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Vaccine-induced myeloid cell population dampens protective immunity to SIV.

ABSTRACT: Vaccines are largely evaluated for their ability to promote adaptive immunity, with little focus on the induction of negative immune regulators. Adjuvants facilitate and enhance vaccine-induced immune responses and have been explored for mediating protection against HIV. Using a regimen of peptide priming followed by a modified vaccinia Ankara (MVA) boost in a nonhuman primate model, we found that an SIV vaccine incorporating molecular adjuvants mediated partial protection against rectal SIVmac251 challenges. Animals treated with vaccine and multiple adjuvants exhibited a reduced viral load (VL) compared with those treated with vaccine only. Surprisingly, animals treated with adjuvant alone had reduced VLs that were comparable to or better than those of the vaccine-treated group. VL reduction was greatest in animals with the MHC class I allele Mamu-A*01 that were treated with adjuvant only and was largely dependent on CD8+ T cells. Early VLs correlated with Ki67+CCR5+CD4+ T cell frequency, while set-point VL was associated with expansion of a myeloid cell population that was phenotypically similar to myeloid-derived suppressor cells (MDSCs) and that suppressed T cell responses in vitro. MDSC expansion occurred in animals receiving vaccine and was not observed in the adjuvant-only group. Collectively, these results indicate that vaccine-induced MDSCs inhibit protective cellular immunity and suggest that preventing MDSC induction may be critical for effective AIDS vaccination.

SUBMITTER: Sui Y

PROVIDER: S-EPMC4038576 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature

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Vaccine-induced myeloid cell population dampens protective immunity to SIV.

Sui Yongjun Y Hogg Alison A Wang Yichuan Y Frey Blake B Yu Huifeng H Xia Zheng Z Venzon David D McKinnon Katherine K Smedley Jeremy J Gathuka Mercy M Klinman Dennis D Keele Brandon F BF Langermann Sol S Liu Linda L Franchini Genoveffa G Berzofsky Jay A JA

The Journal of clinical investigation 20140516 6

Vaccines are largely evaluated for their ability to promote adaptive immunity, with little focus on the induction of negative immune regulators. Adjuvants facilitate and enhance vaccine-induced immune responses and have been explored for mediating protection against HIV. Using a regimen of peptide priming followed by a modified vaccinia Ankara (MVA) boost in a nonhuman primate model, we found that an SIV vaccine incorporating molecular adjuvants mediated partial protection against rectal SIVmac2 ...[more]

PMID: 24837435

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Project description:Lassa fever (LF) is a rodent-borne viral disease that can be fatal for human beings. In this study, an attenuated Lassa vaccine candidate, ML29, was tested in SIV-infected rhesus macaques for its ability to elicit immune responses without instigating signs of virulent disease. ML29 is a reassortant between Lassa and Mopeia viruses that causes a transient infection in non-human primates and confers sterilizing protection from lethal Lassa viral challenge. However, since the LF endemic area of West Africa also has high HIV seroprevalence, it is important to determine whether vaccination could be safe in the context of AIDS. SIV-infected and uninfected rhesus macaques were vaccinated with the ML29 virus and monitored for classical and non-classical signs of arenavirus disease. Classical disease signs included viremia, rash, weight loss, high liver enzyme levels, and virus invasion of the central nervous system. Non-classical signs derived from profiling the blood transcriptome of virulent and non-virulent arenavirus infections included increased expression of interferon response genes and decreased expression of COX2, IL-1?, coagulation intermediates and nuclear receptors needed for stress signaling. Here it is demonstrated that SIV-infected and uninfected rhesus macaques responded similarly to ML29 vaccination, and that none developed signs of arenavirus disease or persistence. Furthermore, 5 of 5 animals given a heterologous challenge with a lethal dose of LCMV-WE survived without developing disease signs. 30 RNA samples from Monkey PBMC: 4 uninf. Monkey PBMC, 8 SIV-infected Monkey PBMC(From 8 Monkeys), 5 SIV+ML29-sc infected week1(Monkey PBMC), 5 SIV+ML29-sc infected week2(Monkey PBMC), 1 SIV+ML29-ig infected week1(Monkey PBMC), 1 SIV+ML29-ig infected week2(Monkey PBMC), 2 SIV+Arm-sc infected week1(Monkey PBMC), 2 SIV+Arm-sc infected week2(Monkey PBMC), 1 only ML29-iv infected week1(Monkey PBMC), 1 only ML29-iv infected week2(Monkey PBMC)

Project description:BackgroundT cells control viral infection, promote vaccine durability, and in coronavirus disease 2019 (COVID-19) associate with mild disease. We investigated whether prior measles-mumps-rubella (MMR) or tetanus-diphtheria-pertussis (Tdap) vaccination elicits cross-reactive T cells that mitigate COVID-19.MethodsAntigen-presenting cells (APC) loaded ex vivo with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), MMR, or Tdap antigens and autologous T cells from COVID-19-convalescent participants, uninfected individuals, and COVID-19 mRNA-vaccinated donors were co-cultured. T cell activation and phenotype were detected by interferon-γ (IFN-γ) enzyme-linked immunospot (ELISpot) assays and flow cytometry. ELISAs (enzyme-linked immunosorbant assays) and validation studies identified the APC-derived cytokine(s) driving T cell activation. TCR clonotyping and single-cell RNA sequencing (scRNA-seq) identified cross-reactive T cells and their transcriptional profile. A propensity-weighted analysis of COVID-19 patients estimated the effects of MMR and Tdap vaccination on COVID-19 outcomes.FindingsHigh correlation was observed between T cell responses to SARS-CoV-2 (spike-S1 and nucleocapsid) and MMR and Tdap proteins in COVID-19-convalescent and -vaccinated individuals. The overlapping T cell population contained an effector memory T cell subset (effector memory re-expressing CD45RA on T cells [TEMRA]) implicated in protective, anti-viral immunity, and their detection required APC-derived IL-15, known to sensitize T cells to activation. Cross-reactive TCR repertoires detected in antigen-experienced T cells recognizing SARS-CoV-2, MMR, and Tdap epitopes had TEMRA features. Indices of disease severity were reduced in MMR- or Tdap-vaccinated individuals by 32%-38% and 20%-23%, respectively, among COVID-19 patients.ConclusionsTdap and MMR memory T cells reactivated by SARS-CoV-2 may provide protection against severe COVID-19.FundingThis study was supported by a National Institutes of Health (R01HL065095, R01AI152522, R01NS097719) donation from Barbara and Amos Hostetter and the Chleck Foundation.

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Vaccine-induced myeloid cell population dampens protective immunity to SIV.

Publications

Vaccine-induced myeloid cell population dampens protective immunity to SIV.

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