Serial Passaging of Human-Simian Immunodeficiency Virus Clones Identifies Characteristics for Persistent Viral Replication.

We previously reported that a human immunodeficiency virus type 1 with a simian immunodeficiency virus substitution (HSIV-vif) could replicate in pigtailed macaques (PTMs), demonstrating that Vif is a species-specific tropism factor of primate lentiviruses. However, infections did not result in high-peak viremia or setpoint plasma viral loads, as observed during simian immunodeficiency virus (SIV) infection of PTMs. Here, we characterized variants isolated from one of the original infected animals with CD4 depletion after nearly 4years of infection to identify determinants of increased replication fitness.

Characterization of HIV-1 Nucleoside-Modified mRNA Vaccines in Rabbits and Rhesus Macaques.

Despite the enormous effort in the development of effective vaccines against HIV-1, no vaccine candidate has elicited broadly neutralizing antibodies in humans. Thus, generation of more effective anti-HIV vaccines is critically needed. Here we characterize the immune responses induced by nucleoside-modified and purified mRNA-lipid nanoparticle (mRNA-LNP) vaccines encoding the clade C transmitted/founder HIV-1 envelope (Env) 1086C.

Evidence for persistence of the SHIV reservoir early after MHC haploidentical hematopoietic stem cell transplantation.

Allogeneic transplantation (allo-HCT) has led to the cure of HIV in one individual, raising the question of whether transplantation can eradicate the HIV reservoir. To test this, we here present a model of allo-HCT in SHIV-infected, cART-suppressed nonhuman primates. We infect rhesus macaques with SHIV-1157ipd3N4, suppress them with cART, then transplant them using MHC-haploidentical allogeneic donors during continuous cART.

Intestinal damage precedes mucosal immune dysfunction in SIV infection.

HIV and pathogenic SIV infection are characterized by mucosal dysfunction including epithelial barrier damage, loss of Th17 cells, neutrophil infiltration, and microbial translocation with accompanying inflammation. However, it is unclear how and when these contributing factors occur relative to one another. In order to determine whether any of these features initiates the cycle of damage, we longitudinally evaluated the kinetics of mucosal and systemic T-cell activation, microbial translocation, and Th17 cell and neutrophil frequencies following intrarectal SIV infection of rhesus macaques.

Nucleoside-modified mRNA vaccines induce potent T follicular helper and germinal center B cell responses.

T follicular helper (Tfh) cells are required to develop germinal center (GC) responses and drive immunoglobulin class switch, affinity maturation, and long-term B cell memory. In this study, we characterize a recently developed vaccine platform, nucleoside-modified, purified mRNA encapsulated in lipid nanoparticles (mRNA-LNPs), that induces high levels of Tfh and GC B cells. Intradermal vaccination with nucleoside-modified mRNA-LNPs encoding various viral surface antigens elicited polyfunctional, antigen-specific, CD4 T cell responses and potent neutralizing antibody responses in mice and nonhuman primates.

Differential impact of transplantation on peripheral and tissue-associated viral reservoirs: Implications for HIV gene therapy.

Autologous transplantation and engraftment of HIV-resistant cells in sufficient numbers should recapitulate the functional cure of the Berlin Patient, with applicability to a greater number of infected individuals and with a superior safety profile. A robust preclinical model of suppressed HIV infection is critical in order to test such gene therapy-based cure strategies, both alone and in combination with other cure strategies. Here, we present a nonhuman primate (NHP) model of latent infection using simian/human immunodeficiency virus (SHIV) and combination antiretroviral therapy (cART) in pigtail macaques.

A spatio-temporal assessment of simian/human immunodeficiency virus (SHIV) evolution reveals a highly dynamic process within the host.

The process by which drug-resistant HIV-1 arises and spreads spatially within an infected individual is poorly understood. Studies have found variable results relating how HIV-1 in the blood differs from virus sampled in tissues, offering conflicting findings about whether HIV-1 throughout the body is homogeneously distributed. However, most of these studies sample only two compartments and few have data from multiple time points.

Loss of immune homeostasis dictates SHIV rebound after stem-cell transplantation.

The conditioning regimen used as part of the Berlin patient's hematopoietic cell transplant likely contributed to his eradication of HIV infection. We studied the impact of conditioning in simian-human immunodeficiency virus-infected (SHIV-infected) macaques suppressed by combination antiretroviral therapy (cART). The conditioning regimen resulted in a dramatic, but incomplete depletion of CD4 and CD8 T cells and CD20 B cells, increased T cell activation and exhaustion, and a significant loss of SHIV-specific Abs.

Design and In Vivo Characterization of Immunoconjugates Targeting HIV gp160.

Unlabelled: The envelope (Env) glycoprotein of HIV is expressed on the surface of productively infected cells and can be used as a target for cytotoxic immunoconjugates (ICs), in which cell-killing moieties, including toxins, drugs, or radionuclides, are chemically or genetically linked to monoclonal antibodies (MAbs) or other targeting ligands. Such ICs could be used to eliminate persistent reservoirs of HIV infection. We have found that MAbs which bind to the external loop of gp41, e.

Multilineage polyclonal engraftment of Cal-1 gene-modified cells and in vivo selection after SHIV infection in a nonhuman primate model of AIDS.

We have focused on gene therapy approaches to induce functional cure/remission of HIV-1 infection. Here, we evaluated the safety and efficacy of the clinical grade anti-HIV lentiviral vector, Cal-1, in pigtailed macaques (Macaca nemestrina). Cal-1 animals exhibit robust levels of gene marking in myeloid and lymphoid lineages without measurable adverse events, suggesting that Cal-1 transduction and autologous transplantation of hematopoietic stem cells are safe, and lead to long-term, multilineage engraftment following myeloablative conditioning.

Oral Immunization with Recombinant Vaccinia Virus Prime and Intramuscular Protein Boost Provides Protection against Intrarectal Simian-Human Immunodeficiency Virus Challenge in Macaques.

Human immunodeficiency virus type 1 (HIV-1) acquisition occurs predominantly through mucosal transmission. We hypothesized that greater mucosal immune responses and protective efficacy against mucosal HIV-1 infection may be achieved by prime-boost immunization at mucosal sites. We used a macaque model to determine the safety, immunogenicity, and protective efficacy of orally delivered, replication-competent but attenuated recombinant vaccinia viruses expressing full-length HIV-1 SF162 envelope (Env) or simian immunodeficiency virus (SIV) Gag-Pol proteins.

Lack of viral control and development of combination antiretroviral therapy escape mutations in macaques after bone marrow transplantation.

Objective: We have previously demonstrated robust control of simian/human immunodeficiency virus (SHIV1157-ipd3N4) viremia following administration of combination antiretroviral therapy (cART) in pigtailed macaques. Here, we sought to determine the safety of hematopoietic stem cell transplantation (HSCT) in cART-suppressed and unsuppressed animals.

Design: We compared disease progression in animals challenged with SHIV 100 days post-transplant, to controls that underwent transplant following SHIV challenge and stable cART-dependent viral suppression.

Lentivirus-mediated Gene Transfer in Hematopoietic Stem Cells Is Impaired in SHIV-infected, ART-treated Nonhuman Primates.

Recent studies have demonstrated that genetically modified hematopoietic stem cells (HSCs) can reduce HIV viremia. We have developed an HIV/AIDS-patient model in Simian/human immunodeficiency virus (SHIV)-infected pigtailed macaques that are stably suppressed on antiretroviral therapy (ART: raltegravir, emtricitabine and tenofovir). Following SHIV infection and ART, animals undergo autologous HSC transplantation (HSCT) with lentivirally transduced cluster of differentiation (CD)34(+) cells expressing the mC46 anti-HIV fusion protein.

Dysregulation of multiple inflammatory molecules in lymph node and ileum of macaques during RT-SHIV infection with or without antiretroviral therapy.

Background: Pathogenic infection with human immunodeficiency virus type 1 (HIV-1) or simian immunodeficiency virus (SIV) is characterized by a loss of CD4+ T cells and chronic lymphocyte activation even during suppressive antiretroviral therapy (ART).

Methods: Using NanoString, expression of >100 molecules associated with inflammation or immune activation was evaluated in mesenteric lymph nodes and ileum of macaques infected with a pathogenic SIV/HIV virus, RT-SHIV, during viremia or during suppressive ART and compared to uninfected controls.

Results: Of the 105 RNA species quantified in the tissues, expression of 33 genes was altered significantly in one or both tissues during viremia but returned to normal levels during ART.

Robust suppression of env-SHIV viremia in Macaca nemestrina by 3-drug ART is independent of timing of initiation during chronic infection.

Background: Nonhuman primates (NHPs) are an important model organism for studies of HIV pathogenesis and preclinical evaluation of anti-HIV therapies. The successful translation of NHP-derived data to clinically relevant anti-HIV studies will require better understanding of the viral strains and NHP species used and their responses to existing antiretroviral therapies (ART).

Methods: Five pigtailed macaques (Macaca nemestrina) were productively infected with the SIV/HIV chimeric virus SHIV-1157 ipd3N4 following intravenous challenge.

Expression of the memory marker CD45RO on helper T cells in macaques.

Background: In humans it has been reported that a major site of the latent reservoir of HIV is within CD4+ T cells expressing the memory marker CD45RO, defined by the mAb UCHL1. There are conflicting reports regarding the expression of this antigen in macaques, the most relevant animal species for studying HIV pathogenesis and testing new therapies. There is now a major effort to eradicate HIV reservoirs and cure the infection.

Positive selection of mC46-expressing CD4+ T cells and maintenance of virus specific immunity in a primate AIDS model.

Despite continued progress in the development of novel antiretroviral therapies, it has become increasingly evident that drug-based treatments will not lead to a functional or sterilizing cure for HIV(+) patients. In 2009, an HIV(+) patient was effectively cured of HIV following allogeneic transplantation of hematopoietic stem cells (HSCs) from a CCR5(-/-) donor. The utility of this approach, however, is severely limited because of the difficulty in finding matched donors.

Peripheral blood invariant natural killer T cells of pig-tailed macaques.

In humans, invariant natural killer T (iNKT) cells represent a small but significant population of peripheral blood mononuclear cells (PBMCs) with a high degree of variability. In this study, pursuant to our goal of identifying an appropriate non-human primate model suitable for pre-clinical glycolipid testing, we evaluated the percentage and function of iNKT cells in the peripheral blood of pig-tailed macaques. First, using a human CD1d-tetramer loaded with α-GalCer (α-GalCer-CD1d-Tet), we found that α-GalCer-CD1d-Tet(+) CD3(+) iNKT cells make up 0.

Dynamics of envelope evolution in clade C SHIV-infected pig-tailed macaques during disease progression analyzed by ultra-deep pyrosequencing.

Understanding the evolution of the human immunodeficiency virus type 1 (HIV-1) envelope during disease progression can provide tremendous insights for vaccine development, and simian-human immunodeficiency virus (SHIV) infection of non-human primate provides an ideal platform for such studies. A newly developed clade C SHIV, SHIV-1157ipd3N4, which was able to infect rhesus macaques, closely resembled primary HIV-1 in transmission and pathogenesis, was used to infect several pig-tailed macaques. One of the infected animals subsequently progressed to AIDS, whereas one remained a non-progressor.

Vaccination against heterologous R5 clade C SHIV: prevention of infection and correlates of protection.

A safe, efficacious vaccine is required to stop the AIDS pandemic. Disappointing results from the STEP trial implied a need to include humoral anti-HIV-1 responses, a notion supported by RV144 trial data even though correlates of protection are unknown. We vaccinated rhesus macaques with recombinant simian immunodeficiency virus (SIV) Gag-Pol particles, HIV-1 Tat and trimeric clade C (HIV-C) gp160, which induced cross-neutralizing antibodies (nAbs) and robust cellular immune responses.

Vif substitution enables persistent infection of pig-tailed macaques by human immunodeficiency virus type 1.

Among Old World monkeys, pig-tailed macaques (Pt) are uniquely susceptible to human immunodeficiency virus type 1 (HIV-1), although the infection does not persist. We demonstrate that the susceptibility of Pt T cells to HIV-1 infection is due to the absence of postentry inhibition by a TRIM5 isoform. Notably, substitution of the viral infectivity factor protein, Vif, with that from pathogenic SIVmne enabled replication of HIV-1 in Pt T cells in vitro.

Pathogenic infection of Macaca nemestrina with a CCR5-tropic subtype-C simian-human immunodeficiency virus.

Background: Although pig-tailed macaques (Macaca nemestrina) have been used in AIDS research for years, less is known about the early immunopathogenic events in this species, as compared to rhesus macaques (Macaca mulatta). Similarly, the events in early infection are well-characterized for simian immunodeficiency viruses (SIV), but less so for chimeric simian-human immunodeficiency viruses (SHIV), although the latter have been widely used in HIV vaccine studies. Here, we report the consequences of intrarectal infection with a CCR5-tropic clade C SHIV-1157ipd3N4 in pig-tailed macaques.

Differential pathogenicity of SHIV infection in pig-tailed and rhesus macaques.

Background: Differential pathogenicity has been observed in cynomolgus and rhesus macaques following primate lentivirus infection. However, little is known about the comparative susceptibility of pig-tailed macaques to lentivirus infection and diseases.

Methods: We compared the in vivo infectivity and pathogenicity of a CCR5-tropic SHIV(SF162 P4) after intravenous, intravaginal or intrarectal inoculation in rhesus and pig-tailed macaques.

Characterization of neutralizing antibody responses elicited by clade A envelope immunogens derived from early transmitted viruses.

The vast majority of studies with candidate immunogens based on the human immunodeficiency virus envelope (Env) have been conducted with Env proteins derived from clade B viruses isolated during chronic infection. Whether non-clade B Env protein immunogens will elicit antibodies with epitope specificities that are similar to those of antibodies elicited by clade B Envs and whether the antibodies elicited by Envs derived from early transmitted viruses will be similar to those elicited by Envs derived from viruses isolated during chronic infection are currently unknown. Here we performed immunizations with four clade A Envs, cloned directly from the peripheral blood of infected individuals during acute infection, which differed in lengths and extents of glycosylation.

Removal of a single N-linked glycan in human immunodeficiency virus type 1 gp120 results in an enhanced ability to induce neutralizing antibody responses.

Glycans on human immunodeficiency virus (HIV) envelope protein play an important role in infection and evasion from host immune responses. To examine the role of specific glycans, we introduced single or multiple mutations into potential N-linked glycosylation sites in hypervariable regions (V1 to V3) of the env gene of HIV type 1 (HIV-1) 89.6.