Dominating expression of negative regulatory factors downmodulates major histocompatibility complex Class-II expression on dendritic cells in chronic hepatitis C infection.
OBJECTIVE
To elucidate the molecular mechanisms leading to development of functionally impaired dendritic cells (DCs) in chronic hepatitis C (CHC) patients infected with genotype 3 virus.


METHODS
This prospective study was conducted on the cohorts of CHC individuals identified as responders or non-responders to antiviral therapy. Myeloid DCs were isolated from the peripheral blood of each subject using CD1c (BDCA1)(+) DC isolation Kit. Monocytes from healthy donor were cultured with DC growth factors such as IL-4 and GM-CSF either in the presence or absence of hepatitis C virus (HCV) viral proteins followed by LPS stimulation. Phenotyping was done by flowcytometry and gene expression profiling was evaluated by real-time PCR.


RESULTS
Non-responders [sustained virological response (SVR)-ve] to conventional antiviral therapy had significantly higher expression of genes associated with interferon responsive element such as IDO1 and PD-L1 (6-fold) and negative regulators of JAK-STAT pathway such as SOCS (6-fold) as compared to responders (SVR+ve) to antiviral therapy. The down-regulated genes in non-responders included factors involved in antigen processing and presentation mainly belonging to major histocompatibility complex (MHC) Class-II family as HLA-DP, HLA-DQ (2-fold) and superoxide dismutase (2-fold). Cells grown in the presence of HCV viral proteins had genes down-regulated for factors involved in innate response, interferon signaling, DC maturation and co-stimulatory signaling to T-cells, while the genes for cytokine signaling and Toll-like receptors (4-fold) were up-regulated as compared to cells grown in absence of viral proteins.


CONCLUSIONS
Underexpressed MHC class-II genes and upregulated negative regulators in non-responders indicate diminished capacity to present antigen and may constitute mechanism of functionally defective state of DCs.
Shallu Tomer, Sunil K Arora, Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
Shallu
S
Tomer
Shallu Tomer, Sunil K Arora, Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
Yogesh K
YK
Chawla
Shallu Tomer, Sunil K Arora, Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
Ajay
A
Duseja
Shallu Tomer, Sunil K Arora, Department of Immunopathology, Postgraduate Institute of Medical Education and Research, Chandigarh 160012, India.
Sunil K
SK
Arora
D000328:Adult; D000998:Antiviral Agents / Q000627:therapeutic use; D002478:Cells, Cultured; D003713:Dendritic Cells / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D015536:Down-Regulation; D005260:Female; D005434:Flow Cytometry; D020869:Gene Expression Profiling / Q000379:methods; D053263:Gene Regulatory Networks; D005802:Genes, MHC Class II; D005838:Genotype; D016174:Hepacivirus / Q000187:drug effects* / Q000235:genetics / Q000276:immunology*; D019698:Hepatitis C, Chronic / Q000188:drug therapy / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D054884:Host-Pathogen Interactions; D006801:Humans; D016130:Immunophenotyping / Q000379:methods; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D000998:Antiviral Agents; D014157:Transcription Factors
Dendritic cells; Hepatitis C; Major histocompatibility complex Class-II genes; Negative regulators; Non-responders