Differential expansion of T-cell receptor variable beta subsets after antigenic stimulation in patients with different outcomes of hepatitis C infection

Abstract

Persistent antigenic stimulation during chronic hepatitis C may alter the T-cell receptor variable chain beta (TCR BV) repertoire as well as the cytokine responses of hepatitis C virus (HCV)-specific T lymphocytes. We analysed the distribution of the TCR BV subsets 2.1, 3.1, 5.1, 6.1, 8, 13.1, 13.6, 14.1, 17.1, 21.3 in relation to intracytoplasmic expression of interleukin-2, interferon-gamma, interleukin-4 and interleukin-10. Using flow cytometry, CD45RO+ memory T cells of 27 patients with chronic hepatitis C, eight patients with resolved HCV infection and 16 non-HCV-related controls were studied with and without stimulation by the HCV core, NS3, NS4, NS5a and NS5b proteins. Patients with chronic and resolved hepatitis C differed by larger basal TCR BV2.1+, BV6.1+, BV17.1+ and BV21.3+ subsets in chronic hepatitis C, which were correlated to the numbers of T cells with spontaneous interleukin-2 and interferon-gamma production (r=0.51-0.73, P<0.05). Upon HCV-specific stimulation these subsets did not expand, whereas a marked in vitro expansion of TCR BV8+ T cells in response to all HCV proteins was selectively noted in chronic hepatitis C (P<0.05). This expansion of TCR BV8+ memory T cells was significantly correlated to HCV-induced interleukin-10 expression (r=0.58-0.98, P<0.01). Thus, differential involvement of selected TCR BV subsets may be related to the outcome of HCV infection.

Figure 1

Representative examples for the correlations between cytokine production and memory T-cell subsets. (a) The bivariate scatterplot shows the correlation of IL-2⁺ memory T cells with the fraction of the BV6.1⁺ T-cell subset Data are given as % positive CD45RO T cells. (b) The bivariate scatterplot shows the correlation of IFN-γ⁺ memory T cells with the fraction of the BV17.1⁺ T-cell subset. Data are given as % positive CD45RO T cells. (c) The bivariate scatterplot shows the correlation of IL-10⁺ memory T cells with the fraction of the BV8⁺ T-cell subset. Data are given as % positive CD45RO T cells. Data for other correlations are given in Table 3.

Figure 2

HCV-specific expansion of TCR BV8⁺ memory T cells. The scatterplots show the fraction of TCR BV8⁺ memory T cells after stimulation with recombinant HCV proteins (1 µg/ml) for 60 hr. Each dot represents the data from a single patient. The horizontal bar gives the mean of the group. Significant differences between the patient groups are indicated were appropriate.

Figure 3

Cytokine induction in the TCR BV8⁺ subset. Representative dot plot analysis of TCR BV8⁺ memory T cells for antigen-specific cytokine production in patient B.R. suffering from chronic hepatitis C after stimulation with recombinant NS5b (1 µg/ml) for 60 hr. Quadrant statistics were set on the basis of the isotype controls. The plots demonstrate that in chronic hepatitis C BV8⁺ memory T cells can produce both type 1 (IL-2, IFN-γ) and type 2 (IL-4, IL-10) cytokines in response to HCV antigens.