Iranian Biomedical Journal
Year:2002 | Volume:6 | Issue:1|Papers Count:8

Unresponsiveness to hepatitis B surface antigen (HBsAg) has been shown to be associated with dysfunction of the presenting cells (APC) and defect in the specific B-lymphocyte and/or T-lymphocyte repertoires. Direct determination of the frequency of specific T-lymphocytes together with complementary analysis of the naive circulating immune cells could provide valuable information about the cellular basis of unresponsiveness to HBsAg. In this study, the phenotypic characteristics of peripheral blood mononuclear cells (PBMC) from healthy adult high-responders (n = 19), intermediate-responders (n = 11), low-responders (n = 9) and non-responders (n = 6) to recombinant hepatitis B vaccine were investigated and compared. The proportions of circulating B-lymphocytes (CD19+ cells), T-lymphocytes (CD3+ cells) and monocytes (CD14+) were similar in all groups of responder individuals (14%, 55-60% and 11-13%, respectively) compared to non-responders (16%, 64% and 9%, respectively). These results suggest that the cellular basis for the lack of response to HBsAg is not associated to a generalized deficiency of immune cells in the non-responder subjects, rather it may reflect a defect in HBsAg-specific B or T cells.

By immunizing mice with killed whole bacterial cells of Brucella abortus S (99), a panel of six hybridomas producing monoclonal antibodies (mAb) specific for the surface antigens of this bacterium were produced. ELISA was used to screen the hybridoma supernatants. Immunoblots of the cell extract indicated that three mAb were specific for S-LPS (Ba-1, Ba-2, Ba-3) and three others were reactive with major outer membrane proteins (OMP) (Ba-4, Ba-5, Ba-6). The OMP recognized by these antibodies were the proteins with molecular masses of 25-27 kDa (Ba-4, Ba-5) and 36-38 kDa (Ba-6). None of the four mAb including Ba-3, Ba-4, Ba-5 and Ba-6 cross reacted with any other bacteria close to Brucella abortus, but Ba-1 and Ba-2 cross reacted with B. melitensis 16M and B. suis. By using cell extract and killed whole cell Ag in ELISA, it was indicated that all mAb except Ba-6 have better reactivity with cell extract Ag, but Ba-6 mAb reacted with killed whole cell Ag better than cell extract Ag

Avian influenza is an important disease of poultry with the potential to cause major epidemics resulting in significant economic losses. The presence of avian influenza viruses (AIV) in chickens in Iran has not been previously reported. An avian influenza outbreak in broiler, layer and breeder farms occurred during a very hot summer in July 1998. Three AIV isolates designated as 101, 102 and 103 were isolated from lung, tracheal cloacal samples of layer, breeder and broiler chickens, in embryonated chicken eggs. The presence of AIV in allantoic fluid cells was confirmed by indirect immunofluorescence assay using a monoclonal antibody against type A nucleoprotein. The viruses were further classified as H9N2 subtype in hemagglutination inhibition and neuraminidase inhibition tests using 15 hemagglutinin and 9 neuraminidase subtype specific antisera. The pathogenicity of AIV isolates was carried out in 4-6-wk-old chickens. No birds died within 10 days after inoculation of infectious allantoic fluids. Therefore, the representative Iranian layer, breeder and broiler AIV strains were classified as non-highly pathogenic avian influenza viruses pathotype. Isolation of the same subtype and pathotype of AIV from different flocks suggested that the H9N2 AIV subtype is a common pathogen involved in poultry industry respiratory disease outbreak

Human papillomavirus (HPV) DNA has been identified in esophageal carcinomas. However, the incidence of HPV varies significantly in different geographical locations. In this study, neoplasms from Turkmen Sahra, a region in Golestan province in northeast part of Iran, with a high incidence of squamous cell carcinoma were analyzed for the presence of HPV DNA. Turkmen Sahra is located in the cancer belt in Asia. Eighty-five squamous cell carcinomas were examined for the presence of HPV DNA. PCR was utilized to amplify a 124-bp segment of the HPV L1 gene using the consensus primers. The amplified region was subsequently sequenced to identify the HPV. The results indicated that the rates of HPV detection in squamous cell carcinoma specimen for men and women were 52.8% and 43.7% respectively. The positive cases included HPV-16 (54.7%), HPV-18 (4.8%), HPV-6 (14.3%), HPV-66 (7.1%), HPV-52 (4.8%) and 14.3% of cases were positive for more than one type of HPV. Human papillomavirus type 16 that can be potentially oncogenic was prevalent in 54.8% of the cases of esophageal squamous cell carcinoma. Our results confirm the previously reported HPV involvement in the esophageal squamous cell carcinoma, and support the possible role of HPV as an etiological agent in esophageal carcinogenesis

In this study, mutant forms of Bacillus thuringiensis spp. israelensis (H14) were produced. These mutants were identified when the cells were cultured on chloramphenicol plates and stained with crystal violet. Protoplasts of the mutants were isolated by enzymatic digestion (lysozyme) of the cell walls at the presence of an osmotic stabilizer. The protoplasts were induced to fuse to each other in the presence of PEG 6000. The frequency of regeneration and recombination was 80% and 2´10-4, respectively. In order to survey the effect of protoplast fusion on production of toxin, anti-serum against pure toxin was raised in rabbit and was used in single radial immunodiffusion. The comparison of d-endotoxin concentration between B. thuringiensis fusion and the wild type strains showed that B. thuringiensis fusion has 1.48 time more toxin than wild type

Cloning and expression of the L-phenylalanine dehydrogenase gene, from B. sphaericus in E. coli were done. The gene was cloned in the vector pET16b and transformed into E. coli BL21 (DE3). The functional form of the L-phenylalanine dehydrogenase enzyme was purified by affinity purification techniques, taking advantage of the ability of this enzyme to bind to the nucleotide site affinity dye, Reactive Blue 4. Approximately 3 mg of highly purified recombinant enzyme was obtained from 950 mg cell pellet (wet weight). The Relative molecular mass of the L-phenylalanine subunits was about 41 kDa by 10% SDS-PAGE. Using this method, the enzyme was obtained with a yield of 28%, and had a specific activity of 577.3 U/mg protein, which is purified 88 times. This method was provided a facile and effective way for preparing the enzyme with a good yield that suitable for analytical purposes

In order to find a prophylactic supplementation for individuals who are at risk of exposure to ionizing radiation, we attempted to evaluate the effect of Vitamin E (Vit-E), a biological free radical scavenger, on restoration of hepatic lipid peroxidation (LPO) and lipid profile (LP) changes induced by sublethal γ- radiation in BALB/c mice. The concentrations of cholesterol and phospholipid were determined in control and irradiated mice. Also, changes in lipid peroxidation and lipid profile were assessed by measuring the level of malonyldialdehyde, lipid hydroperoxides, and conjugated dienes. Our results showed that sublethal γ-radiation caused significant changes in hepatic lipid peroxidation and lipid profile. However, Vit-E supplementation was able to restore the changes of lipid peroxidation and lipid profile in irradiated mice. We have concluded that the mice that received Vit-E supplementation were able to tolerate biomembrane damage provoked by 1.09 Gy for 3 days γ-radiation. This supports the hypothesis that Vit-E may afford an efficient protection against ionizing radiation. However additional studies using higher doses of γ-irradiation should be performed

The enzymatic potential of the cultured plant cells can be employed for bioconversion purposes. Plant enzymes are able to catalyze regio- and stereo-specific reactions, and therefore can be applied for the production of desired substances. The biotransformation of foreign substrates with suspension cells of Peganum harmala was tested with (±) phenylethyl propionate. The callus cultures of Peganum harmala were established from cotyledons, and healthy suspensions grown using Murashige and Skoog medium. In order to investigate the specificities of the hydrolysis, (-) and (+) phenylethyl propionate isomers were added to the cultures. The phenylethyl propionate isomers were converted to their corresponding alcohols. The two isomers showed different rates of conversion during the first 24 hours after feeding. These cultures were able to hydrolyse specifically the propionate group in (±) phenylethyl propionate. It was found that the cultured cells of P. harmala have the ability to hydrolyse the racemic phenylethyl propionate stereoselectively.