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العنوان
Evaluation of Antigen-Specific Responses against genotype 1b and 4a Antigens among Egyptian Patients Infected with Hepatitis C Virus /
المؤلف
Galal, Iman Fathy.
هيئة الاعداد
باحث / ايمان فتحي جلال
مشرف / أحمد رفعت عزت
مشرف / أحمد عثمان مصطفى عجيزة
مشرف / سيد فكري عبد الوهاب
تاريخ النشر
2014.
عدد الصفحات
150 p. :
اللغة
الإنجليزية
الدرجة
الدكتوراه
التخصص
الكيمياء الحيوية ، علم الوراثة والبيولوجيا الجزيئية
تاريخ الإجازة
1/1/2014
مكان الإجازة
جامعة عين شمس - كلية العلوم - قسم الكيمياء الحيوية
الفهرس
Only 14 pages are availabe for public view

from 150

from 150

Abstract

SUMMARY
Hepatitis C virus is a widespread infectious disease in humans
with the negative implication of becoming chronic in most persons.
Patients infected with HCV are at risk of liver cirrhosis or
hepatocellular carcinoma at later stages. In Egypt, there is a high
prevalence averaging from 12 to 18% of the entire population. Despite
difficulties associated with extreme variability and mutability of HCV,
several vaccines that prevent initial infection or viral persistence, or that
clear viraemia in individuals with chronic HCV infections, are currently
in development. Trials are underway in search of vaccine that may
prevent chronic persistent infections in humans. Unfortunately none of
these trials are directed towards GT- 4 that is the predominant genotype
in Egypt. This study was designed to investigate the possibility that
Egyptians patients could get benefit from vaccine candidates directed
towards the HCV GT- 1b.
This cross sectional study was carried out to compare their HCVspecific
CMI responses to HCV GT- 4a and 1b peptide pools. Forty-five
subjects, who agreed to participate from the original HCV incidence
study among 859 HCW at risk of exposure to-, and infection with- HCV
at the Menoufiya University’s NLI, formed the study population. All
study subjects (21 chronic, 14 resolved and 10 controls) were tested for
HCV viral RNA and Abs then HCV RNA positive subjects were
confirmed to have GT- 4 HCV infections.
Summary
121
HCV-specific CMI in study groups was quantified using the
interferon gamma (IFN-γ) enzyme-linked immunospot (Elispot) assay
in response to two sets of 7 HCV genotype 4a and1b overlapping 15mer
peptide pools covering most of the viral genome. The phenotype of the
responding T cells to the HCV antigens and Treg cells was also
characterized by flow cytometry. In addition Interleukin 17 (IL-17)
gene expression upon stimulation by 4a and1b pool peptides was
quantified by real time PCR.
The results revealed a significant difference in ALT activities
among the studied groups while there was no significant difference
among the aforementioned groups in the demographic and clinical data.
A positive HCV-specific IFN- γ was elicited for 1-14 HCV pools in 17
(37%) of subjects tested. The total mean (±SEM) was 199±55
SFC/Million PBMCs for genotype 1b and 216 ±55.8 SFC/Million
PBMCs for 4a, respectively. There was no statistical difference in total
response between the two genotype antigen pools (p=0.833). Twenty
eight subjects out of 45 (62.2%) didn’t respond to any of the 14 tested
pools (non- responders). Differences between responders and nonresponders
for both genotypes 4a and 1b were statistically significant
(p=0.003; p=0.001, respectively). The average positive response to any
of the tested pools for each antigen set was 1.65±0.27 pools and
1.65±0.24 pools, respectively (p=0.5). A strong correlation was found in
the CMI responses to both GT-1b and GT-4a antigens among Egyptians
exposed to HCV infection. These antigens were immunogenic, flow
cytometric analysis of the phenotype of cells producing IFN-γ and IL-2
indicated that both CD4+ and CD8+ T-cell subsets are able to produce
Summary
120
these cytokines with higher frequency in the CD4+ T cell subset at least
by being double the percentage of CD8+ T cells in the blood.
A higher frequency of Treg was detected in the chronic group
rather than in the resolved and control groups but with no significant
difference. Upon stimulation of PBMCs with mixture of GT- 4a pooled
Ag peptides, enhanced IL-17 expression (up-regulation) was recorded
only in chronic subjects while it was down-regulated in resolved and
control. IL-17 was up-regulated after stimulation with mixture of GT-
1b pooled Ag peptides in resolved and control groups whereas it was
down-regulated in chronic subjects.
In conclusion, cross-strain recognition was indicated to be possible
and this will open the path for future considerations of HCV as
prophylactic and/or therapeutic vaccine candidate against HCV. The
present results revealed specific T cell immune responses, including
CD4+ and CD8+ T cell responses in HCV chronic and resolved
subjects in response to stimulation with 4a and 1b pool peptides