Biology subjects

Madelain, V.

Publications and source records attributed to Madelain, V..

3 recordsLinked to original sources

bioRxiv2023

Antiviral capacity of the early CD8 T-cell response is predictive of natural control of SIV infection

While most individuals suffer progressive disease following HIV infection, a small fraction spontaneously controls the infection. Although CD8 T-cells have been implicated in this natural control, their mechanistic roles are yet to be established. Here, we combined mathematical modeling and analysis of data from 16 SIV-infected macaques, of which 12 were natural controllers, to elucidate the role of CD8 T-cells in natural control. For each macaque, we considered, in addition to the canonical in vivo plasma viral load and SIV DNA data, longitudinal ex vivo measurements of the virus suppressive capacity of CD8 T-cells. Available mathematical models do not allow analysis of such combined in vivo-ex vivo datasets. By explicitly modeling the ex vivo assay and integrating it with in vivo dynamics, we developed a new framework that enabled the analysis. Our model fit the data well and estimated that the recruitment rate and/or maximal killing rate of CD8 T-cells was up to 2-fold higher in controllers than non-controllers (p=0.013). Importantly, the cumulative suppressive capacity of CD8 T-cells over the first 4-6 weeks of infection was associated with virus control (Spearmans {rho}=- 0.51; p=0.05). Thus, our analysis identified the early cumulative suppressive capacity of CD8 T-cells as a predictor of natural control. Furthermore, simulating a large virtual population, our model quantified the minimum capacity of this early CD8 T-cell response necessary for long-term control. Our study presents new, quantitative insights into the role of CD8 T-cells in the natural control of HIV infection and has implications for remission strategies.

microbiology↗

bioRxiv2020

Modeling SIV kinetics supports that cytotoxic response drives natural control and unravels heterogeneous populations of infected cells

SIVmac251-infected Mauritius cynomolgus macaques presenting a M6 MHC haplotype or challenged with a low inoculum dose by mucosal route are models for natural HIV control. Here we characterized by modeling the dynamics of plasma SIV-RNA and of SIV-DNA in blood cells of 16 macaques of the ANRS SIC study. SIV-RNA kinetics was best fitted using a model where the cytotoxic immune response progressively mounted up and reduced actively infected cells half-life (t1/2) from 5.5 days early on to about 0.3 days. The model predicted that the control was achieved in animals able to mount an effective immune response within three months, and this was corroborated by the longitudinal analysis of the CD8+ T-cell antiviral activity measured ex vivo. The control of SIV-RNA was accompanied in parallel by a slow and biphasic decline of SIV-DNA. This unravels the presence of at least two compartments of non-actively infected cells that are not rapidly eliminated by the immune system, one with a rapid turnover rate (t1/2=5.1 days) and predominant as long as SIV-RNA levels are still large, and one with a slow turnover (t1/2=118 days) consistent with the half-life of memory T-cells, and only visible when control is achieved. In summary, our analysis suggests that the establishment of an efficient CD8+ T-cell response in the first three months of the infection, and that progressively increases overtime is key to achieve SIV-RNA control in this model. Frequent SIV-DNA quantifications allowed identifying that most cells infected after viral peak have a short t1/2 but do not contribute significantly to viral production. One sentence summaryModeling viral dynamics in SIV natural controller macaques predicts that viral control is primarily driven by the capability to establish an efficient cytotoxic response and the viral decline during control unravels distinct compartments of infected cells.

microbiology↗

bioRxiv2019

Optimal maturation of the SIV-specific CD8+ T-cell response after primary infection is associated with natural control of SIV. ANRS SIC study

Highly efficient virus-specific CD8+ T-cells are associated with immune control of HIV infection, but it remains unclear how these cells are generated and maintained over time. We used a macaque model of spontaneous control of SIVmac251 infection to monitor the development and evolution of potent antiviral CD8+ T-cell responses. SIV-specific CD8+ T-cells emerged during primary infection in all animals. However, the ability of CD8+ T cells to suppress SIV replication was low in early stages but increased after a period of maturation, temporally linked with the establishment of sustained low-level viremia in controller macaques. SIV-specific CD8+ T-cells with a central memory phenotype expressed higher levels of survival markers in controllers versus non-controllers. In contrast, a persistently skewed differentiation phenotype was observed among central memory SIV-specific CD8+ T-cells in non-controllers since primary infection, typified by relatively high expression levels of T-bet. Collectively, these data show that the phenotype of SIV-specific CD8+ T-cells defined early after SIV infection favor the gain of antiviral potency as a function of time in controllers, whereas SIV-specific CD8+ T-cell responses in non-controllers fail to gain antiviral potency due to early defects imprinted in the central memory pool.

immunology↗