendritic cells (DCs) loaded in vitro with synthetic HIV-1 peptides representing known CTL epitopes activated HLA class I restricted, anti-HIV-1 CTLs and interferon gamma responses in seminal CD8+ T cells from subjects with chronic HIV-1 infection on antiretroviral therapy. CTLs specific for the same HLA-restricted epitopes were detected in semen and blood of the same individuals by stimulation with peptide-loaded DCs. Anti-HIV-1 CTL responses from semen were enhanced by stimulation with DCs loaded with HIV-1 peptides and interleukin 12. Our results suggest that blood-derived DCs have HIV-1 antigen-presenting capacity for seminal CTL in HIV-1-infected subjects. The DC-T cell system can serve as a model for immunotherapy of HIV-1 infection in the local genital tract as well as systemic blood circulation.

Antigen-Presenting Cells↗

PubMed2006

DC-SIGN on B lymphocytes is required for transmission of HIV-1 to T lymphocytes.

Infection of T cells by HIV-1 can occur through binding of virus to dendritic cell (DC)-specific ICAM-3 grabbing nonintegrin (DC-SIGN) on dendritic cells and transfer of virus to CD4+ T cells. Here we show that a subset of B cells in the blood and tonsils of normal donors expressed DC-SIGN, and that this increased after stimulation in vitro with interleukin 4 and CD40 ligand, with enhanced expression of activation and co-stimulatory molecules CD23, CD58, CD80, and CD86, and CD22. The activated B cells captured and internalized X4 and R5 tropic strains of HIV-1, and mediated trans infection of T cells. Pretreatment of the B cells with anti-DC-SIGN monoclonal antibody blocked trans infection of T cells by both strains of HIV-1. These results indicate that DC-SIGN serves as a portal on B cells for HIV-1 infection of T cells in trans. Transmission of HIV-1 from B cells to T cells through this DC-SIGN pathway could be important in the pathogenesis of HIV-1 infection.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Effect of highly active antiretroviral therapy on multiple AIDS-defining illnesses among male HIV seroconverters.

The effect of highly active antiretroviral therapy (HAART) on multiple acquired immunodeficiency syndrome (AIDS)-defining illnesses remains unclear. Between 1984 and 2005, 573 male human immunodeficiency virus seroconverters in four US urban centers were followed for a median of 9.7 years. During follow-up, 345, 113, 50, and 65 men incurred 0, 1, 2, and >2 AIDS-defining illnesses, respectively. The authors extend the Cox proportional hazards model to determine whether the effect of HAART, as measured by calendar periods, persists beyond the first AIDS-defining illness. After adjustment for race and age at seroconversion, the hazards of a first through third AIDS-defining illness in the HAART calendar period (beyond July 1995) were 0.31 (95% confidence interval (CI): 0.21, 0.46), 0.39 (95% CI: 0.22, 0.74), and 0.33 (95% CI: 0.14, 0.79), respectively, relative to the monotherapy and combination therapy reference calendar period (January 1990-July 1995) and therefore did not attenuate with the number of prior AIDS-defining illnesses (p for homogeneity = 0.83). After the authors averaged over multiple AIDS-defining illnesses, the hazard of an AIDS-defining illness in the HAART calendar period was 0.34 (95% CI: 0.25, 0.45) relative to the reference calendar period. HAART protects against initial and subsequent AIDS-defining illnesses, whose inclusion in analysis markedly increased the precision of the estimated hazard ratio.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Human CD8+ T cells specific for influenza A virus M1 display broad expression of maturation-associated phenotypic markers and chemokine receptors.

To define the role of memory T cells in a non-persistent viral infection, we have delineated the phenotype of memory CD8+ T cells specific for influenza A virus (FluA; matrix protein M158-66) based on the expression of several memory/effector lineage markers and relevant chemokine receptors. We found a majority of FluA-specific CD8+ T cells expressed CD27 and CD28, and variably expressed CD45RA, CD62L, CD94 and granzyme A. A majority of FluA-specific CD8+ T cells expressed high levels of CXCR3, and moderate levels of CCR5 and CXCR4, whereas a limited proportion expressed CCR7, CCR6 and CXCR5. A phenotypic profile based on these observations showed that there are both immature and mature memory CD8+ T cells specific for FluA.

Adult↗

PubMed2005

Human immunodeficiency virus type 1 Vpr impairs dendritic cell maturation and T-cell activation: implications for viral immune escape.

Antigen presentation and T-cell activation are dynamic processes involving signaling molecules present in both APCs and T cells. Effective APC function and T-cell activation can be compromised by viral immune evasion strategies, including those of human immunodeficiency virus type 1 (HIV-1). In this study, we determined the effects of HIV-1 Vpr on one of the initial target of the virus, dendritic cells (DC), by investigating DC maturation, cytokine profiling, and CD8-specific T-cell stimulation function followed by a second signal. Vpr impaired the expression of CD80, CD83, and CD86 at the transcriptional level without altering normal cellular transcription. Cytokine profiling indicated that the presence of Vpr inhibited production of interleukin 12 (IL-12) and upregulated IL-10, whereas IL-6 and IL-1beta were unaltered. Furthermore, DC infected with HIV-1 vpr+ significantly reduced the activation of antigen-specific memory and recall cytotoxic-T-lymphocyte responses. Taken together, these results indicate that HIV-1 Vpr may in part be responsible for HIV-1 immune evasion by inhibiting the maturation of costimulatory molecules and cytokines essential for immune activation.

Antigens, CD↗

PubMed2005

Processing and presentation of exogenous HLA class I peptides by dendritic cells from human immunodeficiency virus type 1-infected persons.

Dendritic cells (DCs) loaded with viral peptides are a potential form of immunotherapy of human immunodeficiency virus type 1 (HIV-1) infection. We show that DCs derived from blood monocytes of subjects with chronic HIV-1 infection on combination antiretroviral drug therapy have increases in expression of HLA, T-cell coreceptor, and T-cell activation molecules in response to the DC maturation factor CD40L comparable to those from uninfected persons. Mature DCs (mDCs) loaded with HLA A*0201-restricted viral peptides of the optimal length (9-mer) were more efficient at activating antiviral CD8(+) T cells than were immature DCs or peptide alone. Optimal presentation of these exogenous peptides required uptake and vesicular trafficking and was comparable in DCs derived from HIV-1-infected and uninfected persons. Furthermore, DCs from HIV-1-infected and uninfected persons had similar capacities to process viral peptides with C-terminal and N-terminal extensions through their proteasomal and cytosolic pathways, respectively. We conclude that DCs derived from HIV-1-infected persons have similar abilities to process exogenous peptides for presentation to CD8(+) T cells as those from uninfected persons. This conclusion supports the use of DCs loaded with synthetic peptides in immunotherapy of HIV-1 infection.

Antigen Presentation↗

PubMed2005

Passive immunization against poliomyelitis: the Hammon gamma globulin field trials, 1951-1953.

Poliomyelitis has gone from being one of the worst scourges of the 20th century to nearing eradication in the 21st. This success is well known to be attributable to the Salk inactivated and Sabin attenuated poliovirus vaccines.However, before introduction of these vaccines, William McDowall Hammon of the University of Pittsburgh Graduate School of Public Health led the first major breakthrough in prevention of the disease by using passive immunization in one of the earliest double-blind, placebo-controlled clinical trials. This study provided the first evidence that antibodies to poliovirus could prevent the disease in humans.

Antibodies, Viral↗

PubMed2004

Lack of associations between HLA class II alleles and resistance to HIV-1 infection among white, non-Hispanic homosexual men.

HLA class II alleles were molecularly typed for 100 high-risk seronegative men and 184 low-risk seroconverters from the Multicenter AIDS Cohort Study (MACS). Seven resistant individuals homozygous for CCR5 Delta32 deletions were excluded from analysis. In the univariate analysis, no significant HLA class II associations with resistance/susceptibility to HIV type 1 infection were identified. However, the transporter associated with antigen presentation 2 (TAP2) Ala 665 variant associated with resistance in earlier analyses in the MACS was in linkage disequilibrium with some HLA class II alleles. After adjusting for the established associations with HLA-A*0205 subgroup and TAP2 Ala 665 variant, no HLA class II alleles were independently associated with resistance/susceptibility to HIV-1 infection. Other genetic factors in the HLA class II-TAP region of the major histocompatibility complex might be involved.

Alleles↗

PubMed2004

Virus infection of dendritic cells: portal for host invasion and host defense.

Dendritic cells (DCs) act as a portal for virus invasion and as the most potent antigen-presenting cells in antiviral host defense. Human immunodeficiency virus (HIV)-1 has served as the paradigm for virus interaction with DCs. HIV-1 infection of DCs via its primary CD4 receptor and secondary chemokine receptors leads to full virus replication (cis infection), whereas binding to C-type lectin receptors results both in cis replication, as well as transfer and replication of virus in CD4(pos) T cells (trans infection). DCs respond to this invasion by processing viral proteins through MHC class I and II pathways and undergoing a maturation that enhances their presentation of antigen to T cells for induction of adaptive antiviral immunity. HIV-1 and other viruses have evolved mechanisms to subvert this immune function. Engineering of DCs with various forms of viral immunogens and co-treatment with cytokines and chemokines is being used as an immunotherapy for HIV-1 and other viral infections.

Animals↗