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Conditionally-live attenuated SIV upregulates global T effector memory cell frequency under replication permissive conditions.

Manoussaka, MS; Berry, N; Ferguson, D; Stebbings, R; Robinson, M; Ham, C; Page, M; Li, B; Das, AT; Berkhout, B; et al. Manoussaka, MS; Berry, N; Ferguson, D; Stebbings, R; Robinson, M; Ham, C; Page, M; Li, B; Das, AT; Berkhout, B; Almond, N; Cranage, MP (2013) Conditionally-live attenuated SIV upregulates global T effector memory cell frequency under replication permissive conditions. Retrovirology, 10 (59). pp. 1-17. ISSN 1742-4690 https://doi.org/10.1186/1742-4690-10-59
SGUL Authors: Cranage, Martin Patrick Manoussaka, Maria

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Abstract

Background: Live attenuated SIV induces potent protection against superinfection with virulent virus; however the mechanism of this vaccine effect is poorly understood. Such knowledge is important for the development of clinically acceptable vaccine modalities against HIV. Results: Using a novel, doxycycline dependent, replication-competent live-attenuated SIVmac239Δnef (SIVrtTAΔnef), we show that under replication-permissive conditions SIV-rtTAΔnef is fully viable. Twelve rhesus macaques were infected with a peak plasma vRNA on average two log10 lower than in 6 macaques infected with unconditionally replication-competent SIVΔnef. Consistent with the attenuated phenotype of the viruses the majority of animals displayed low or undetectable levels of viraemia by 42-84 days after infection. Next, comparison of circulating T cells before and after chronic infection with parental SIVΔnef revealed a profound global polarisation toward CD28-CCR7- T-effector memory 2 (TEM2) cells within CD95+CD4+ and CD95+CD8+ populations. Critically, a similar effect was seen in the CD95+ CD4+ population and to somewhat lesser extent in the CD95+ CD8+ population of SIV-rtTAΔnef chronically infected macaques that were maintained on doxycycline, but was not seen in animals from which doxycycline had been withdrawn. The proportions of gut-homing T-central memory (TCM) and TEM defined by the expression of α4β7 and CD95 and differential expression of CD28 were increased in CD4 and CD8 cells under replication competent conditions and gut-homing CD4 TCM were also significantly increased under non-permissive conditions. TEM2 polarisation was seen in the small intestines of animals under replication permissive conditions but the effect was less pronounced than in the circulation. Intracellular cytokine staining of circulating SIV-specific T cells for IL-2, IFN-γ, TNF-α and IL-17 showed that the extent of polyfunctionality in CD4 and CD8 T cells was associated with replication permissivity; however, signature patterns of cytokine combinations were not distinguishable between groups of macaques. Conclusion: Taken together our results show that the global T memory cell compartment is profoundly skewed towards a mature effector phenotype by attenuated SIV. Results with the replication-conditional mutant suggest that maintenance of this effect, that may be important in vaccine design, might require persistence of replicating virus.

Item Type: Article
Additional Information: © 2013 Manoussaka et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Keywords: Science & Technology, Life Sciences & Biomedicine, Virology, Live attenuated SIV, T effector memory, Vaccine, SIMIAN IMMUNODEFICIENCY VIRUS, RHESUS MACAQUES, INFECTED MACAQUES, IN-VIVO, GASTROINTESTINAL-TRACT, PATHOGENIC SIVMAC239, VIRAL REPLICATION, VAGINAL CHALLENGE, IMMUNE-RESPONSES, HIV-INFECTION
SGUL Research Institute / Research Centre: Academic Structure > Infection and Immunity Research Institute (INII)
Journal or Publication Title: Retrovirology
ISSN: 1742-4690
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Dates:
DateEvent
5 June 2013Published
Web of Science ID: WOS:000321503600001
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URI: https://openaccess.sgul.ac.uk/id/eprint/102057
Publisher's version: https://doi.org/10.1186/1742-4690-10-59

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