ABSTRACT
BACKGROUND: Ustekinumab, a human immunoglobulin G1 monoclonal antibody that binds to and inhibits interleukin (IL)-12/IL-23, is indicated for multiple immune-mediated diseases. Ustekinumab is actively transported across the placenta and theoretically could impact pregnancy outcomes. Limited data on pregnancy outcomes with ustekinumab exposure are available. AIM: To assess pregnancy outcomes in patients exposed to ustekinumab during pregnancy METHODS: Cumulative data on medically confirmed ustekinumab-exposed pregnancies from the manufacturer's Global Safety Database were summarised. Descriptive data for pregnancy outcomes were presented overall and by patient subgroups. RESULTS: As of 31 August 2020, 408 medically confirmed, prospective, maternal ustekinumab-exposed pregnancies with reported outcomes were identified. The mean maternal age was 31 years. Of the 420 pregnancy outcomes (including 4 sets of twins),a , b 340 (81%) were live births, 51 (12.1%) spontaneous abortions, 25 (6%) elective/induced abortions, 3 (0.7%) stillbirths and 1 (0.2%) ongoing pregnancy with foetal congenital anomaly (CA). Among 340 live births, 33 (9.7%) were born pre-term. The rate of major CAs was similar by indication (Crohn's disease vs psoriasis), ustekinumab dose (45 mg vs 90 mg) and timing and duration of maternal exposure to ustekinumab. Prospective outcomes of pregnancies with paternal periconceptional ustekinumab exposure (n = 87) included 92% live births (1.2% major CA), 5.7% spontaneous abortions and 2.3% elective/induced abortions. CONCLUSIONS: Rates of adverse pregnancy outcomes or CAs with ustekinumab exposure were consistent with rates reported for the US general population and do not suggest a higher risk associated with maternal or paternal exposure to ustekinumab.
Subject(s)
Abortion, Spontaneous , Pregnancy Outcome , Abortion, Spontaneous/chemically induced , Abortion, Spontaneous/epidemiology , Adult , Female , Humans , Male , Maternal Exposure/adverse effects , Pregnancy , Pregnancy Outcome/epidemiology , Prospective Studies , Ustekinumab/adverse effectsABSTRACT
BACKGROUND AND AIMS: The UNIFI long-term extension [LTE] study reports the efficacy and safety of subcutaneous 90 mg ustekinumab through 3 years of maintenance therapy. METHODS: Patients randomised to ustekinumab every 12 weeks [q12w] or every 8 weeks [q8w] at maintenance baseline [N = 348] and randomised ustekinumab-treated patients in the LTE [N = 284] were evaluated. Symptomatic remission [Mayo stool frequency = 0/1, rectal bleeding = 0] was assessed. Safety included all LTE patients [N = 188 placebo and N = 457 ustekinumab]. RESULTS: Among patients randomised to the ustekinumab q12w and q8w groups at maintenance baseline, 54.1% and 56.3% achieved symptomatic remission at Week 152, respectively. Overall, 20% of patients discontinued ustekinumab, 10% of biologic-naïve and 30% of biologic-exposed patients. Among patients in symptomatic remission at Year 3, 94.6% and 98.0% of patients were also corticosteroid free, respectively. Corticosteroid-free symptomatic remission rates in the ustekinumab q12w and q8w groups were 51.2% and 55.1% at Week 152, respectively. Remission rates were higher for biologic-naïve patients than for those with a history of biologic failure. Biochemical evidence of response was demonstrated by stable, decreased C-reactive protein and faecal calprotectin measurements over 3 years. From Weeks 96 to 156, no deaths, major adverse cardiovascular events, or tuberculosis occurred. Nasopharyngitis, ulcerative colitis, and upper respiratory tract infection were most frequently reported. One ustekinumab-treated patient with a history of basal cell carcinoma [BCC] reported two BCCs. One patient in the q8w ustekinumab group, who was receiving concomitant 6-mercaptopurine, experienced serious adverse events of neutropenic sepsis and oral herpes. CONCLUSIONS: Efficacy of ustekinumab in patients with ulcerative colitis was confirmed through 3 years. No new safety signals were observed.
Subject(s)
Biological Products , Colitis, Ulcerative , Biological Products/therapeutic use , Colitis, Ulcerative/chemically induced , Colitis, Ulcerative/drug therapy , Humans , Remission Induction , Treatment Outcome , Ustekinumab/adverse effectsABSTRACT
The "Adacel (Tdap5) Pregnancy Registry" was used to identify 1182 women who received the tetanus, diphtheria, acellular pertussis [5 components] (Tdap5) vaccine during pregnancy from 2005 to 2016. To evaluate the safety and use of prenatal Tdap5, we calculated the rate of maternal, obstetrical, pregnancy and neonatal outcomes following Tdap5 pregnancy exposure and assessed vaccine uptake by year and trimester of exposure. The most commonly reported maternal adverse events included injection site reactions (2.6%; 95% Confidence Interval 1.8%, 3.7%), nervous system events (1.3%; 0.8%, 2.1%) and musculoskeletal events (1.1%; 0.6%, 1.9%). The most commonly reported complications of pregnancy were hypertension/preeclampsia (5.5%; 3.3%, 8.9%) and gestational diabetes (2.5%; 1.1%, 5.3%), while those for labor and delivery were premature labor (2.9%; 1.4%, 5.7%) and premature membrane rupture (1.5%; 0.4%, 3.8%). These rates were similar to, or lower than those reported for the general population of pregnant women. Among pregnancies with known birth outcomes (N = 275), 90.4% (86.2%, 93.4%) resulted in a live birth, 5.9% (3.6%, 9.5%) in spontaneous abortion, 3.0% (1.4%, 5.8%) in stillbirth, and 0.7% (0.0%, 2.8%) in ectopic pregnancies. Most newborns had normal APGAR scores and birth weights (98.1% and 93.0%, respectively), and only two reported a congenital anomaly (0.7%; 0.0%, 2.8%). An influx of reports in 2012 with third trimester Tdap5 exposure coincided with the 2012 updated Advisory Committee on Immunization Practices recommendations. This analysis did not identify any safety concerns across the continuum of maternal, obstetrical, pregnancy, and neonatal outcomes in women who received Tdap5 vaccination during pregnancy.
Subject(s)
Abortion, Spontaneous , Diphtheria-Tetanus-acellular Pertussis Vaccines , Diphtheria , Tetanus , Whooping Cough , Diphtheria/epidemiology , Diphtheria/prevention & control , Diphtheria-Tetanus-acellular Pertussis Vaccines/adverse effects , Female , Humans , Infant, Newborn , Male , Pertussis Vaccine , Pregnancy , Registries , Tetanus/prevention & control , Vaccination/adverse effects , Whooping Cough/epidemiology , Whooping Cough/prevention & controlABSTRACT
BACKGROUND: Ustekinumab is currently approved globally in Crohn's disease (CD) and psoriatic diseases. Recent phase 3 data demonstrate safety/efficacy in ulcerative colitis (UC). Crohn's disease and UC phase 3 programs had similar study designs, facilitating integrated safety analyses. METHODS: Data from 6 ustekinumab phase 2/3 CD and UC studies were pooled, and safety was evaluated through 1 year. Patients received 1 placebo or ustekinumab (generally 130 mg or ~6 mg/kg) intravenous induction, then subcutaneous (90 mg) maintenance every 8/12 weeks. Analyses incorporated all patients who received ≥1 ustekinumab dose. Safety outcomes are presented as percentages of patients (induction) and as number of patients with events per 100 patient-years of follow-up (through 1 year). For key safety events, 95% confidence intervals (CIs) are provided, as appropriate. Hazard ratios with 95% CIs from time-to-event analyses for serious adverse events and serious infections were also performed. RESULTS: Through 1 year, 2574 patients received ustekinumab (1733 patient-years of follow-up). The number of patients with adverse events per 100 patient-years (placebo 165.99 [95% CI, 155.81-176.67] vs ustekinumab 118.32 [95% CI, 113.25-123.55]), serious AEs (27.50 [95% CI, 23.45-32.04] vs 21.23 [95% CI, 19.12-23.51]), infections (80.31 [95% CI, 73.28-87.84] vs 64.32 [95% CI, 60.60-68.21]), serious infections (5.53 [95% CI, 3.81-7.77] vs 5.02 [95% CI, 4.02-6.19]), and malignancies excluding nonmelanoma skin cancer (0.17 [95% CI, 0.00-0.93] vs 0.40 [95% CI, 0.16-0.83]) were similar between placebo and ustekinumab. CONCLUSIONS: The safety profile of ustekinumab across the pooled inflammatory bowel disease population through 1 year was favorable and generally comparable to placebo. These data are consistent with the established safety profile of ustekinumab across indications. CLINICALTRIALS.GOV NUMBERS: NCT00265122; NCT00771667; NCT01369329; NCT01369342; NCT01369355; NCT02407236.
Subject(s)
Colitis, Ulcerative , Crohn Disease , Ustekinumab/therapeutic use , Colitis, Ulcerative/drug therapy , Crohn Disease/drug therapy , Humans , Remission Induction , Treatment Outcome , Ustekinumab/adverse effectsABSTRACT
BACKGROUND: The ongoing UNIFI long-term extension evaluates subcutaneous ustekinumab for moderate-to-severe ulcerative colitis (UC) from weeks 44 through 220. AIMS: To assess efficacy (through week 92) and safety (through week 96) during the long-term extension METHODS: Overall, 399 responders to intravenous ustekinumab induction and who were randomised to maintenance therapy were treated in the long-term extension (115 received subcutaneous placebo, 141 received ustekinumab 90 mg every 12 weeks [q12w], and 143 received ustekinumab 90 mg q8w). Placebo treatment was discontinued at unblinding after week 44. Partial Mayo scores were collected every 12 weeks and at each dosing visit after unblinding. Safety was evaluated throughout. RESULTS: Among all patients randomised in maintenance, symptomatic remission rates (stool frequency = 0/1; rectal bleeding = 0) at week 92 were, 64.5% and 67.6% in the ustekinumab q12w and q8w groups, respectively. Among randomised patients treated in the long-term extension, 78.7% and 83.2% of patients receiving q12w and q8w, respectively, attained symptomatic remission at week 92; >95% of patients in symptomatic remission at week 92 were corticosteroid-free. Both ustekinumab groups maintained efficacy through week 92. From weeks 44 to 96, adverse events (AEs) per hundred patient-years (PY) of follow-up for combined ustekinumab vs placebo were: 255.68 vs 267.93; serious AEs, 9.34 vs 12.69; malignancies (including non-melanoma skin cancers), 0.93 vs 1.49; and serious infections, 2.33 vs 2.99. One patient with multiple comorbidities who received one ustekinumab dose after dose adjusting from placebo experienced a fatal cardiac arrest. CONCLUSIONS: The efficacy of ustekinumab in patients with UC was sustained through 92 weeks. No new safety signals were observed (ClinicalTrials.gov number, NCT02407236).
Subject(s)
Colitis, Ulcerative/drug therapy , Ustekinumab/therapeutic use , Adult , Female , Humans , Maintenance Chemotherapy , Male , Middle Aged , Remission Induction , Treatment OutcomeABSTRACT
Acute SIVmac infection in macaques is accompanied by high levels of plasma viremia that decline with the appearance of viral immunity and is a model for acute HIV disease in man. Despite specific immune responses, the virus establishes a chronic, persistent infection. The destruction of CD4+ and CD4- lymphocyte subsets in macaques contributes to viral persistence and suggests the importance of mechanisms for depleting both infected and uninfected (bystander) cells. Bystander cell killing can occur when FasL binds the Fas receptor on activated lymphocytes, which include T and B cell subpopulations that are responding to the infection. Destruction of specific immune cells could be an important mechanism for blunting viral immunity and establishing persistent infection with chronic disease. We inhibited the Fas pathway in vivo with a monoclonal antibody against FasL (RNOK203). Here we show that treatment with anti-FasL reduced cell death in circulating T and B cells, increased CTL and antibody responses to viral proteins, and lowered the setpoint viremia. By blocking FasL during only the first few weeks after infection, we attenuated SIVmac disease and increased the life span for infected and treated macaques.
Subject(s)
Antibodies, Monoclonal/therapeutic use , Cytotoxicity, Immunologic/drug effects , Fas Ligand Protein/antagonists & inhibitors , Simian Acquired Immunodeficiency Syndrome/prevention & control , Animals , Antibodies, Viral/blood , Antibodies, Viral/immunology , Apoptosis/drug effects , B-Lymphocytes/drug effects , B-Lymphocytes/virology , Cytotoxicity Tests, Immunologic , Flow Cytometry , Humans , Macaca , Simian Acquired Immunodeficiency Syndrome/immunology , Simian Immunodeficiency Virus , T-Lymphocytes/drug effects , T-Lymphocytes/virology , Viral Proteins/immunology , Viremia/drug therapyABSTRACT
Extracellular human immunodeficiency virus-1 (HIV-1) Tat protein and Tat-derived peptides are biologically active but mechanisms of Tat processing are not known. Within the highly conserved basic region of HIV-1 Tat protein (amino acids, a.a. 48-56), we identified two putative furin cleavage sites and showed that Tat protein was cleaved in vitro at the second site, RQRR\ (a.a. 53-56\). This in vitro cleavage was blocked by a monoclonal antibody that binds near the cleavage site or by the furin inhibitor alpha-1 PDX. Monocytoid cells rich in furin also degraded Tat and this process was slowed by the furin inhibitor or the specific monoclonal antibody. Furin processing did not affect the rates for Tat uptake and nuclear accumulation in HeLa or Jurkat cells, but the transactivation activity was greatly reduced. Furin processing is a likely mechanism for inactivating extracellular HIV-1 Tat protein.
Subject(s)
Furin/chemistry , Gene Products, tat/chemistry , HIV-1/metabolism , Amino Acid Sequence , Antibodies, Monoclonal/chemistry , Binding Sites , Blotting, Western , Dose-Response Relationship, Drug , Furin/antagonists & inhibitors , HeLa Cells , Humans , Jurkat Cells , Molecular Sequence Data , Monocytes/metabolism , Monocytes/virology , Protein Binding , Protein Structure, Tertiary , Sequence Homology, Amino Acid , Transcriptional Activation , tat Gene Products, Human Immunodeficiency VirusABSTRACT
We constructed replication competent, attenuated, nef-deleted SHIV(89.6) that express the rhesus macaque chemokine genes MIP-1alpha, RANTES, or LTN from the nef region. The chemokine inserts were stable during several passages in CEMx174 cells and the viruses grew well in activated rhesus PBMC. Expression of virally encoded MIP-1alpha, RANTES, or LTN was detected in culture fluids from infected HOS CD4(+) CXCR4(+) cells, that were used because they have a low background production of these chemokines. The in vitro growth kinetics of all nef-deleted SHIV(89.6) were slower than the parental strain in both CEMx174 cells and rhesus PBMC. Rhesus macaques were susceptible to SHIV(89.6-MIP-1alpha), SHIV(89.6-RANTES), SHIV(89.6-LTN), and nef-deleted control SHIV(89.6-dLTN) infection via the intrarectal route using standard virus doses, and intact viruses were reisolated from infected animals throughout the interval of acute infection. SHIV expressing the chemokine genes MIP-1alpha, RANTES, or LTN may help determine the in vivo roles for these chemokines in modulating virus replication and disease.
Subject(s)
Chemokine CCL5/metabolism , Chemokines, C , HIV/genetics , Lymphokines/metabolism , Macrophage Inflammatory Proteins/metabolism , Sialoglycoproteins/metabolism , Simian Immunodeficiency Virus/genetics , Animals , Cell Line , Cells, Cultured , Chemokine CCL3 , Chemokine CCL4 , Chemokine CCL5/genetics , Cloning, Molecular , Gene Deletion , Gene Products, nef/genetics , HIV/metabolism , HIV/pathogenicity , HIV Infections/virology , Humans , Leukocytes, Mononuclear/virology , Lymphokines/genetics , Macaca mulatta , Macrophage Inflammatory Proteins/genetics , Recombination, Genetic , Sialoglycoproteins/genetics , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/metabolism , Simian Immunodeficiency Virus/pathogenicity , Virus Replication , nef Gene Products, Human Immunodeficiency VirusABSTRACT
HIV-1 vaccine candidates are designed to elicit Type 1 immune responses, including cytotoxic T cells and neutralizing antibodies. The type of immune response is influenced by many factors, including the levels of antigen expression and production of cytokines or chemokines; we designed a nonhuman primate study to evaluate the influence of these factors on protective immunity. Recombinant SHIV were engineered to express macrophage inflammatory protein-1 alpha (MIP-1alpha), regulated upon activation, normal T-cell expressed and secreted (RANTES), or Lymphotactin (Ltn) in place of nef in SHIV(89.6) (SHIV(89.6-MIP-1), SHIV(89.6-RANTES), SHIV(89.6-Ltn)). The parental virus SHIV(89.6) was included because it replicates to higher titer while still not causing disease. Control groups included animals that received a recombinant SHIV with a truncated chemokine construct (SHIV(89.6-dLtn)) and unvaccinated macaques. After pathogenic challenge with SHIV(89.6pd), animals from groups that received recombinant (nef-deleted) viruses had peak viremia levels three orders of magnitude lower than unvaccinated controls and increased survival times. Animals that received the original SHIV(89.6) (nef+) were highly resistant to both intrarectal and intravenous challenge with SHIV(89.6PD), and showed no signs of disease. There were no differences in survival times comparing unvaccinated and SHIV(89.6-dLtn) (control) groups, indicating that nef deleted viruses did not provide durable protection in this model. Strongest protection was seen in animals with the highest replicating virus (SHIV(89.6)), and the lower effect on survival after SHIV(89.6) nef-deleted vaccination, likely reflects differences in replication capacity. The protective effect of nef-deleted virus was partly restored by expressing Type 1 chemokines to augment viral immunity.
Subject(s)
AIDS Vaccines/immunology , Chemokines/metabolism , HIV Infections/immunology , Simian Acquired Immunodeficiency Syndrome/immunology , Viral Load , AIDS Vaccines/administration & dosage , AIDS Vaccines/genetics , Animals , Antibodies, Viral/blood , Chemokines/genetics , HIV Antibodies/blood , HIV Infections/mortality , HIV Infections/prevention & control , HIV Infections/virology , HIV-1/genetics , HIV-1/isolation & purification , HIV-1/pathogenicity , Humans , Macaca mulatta , Recombination, Genetic , Simian Acquired Immunodeficiency Syndrome/mortality , Simian Acquired Immunodeficiency Syndrome/prevention & control , Simian Acquired Immunodeficiency Syndrome/virology , Simian Immunodeficiency Virus/genetics , Simian Immunodeficiency Virus/isolation & purification , Simian Immunodeficiency Virus/pathogenicity , Vaccination , Vaccines, Attenuated , Virus ReplicationABSTRACT
The Yellow Fever Vaccine 17D (YFV17D) has been used as a vector for the Lassa virus glycoprotein precursor (LASV-GPC) resulting in construction of YFV17D/LASV-GPC recombinant virus. The virus was replication-competent and processed the LASV-GPC in cell cultures. The recombinant replicated poorly in guinea pigs but still elicited specific antibodies against LASV and YFV17D antigens. A single subcutaneous injection of the recombinant vaccine protected strain 13 guinea pigs against fatal Lassa Fever. This study demonstrates the potential to develop an YFV17D-based bivalent vaccine against two viruses that are endemic in the same area of Africa.
Subject(s)
Glycoproteins/metabolism , Lassa Fever/prevention & control , Lassa virus/metabolism , Vaccines, Synthetic , Yellow Fever Vaccine , Animals , Glycoproteins/genetics , Guinea Pigs , Humans , Lassa virus/genetics , Lassa virus/immunology , Vaccines, Synthetic/administration & dosage , Vaccines, Synthetic/genetics , Vaccines, Synthetic/metabolism , Viral Vaccines/administration & dosage , Viral Vaccines/genetics , Viral Vaccines/metabolism , Yellow Fever/prevention & control , Yellow Fever Vaccine/administration & dosage , Yellow Fever Vaccine/genetics , Yellow Fever Vaccine/metabolism , Yellow fever virus/immunologyABSTRACT
The human immunodeficiency virus Tat protein is essential for virus replication and is a candidate vaccine antigen. Macaques immunized with Tat or chemically modified Tat toxoid having the same clade B sequence developed strong antibody responses. We compared these antisera for their abilities to recognize diverse Tat sequences. An overlapping peptide array covering three clade B and two clade C Tat sequences was constructed to help identify reactive linear epitopes. Sera from Tat-immunized macaques were broadly cross-reactive with clade B and clade C sequences but recognized a clade B-specific epitope in the basic domain. Sera from Tat toxoid-immunized macaques had a more restricted pattern of recognition, reacting mainly with clade B and with only one clade B basic domain sequence, which included the rare amino acids RPPQ at positions 57 to 60. Monoclonal antibodies against the amino terminus or the domain RPPQ sequence blocked Tat uptake into T cells and neutralized Tat in a cell-based transactivation assay. Macaques immunized with Tat or Tat toxoid proteins varied in their responses to minor epitopes, but all developed a strong response to the amino terminus, and antisera were capable of neutralizing Tat in a transactivation assay.
Subject(s)
AIDS Vaccines/administration & dosage , AIDS Vaccines/immunology , Gene Products, tat/immunology , HIV Antibodies/blood , HIV Antibodies/immunology , Amino Acid Sequence , Animals , Antibodies, Monoclonal/biosynthesis , Gene Products, tat/administration & dosage , Gene Products, tat/chemistry , HIV Infections/prevention & control , HIV-1/immunology , HeLa Cells , Humans , Immunization , Jurkat Cells , Macaca , Mice , Mice, Inbred BALB C , Molecular Sequence Data , Neutralization Tests , Peptides/chemical synthesis , Peptides/chemistry , Peptides/immunology , Transcriptional Activation , tat Gene Products, Human Immunodeficiency VirusABSTRACT
Lymphocytic choriomeningitis virus (LCMV) and Lassa virus can cause hemorrhagic fever and liver disease in primates. The WE strain of LCMV (LCMV-WE) causes a fatal Lassa fever-like disease in rhesus macaques and provides a model for arenavirus pathogenesis in humans. LCMV-WE delivered intravenously or intragastrically to rhesus macaques targets hepatocytes and induces high levels of liver enzymes, interleukin-6 (IL-6), soluble IL-6 receptor (sIL-6R), and soluble tumor necrosis factor receptors (sTNFRI and -II) in plasma during acute infection. Proinflammatory cytokines TNF-alpha and IL-1beta were not detected in plasma of infected animals, but increased plasma gamma interferon was noted in fatally infected animals. Immunohistochemistry of acute liver biopsies revealed that 25 to 40% of nuclei were positive for proliferation antigen Ki-67. The increases in IL-6, sIL-6R, sTNFR, and proliferation antigen that we observe are similar to the profile of incipient liver regeneration after surgical or toxic injury (N. Fausto, Am. J. Physiol. 277:G917-G921, 1999). Although IL-6 was not directly induced by virus infection in vitro, peripheral blood mononuclear cells from acutely infected monkeys produced higher levels of IL-6 upon lipopolysaccharide stimulation than did healthy controls. Our data confirm that acute infection is associated with weak inflammatory responses in tissues and initiates a program of liver regeneration in primates.
Subject(s)
Arenaviridae Infections/immunology , Arenaviridae Infections/pathology , Hepatocytes/pathology , Interleukin-6/biosynthesis , Lymphocytic choriomeningitis virus , Alanine Transaminase/blood , Animals , Cell Division , Chlorocebus aethiops , Hepatocytes/virology , Interleukin-6/blood , Interleukin-8/biosynthesis , Ki-67 Antigen/analysis , Macaca mulatta , Receptors, Interleukin-6/blood , Receptors, Tumor Necrosis Factor/blood , Tumor Necrosis Factor-alpha/biosynthesis , Vero CellsABSTRACT
The human immunodeficiency virus (HIV) Tat protein has a critical role in viral transcription, but this study focuses on its additional role as an extracellular effector of lymphocyte cell death. It is well known that Tat induces tumor necrosis factor-related apoptosis-induced ligand (TRAIL) in peripheral blood mononuclear cells (PBMC), and we show that the majority of TRAIL is produced by the monocyte subset of PBMC. Human monocytes and U937 monoblastoid cells did not take up soluble HIV Tat-86, as T cells did, yet produced more TRAIL than did T cells. TRAIL secretion was induced by Tat and by a cysteine-rich peptide of Tat but not by sulfhydryl-modified Tat toxoid. Although there was only a slight increase in cell surface expression of TRAIL on monocytes, sufficient TRAIL was secreted to be toxic for T cells. The cytotoxicity of Tat-stimulated monocyte medium could be blocked by a TRAIL-neutralizing antibody. T cells treated with Tat did not secrete enough TRAIL to mediate cell death in our assay. Remarkably, uninfected T cells are more susceptible to TRAIL than are HIV-infected T cells. The production of TRAIL by Tat-stimulated monocytes provides a mechanism by which HIV infection can destroy uninfected bystander cells.
Subject(s)
Apoptosis , CD4-Positive T-Lymphocytes/physiology , Gene Products, tat/metabolism , HIV-1 , Membrane Glycoproteins/metabolism , Monocytes/drug effects , Tumor Necrosis Factor-alpha/metabolism , Apoptosis Regulatory Proteins , CD4-Positive T-Lymphocytes/virology , Gene Products, tat/pharmacology , HIV-1/physiology , Humans , Jurkat Cells , Membrane Glycoproteins/drug effects , Monocytes/metabolism , TNF-Related Apoptosis-Inducing Ligand , Tumor Necrosis Factor-alpha/drug effects , U937 Cells , Up-Regulation , tat Gene Products, Human Immunodeficiency VirusABSTRACT
Arenaviruses are transmitted from rodents to human beings by blood or mucosal exposure. The most devastating arenavirus in terms of human disease is Lassa fever virus, causing up to 300,000 annual infections in West Africa. We used a model for Lassa fever in which Rhesus macaques were infected with a related virus, lymphocytic choriomeningitis virus (LCMV). Our goals were to determine the outcome of infection after mucosal inoculation and later lethal challenge, to characterize protective immune responses, and to test cross-protection between a virulent (LCMV-WE) and an avirulent (LCMV-ARM) strain of virus. Although intravenous infections in the monkey model were uniformly lethal, intragastric infections recapitulated the spectrum of clinical outcomes seen in human exposure to Lassa fever virus: death, recovery from disease, and most often, subclinical infection. Plaque neutralization, ELISA, lymphocyte proliferation, and chromium-release assays were used to monitor humoral and cellular immune responses. Cross protection between the two strains was observed. The three out of seven monkeys that experienced protection were also the three with the strongest cell-mediated immunity.
Subject(s)
Arenaviridae Infections/immunology , Gastric Mucosa/virology , Lymphocytic choriomeningitis virus/immunology , Lymphocytic choriomeningitis virus/pathogenicity , Animals , Antibodies, Viral/blood , Antibodies, Viral/immunology , Arenaviridae Infections/virology , Cell Death , Cross Reactions , Cytotoxicity, Immunologic , Enzymes/blood , Female , Leukocytes, Mononuclear/immunology , Leukocytes, Mononuclear/physiology , Lymphocyte Activation , Macaca mulatta , Neutralization Tests , RNA, Viral/blood , Viremia , VirulenceABSTRACT
Tat is among the required regulatory genes of human immunodeficiency virus type 1 (HIV-1). Tat functions both within infected cells as a transcription factor and as an extracellular factor that binds and alters bystander cells. Some functions of extracellular Tat can be neutralized by immune serum or monoclonal antibodies. In order to understand the antibody response to Tat, we are defining antibody epitopes and the effects of natural Tat sequence variation on antibody recognition. The dominant Tat epitope in macaque sera is within the first 15 amino acids of the protein amino terminus. Together with a subdominant response to amino acids 57 to 60, these two regions account for most of the macaque response to linear Tat epitopes and both regions are also sites for the binding of neutralizing antibodies. However, the dominant and subdominant epitope sequences differ among virus strains, and this natural variation can preclude antibody binding and Tat neutralization. We also examined serum samples from 31 HIV-positive individuals that contained Tat binding antibodies; 23 of the 31 sera recognized the amino terminus peptide. Similar to binding in macaques, human antibody binding to the amino terminus was affected by variations at positions 7 and 12, sequences that are distinct for clade B compared to other viral clades. Tat-neutralizing antibodies to the dominant amino terminus epitope are affected by HIV clade variation.