سال:1385 | دوره: | شماره: |تعداد مقالات:8

Background: IFN-g is mostly secreted by activated CD4+, CD8+ T cells and NK cells. This cytokine has immunomodulatory, anti-cancer and anti-microbial effects and is important for prophylaxis, diagnosis and treatment of chronic infections and cancers. Objective: The purpose of this study was to clone the full cDNA of human IFN-g and express it on CHO cell line. Methods: Lymphocytes from a healthy individual were isolated and activated by phytohaemagglutinin (PHA) in vitro. After 4 hours, total RNA extracted and first cDNA strand was synthesized. cDNA was amplified with primers containing EcoRI and NotI sites. The amplified fragment and the PcDNA3.1 vector were cut by EcoRI and NotI and ligated. The construct (pcDNA3.1-IFN-g) was transferred into E.coli (strain: DH5a) using CaCl2 method and selected by plating on a medium containing ampicillin. The construct sequence was confirmed by PCR and sequence analysis. Construct expression was achieved by performing a calcium phosphate-mediated transfection into CHO cells and followed by selection of stable drug (G418) resistant clones by limiting dilution assay (LDA). The IFN-g production by transected CHO cells was measured using ELISA technique. Results and Conclusion: Out of 33 grown transformed bacterial colonies, only 6 had the entire sequences of the insert and one of them was used for the transfection experiment. Out of 768 wells, 5 clones produced more than 100 ng/ml/106cells of IFN-g. Among the 5 clones, one with the maximum production of INF-g (143 ng/ml/106 cells) was selected and used for propagation.

Background: Neonatal sepsis is a life-threatening disease with an incidence of 1 to 10 per 1000 live births and a mortality rate of 5% to 25%. The clinical signs are non-specific and indistinguishable from those caused by a variety of neonatal noninfectious disorders. Objective: The aim of this study was to determine the importance of CD64 (FcgRI), a neutrophil surface marker, in early diagnosis of neonatal sepsis. Methods: The studied population comprised of 65 neonates with gestational ages of 27 to 38 weeks, suspected of having sepsis in the first 28 days of life and 12 healthy term neonates with physiologic hyperbilirubinemia. One ml of whole blood was obtained to determine CD64 expression on peripheral blood neutrophils by flow cytometry. Results: CD64 expression was significantly higher in the group with sepsis than the control (P < 0.001). Sensitivity and specificity of CD64 were 92.3% and 100%, respectively. The negative and positive predictive values of CD64 for identifying sepsis were 100% and 88%, respectively. Conclusion: Change in cell surface expression of CD64 on peripheral blood neutrophils may be considered as a sensitive marker for detection of neonatal sepsis if used in combination with other laboratory parameters.

Background: Helicobacter pylori infection is one of the most common gastrointestinal infections worldwide. Predominant T-helper 1 (Th1) responses with increased gamma interferon (IFN- g) levels have been proposed to play an important role in H. pylori-induced peptic ulcer. However, bacterial factors contributing to the initiation of Th1 polarization of H. pylori-specific immune responses have not been characterized. Objective: Comparing serum concentrations of IL-18 in H. pylori-infected peptic ulcer (PU) patients, H. pylori-infected asymptomatic (AS) carriers and healthy control group and its association with bacterial virulence factor CagA. Methods: Thirty H. pylori-infected PU patients (20 patients were positive for anti-CagA antibody and 10 patients were negative for anti-CagA antibody), 30 H. pylori-infected (AS) carriers (15 subjects with positive test for anti-CagA antibody and 15 subjects with negative test for anti-CagA antibody) and 20 healthy uninfected subjects were included in this study. Serum concentration of IL-18 was measured by ELISA method. Results: The mean serum levels of IL-18 in PU patients (333.2 pg/ml ± 158), was significantly higher (p<0.001) than those found in AS (146.5 pg/ml ± 90.1) and healthy control (82.2 pg/ml ± 45.7). In both PU and AS groups, mean serum IL- 18 levels in subjects with positive test for anti-CagA antibody were significantly higher than those observed in subjects with negative test for anti-CagA antibody. No significant difference was observed between serum IL-18 levels of healthy uninfected control and AS carriers with negative test for anti-CagA antibody. Conclusion: The results of the present study showed higher serum concentrations of IL-18 in peptic ulcer patients comparing with H.Pylori carriers and healthy controls. This difference in cytokine levels may be explained by differential expression of H.Pylori CagA gene during the course of the infection.

Background: Genotype DD and D allele of Angiotensin I Converting Enzyme (ACE) may be involved with an increased susceptibility to type 2 diabetes and diabetic nephropathy (DN). Objective: To investigate the relationship between ACE I/D polymorphism and type 2 diabetes in 261 Iranian case-control pairs. Methods: 170 patients (85 type 2 diabetics with nephropathy and 85 type 2 diabetics without nephropathy) and 91 healthy control subjects formed the studied groups. I/D polymorphism of the ACE gene were detected by polymerase chain reaction (PCR) utilizing specific primers. Results: The frequency of DD genotype in the DN group was higher than that of the type 2 diabetic patients (30.6% vs. 20%, P-value=0.157) and the control group (30.6% vs. 14.3%, P-value=0.006).The frequency of D allele in nephropathic patients was 58.2% as compared to type 2 diabetic patients without nephropathy 50.5% (P-value=0.19) and control subjects 37.3% (P-value=0.001). The frequency of D allele in type 2 diabetic groups was found to be higher than that in the control group (p<0.01). Conclusion: Data of this investigation concluded that the D allele of ACE gene is more frequent in type 2 diabetes (DM) but frequency of DD genotype and D allele in type 2 diabetic patients with nephropathy and the control subjects were insignificant.

Background: Thalassemia patients, comparing to normal population are more susceptible to hepatitis, because of frequent blood transfusions. Objective: To determine the immune response of children with major ک-thalassemia, by measuring antihepatitis B surface antibody (anti-HBs Ab) following the last HBV vaccine injection. Method: This study carried out on 215 thalassemic children who received three standard intramuscular recombinant HBV vaccines. Children age range was between 1- 4.5 with a mean age of 3.37 years. Based on the time lapsed since last vaccine injection, the subjects were divided into three groups; 0-15 months, 15-30 months and 30- 45 months, respectively. Based on the serum levels of anti-HBs antibody, subjects were categorized as: good responders (anti-HBs >100 IU/Lit), low responders (anti- HBs 10-100 IU/Lit) and non responders (anti-HBs <10 IU/Lit). Results: The mean range of anti-HBs level in the above mentioned groups were 205.34, 128.8 and 54.25 IU/lit, respectively (P<0.0001). In girls, the mean antibody level was 104.2 and in boys it was 95.8 IU/Lit (P>0.05). Out of 215 selected individuals 75 (35%) were good responders, 65(30%) low responders and 75 (35%) non-responders. Conclusion: Standard HBV vaccination in thalassemic children results in an immune response in more than 65% of the subjects. Therefore, assessment of anti-HBs antibody level, 45 months after the last vaccination is recommended.

Background: Decay of vaccine–induced antibody titres without boosting of the wild measles virus has been well documented. Revaccination against measles has reduced the prevalence of the disease worldwide. Revaccination may cause IgE induced anaphylaxis. Objective: To study measles IgG antibody in revaccinated populations and its relation to IgE induced hypersensitivity. Methods: Blood samples were taken from 800 volunteer army students aging between 18-22 years old after one month of nationwide revaccination in Tehran in the year 2004. Sera was collected and kept frozen until used. Anti-measles IgG antibody and total IgE antibody were measured by ELISA assay. Results: Data indicated that only 2.37% of subjects were negative for measles antibody (titre less than 500) after a single dose of booster vaccination. From those individuals with positive IgG, 200 cases (25%) had antibody titres over 5000 IU/Ml. The results showed a maximum IgE antibody titre of 1000 IU/Ml (p<0.02) in which thirty cases (3.75%) had IgE titres over 1000 IU/Ml (p<0.02). Conclusion: Single vaccination against measles during childhood is not sufficient for protecting against measles virus and revaccination is needed to recall specific immunity, although like other viral infections it may trigger IgE antibody responses in a small percentage of population.

Background: Varicella–zoster virus (VZV) causes varicella (chicken-pox) and herpes zoster, usually a mild disease which is diagnosed clinically with few complications. However, in neonates and healthy adults it can have a severe presentation. Herpes zoster results from VZV reactivation later in life. Objective: To estimate the seroprevalence of VZV in elementary school children aging 6-10 years old in Shiraz, Iran. Methods: A cross-sectional seroprevalence survey was conducted on 270 healthy subjects. All serum samples were investigated for immunoglobulin G (IgG) antibody against VZV using a commercial enzyme linked immunosorbent assay (ELISA). Results: Among the studied population, 175 (64.8%) had no detectable antibody levels. The overall seroprevalence rate was 35.2%. A breakdown of seropositivity to VZV according to age was as follows; 10 years-old, 50%,9 years-old, 48.2%, 8 years-old, 27.3%, 7 years-old, 32.1%, and 6 years-old, 13.2%. Conclusion: As VZV susceptibility in the studied age groups was higher than the expected rate, therefore childhood VZV vaccination is recommended in our region.

Background: Toxoplasmosis is a zeonotic disease with high seroprevalence worldwide. Several immunological methods have been described for diagnosis of toxoplasmosis. Objective: To determine the parasitemia priod in patients infected with toxoplasma using PCR and comparing serological data with molecular results. Methods: In this study 154 serum samples from patients with toxoplasmosis were examined. Presence of parasite DNA was evaluated using PCR method. IgG and IgM antibody titers were measured using IFA test. Results: Of 154 studied samples, 28 were positive for IgM and 60 were positive for IgG with titers higher than 1/400. PCR was performed on those samples having either IgG or IgM titers. Samples with IgM titers lower than 1/800 and higher than 1/3200 had no detectable level of parazite DNA. Parsetemia was detected in cases with IgG titer of 1/100 to 1/200. All samples with no detectable IgM and with IgG titers higher than 1/400 were negative when tested by PCR. Conclusion: IgM specific antibody titer between 1/800 and1/3200 represents a window opportunity in treatment of patients with toxoplasmosis. Absence of parasite"s DNA in patient with higher IgM antibody titer is explained by the effector mechanism of antibody for clearance of the parasite.