Antibody Repertoire Analysis of Hepatitis C Virus Infections Identifies Immune Signatures Associated With Spontaneous Clearance.

Hepatitis C virus (HCV) is a major public health concern, with over 70 million people infected worldwide, who are at risk for developing life-threatening liver disease. No vaccine is available, and immunity against the virus is not well-understood. Following the acute stage, HCV usually causes chronic infections. However, ~30% of infected individuals spontaneously clear the virus. Therefore, using HCV as a model for comparing immune responses between spontaneous clearer (SC) and chronically infected (CI) individuals may empower the identification of mechanisms governing viral infection outcomes. Here, we provide the first in-depth analysis of adaptive immune receptor repertoires in individuals with current or past HCV infection. We demonstrate that SC individuals, in contrast to CI patients, develop clusters of antibodies with distinct properties. These antibodies' characteristics were used in a machine learning framework to accurately predict infection outcome. Using combinatorial antibody phage display library technology, we identified HCV-specific antibody sequences. By integrating these data with the repertoire analysis, we constructed two antibodies characterized by high neutralization breadth, which are associated with clearance. This study provides insight into the nature of effective immune response against HCV and demonstrates an innovative approach for constructing antibodies correlating with successful infection clearance. It may have clinical implications for prognosis of the future status of infection, and the design of effective immunotherapies and a vaccine for HCV.

WNK4 regulates airway Na+ transport: study of familial hyperkalaemia and hypertension.

BACKGROUND: WNK [With No K (lysine)] kinases are essential for regulation of blood pressure and potassium homeostasis. WNK4 expression was recently found not only in the distal nephron but also in chloride-transporting epithelia. To establish a physiological role for this distribution we studied patients with familial hyperkalaemia and hypertension (FHH), [pseudohypoaldosteronism type II (PHAII)], which is caused by mutations in WNK4. DESIGN: Measurement of nasal potential difference (NPD) and sweat electrolytes were performed in controls, in six subjects with FHH and ten subjects with cystic fibrosis (CF). RESULTS: Basal NPD was higher in FHH compared with controls (n = 20): 22.8 +/- 5.7 vs. 16.2 +/- 5.3 mV, respectively (P = 0.014). Maximal response to amiloride was also higher in FHH compared with controls: 14.8 +/- 3.5 vs. 10.0 +/- 4.8 mV, respectively (P = 0.03). In CF these values were 42.9 +/- 9.3 and 29.9 +/- 7.4 mV, respectively. The kinetics of the amiloride effect were faster in FHH, and as first reported here also in CF, compared with controls. At 30 s, amiloride-inhibitable residual PD in FHH was 50 +/- 30 vs. 81 +/- 9% in controls (P = 0.0003) and 56 +/- 7% in CF. The response to chloride-free and isoproterenol solutions, which determines chloride transport activity, was similar in FHH compared with controls [16.0 +/- 8.6 vs. 10.4 +/- 5.9 mV (P = 0.08)]. Sweat conductivity in FHH was 49.7 +/- 7.3 vs. 38.2 +/- 8.1 mmol (NaCl eq) L-1 in 16 controls (P = 0.007) and 94.0 +/- 19.3 in CF. CONCLUSIONS: Mutant WNK4 increases Na+ transport in airways, and therefore it is regulated by wild-type WNK4. This may be caused by a regulation of ENaC or a K+ channel.