Principal Investigator:

Role of iNKT cells in chronic viral infection

Chronic viral infections associate with a progressive dysfunction of adaptive T cell immunity. Meanwhile, the markers and phenotypic features of exhausted T cells have been well described. In the framework of the currently ongoing project within the RTG 1949 we started to characterize the phenotype and function of invariant NKT cells (iNKT cells) in acute and chronic viral infection. iNKT cells share features of NK cells and T cells and bridge innate and adaptive immunity upon viral infection. iNKT cells are activated via cytokines such as IL-12, -15 and -18 or via its invariant TCR targeting glycolipids presented by the non-classical MHC class I molecule CD1d. iNKT cells can mediate direct effector functions against virus infected cells or promote adaptive immune responses by secretion of pro-inflammatory cytokines.

The T cell immune response to infection with HCV in high-risk groups of people who inject drugs (PWID) has been a research focus in the lab for several years. In the work on iNKT cells we could show that iNKT cells of PWID with chronic HCV infection have an activated phenotype as determined by increased expression of CD38 or CD69 compared to PWID with resolved infection. In line with this, patients with acute HCV infection who progressed to chronic hepatitis C also showed continuously increasing expression of CD38, whereas patients with spontaneously resolving acute hepatitis C showed declining CD38 expression on iNKT cells. Notably, this activated phenotype during chronic HCV infection did not translate into major functional differences between iNKT cells from PWID with chronic or resolved infection. However, it was noted that high CD38 expression on iNKT cells associates with reduced Interferon-gamma secretion, similar to exhausted T cells, although typical T cell exhaustion markers such as PD-1 or TIM-3 were not differentially expressed on invariant NKT cells.

In the future PhD project the functional and phenotypic differences between CD38 positive and CD38 negative human iNKT cells will be further characterized in detail. In ongoing experiments the transcriptome of activated iNKT cells with high CD38 expression versus resting iNKT cells with low CD38 expression is determined by RNA sequencing. Guided by the results of the transcriptome analysis, individual markers will be analyzed in patients with chronic hepatitis C versus patients with spontaneously resolved hepatitis C. For this purpose, large sample collections are available. As it is unclear if the “exhausted” phenotype of iNKT cells is reflected by CD38 upregulation upon cytokine activation, we will also perform single cell transcriptome analyses of iNKT cells from patients with chronic HCV infection compared to spontaneously resolved HCV infection. This will also help to dissect out in more detail, if iNKT cell subsets are differentially altered during chronic viral infection. Finally, in this project, the influence of HCMV infection on iNKT cells will also be studied. Infection with HCMV imprints the NK cell compartment by expansion of NKG2C positive NK cells and the T cell compartment by expansion of inflationary T cells with a terminally differentiated phenotype. It is unclear, if HCMV infection also shapes the iNKT cell repertoire and phenotype.

Publications

Thöns C, Senff T, Hydes TJ, Manser AR, Heinemann FM, Heinold A, Heilmann M,Kim AY, Uhrberg M, Scherbaum N, Lauer GM, Khakoo SI, Timm J. HLA-Bw4 80(T) and multiple HLA-Bw4 copies combined with KIR3DL1 associate with spontaneous clearance of HCV infection in people who inject drugs. J Hepatol. 2017 Apr 13.pii: S0168-8278(17)30213-1.

Thöns C, Berger C, Trippler M, Siemann H, Lutterbeck M, Broering R, Schlaak J, Heinemann FM, Heinold A, Nattermann J, Scherbaum N, Alter G, Timm J. KIR2DL3⁺NKG2A⁻ natural killer cells are associated with protection from productive hepatitis C virus infection in people who inject drugs. J Hepatol. 2014 Sep;61(3):475-81.

Ren G, Esser S, Jochum C, Schlaak JF, Gerken G, Schadendorf D, Dittmer U, Wu G, Yuan Z, Timm J. Interleukin 21 augments the hepatitis B virus-specific CD8+ T-cell response in vitro in patients coinfected with HIV-1. AIDS 2012;26:2145-53.

Ziegler S, Ruhl M, Tenckhoff H, Wiese M, Heinemann FM, Horn PA, Spengler U, Neumann-Haefelin C, Nattermann J, Timm J. Susceptibility to chronic hepatitis C virus infection is influenced by sequence differences in immunodominant CD8+ T cell epitopes. J Hepatol 2012;58:24-30.

Ruhl M, Knuschke T, Schewior K, Glavinic L, Neumann-Haefelin C, Chang DI, Klein M, Heinemann FM, Tenckhoff H, Wiese M, Horn PA, Viazov S, Spengler U, Roggendorf M, Scherbaum N, Nattermann J, Hoffmann D, Timm J. CD8+ T-cell response promotes evolution of hepatitis C virus nonstructural proteins. Gastroenterology 2011;140:2064-73.

Bengsch B, Seigel B, Ruhl M, Timm J, Kuntz M, Blum HE, Pircher H, Thimme R. Coexpression of PD-1, 2B4, CD160 and KLRG1 on exhausted HCV-specific CD8+ T cells is linked to antigen recognition and T cell differentiation. PLoS Pathog 2010;6:e1000947.

Neumann-Haefelin C, Timm J, Schmidt J, Kersting N, Fitzmaurice K, Oniangue-Ndza C, Kemper MN, Humphreys I, McKiernan S, Kelleher D, Lohmann V, Bowness P, Huzly D, Rosen HR, Kim AY, Lauer GM, Allen TM, Barnes E, Roggendorf M, Blum HE, Thimme R. Protective effect of human leukocyte antigen B27 in hepatitis C virus infection requires the presence of a genotype-specific immunodominant CD8+ T-cell epitope. Hepatology 2010;51:54-62.

Giugliano S, Oezkan F, Bedrejowski M, Kudla M, Reiser M, Viazov S, Scherbaum N, Roggendorf M, Timm J. Degree of cross-genotype reactivity of hepatitis C virus-specific CD8+ T cells directed against NS3. Hepatology 2009;50:707-16.

Neumann-Haefelin C, Timm J, Spangenberg HC, Wischniowski N, Nazarova N, Kersting N, Roggendorf M, Allen TM, Blum HE, Thimme R. Virological and immunological determinants of intrahepatic virus-specific CD8+ T-cell failure in chronic hepatitis C virus infection. Hepatology 2008;47:1824-36.

Kim AY, Schulze zur Wiesch J, Kuntzen T, Timm J, Kaufmann DE, Duncan JE, Jones AM, Wurcel AG, Davis BT, Gandhi RT, Robbins GK, Allen TM, Chung RT, Lauer GM, Walker BD. Impaired hepatitis C virus-specific T cell responses and recurrent hepatitis C virus in HIV coinfection. PLoS Med 2006;3:e492.