Immune response to dna vaccine expressing transferrin binding protein a gene of Pasteurella multocida

Haemorrhagic Septicaemia (HS), an acute and fatal disease of cattle and buffalo is primarily caused by serotype B:2 or E:2 of Pasteurella multocida. The transferrin binding protein A (TbpA) has been found to act as immunogen and potent vaccine candidate in various Gram negative bacteria including P. multocida. The present study was carried out to evaluate the potential of this antigen as a DNA vaccine against HS in mice model. The tbpA gene of P. multocida serotype B:2 was cloned in a mammalian expression vector alone and along with murine IL2 gene as immunological adjuvant to produce monocistronic and bicistronic DNA vaccine constructs, respectively. The immune response to DNA vaccines was evaluated based on serum antibody titres and lymphocyte proliferation assay. A significant increase in humoral and cell mediated immune responses was observed in mice vaccinated with DNA vaccines as compared to non immunized group. Additionally, the bicistronic DNA vaccine provided superior immune response and protection level following challenge as compared to monocistronic construct. The study revealed that DNA vaccine presents a promising approach for the prevention of HS.

Transferrin Binding Protein of Staphylococcus aureus is not Essential for Iron-uptake from Transferrin in vitro / 감염과화학요법

BACKGROUND: Staphylococcus aureus produces siderophore and expresses transferring-binding protein for uptake of iron essentially required for multiplication under the iron-restricted conditions. We investigated which of the two iron-uptake systems is dominant or essential for S. aureus growth. METHODS: Streptonigrin-resistant mutant (SR-1) of S. aureus, isolated by repeated exposure to streptonigrin, was used in this study. SR-1 strain produced less amount of siderophore than the parent strain and did not express the transferring-binding protein. Growth and iron consumption of the two bacteria were compared during cultivation in the media containing various concentrations of iron, by measuring optical densities of the culture fluids at 600 nm and residual iron concentrations of the culture supernatants. RESULTS: Growth of the two bacteria in the iron-sufficient media containing various sources of iron was more active than in the iron-deficient media, in which iron concentration was 0.2 microgram/dL. Growth of SR-1 strain was markedly inhibited in the iron-deficient media with/without apotransferrin (0.5 mg/mL). However, growth of SR-1 strain did not show any difference in the iron-sufficient media containing FeCl3 (0.2 micrometer) and hemoglobin (0.5 mg/mL) as compared with that of the parental strain. Moreover, growth of the two bacteria did not show any difference in the media containing holotransferrin (0.5 mg/mL). There was no difference in iron consumption between the parental and mutant strains, evidenced by the residual iron concentration of the culture supernatants. CONCLUSION: Siderophore production is thought to be dominant or essential iron-uptake system for in vitro growth of S. aureus. The pathogenetic role of multifunctional transferring-binding protein, including transferring-binding activity and glycolytic enzyme activity, is expected to be established through further continued studies.

Transferrin Binding Protein of Staphylococcus aureus is not Essential for Iron-uptake from Transferrin in vitro / 감염과화학요법

BACKGROUND: Staphylococcus aureus produces siderophore and expresses transferring-binding protein for uptake of iron essentially required for multiplication under the iron-restricted conditions. We investigated which of the two iron-uptake systems is dominant or essential for S. aureus growth. METHODS: Streptonigrin-resistant mutant (SR-1) of S. aureus, isolated by repeated exposure to streptonigrin, was used in this study. SR-1 strain produced less amount of siderophore than the parent strain and did not express the transferring-binding protein. Growth and iron consumption of the two bacteria were compared during cultivation in the media containing various concentrations of iron, by measuring optical densities of the culture fluids at 600 nm and residual iron concentrations of the culture supernatants. RESULTS: Growth of the two bacteria in the iron-sufficient media containing various sources of iron was more active than in the iron-deficient media, in which iron concentration was 0.2 microgram/dL. Growth of SR-1 strain was markedly inhibited in the iron-deficient media with/without apotransferrin (0.5 mg/mL). However, growth of SR-1 strain did not show any difference in the iron-sufficient media containing FeCl3 (0.2 micrometer) and hemoglobin (0.5 mg/mL) as compared with that of the parental strain. Moreover, growth of the two bacteria did not show any difference in the media containing holotransferrin (0.5 mg/mL). There was no difference in iron consumption between the parental and mutant strains, evidenced by the residual iron concentration of the culture supernatants. CONCLUSION: Siderophore production is thought to be dominant or essential iron-uptake system for in vitro growth of S. aureus. The pathogenetic role of multifunctional transferring-binding protein, including transferring-binding activity and glycolytic enzyme activity, is expected to be established through further continued studies.

Immunohistochemical Study on the TfBP Expression in the Embryonic Chick Cerebellum / 대한해부학회지

We have previously demonstrated that transferrin binding protein (TfBP) is a reliable marker for mature oligoden-drocytes (OLGs) in the avian central nervous system (CNS). Unlike mammalian CNS in which OLGs are generated largely postnatally, avian OLGs are differentiated during embryonic development of CNS. In this study, several aspects of TfBP(+/-) OLG development were immunohistochemically examined in the embryonic chick cerebellum : (1) change in shapes of immature cells with respect to time and to location within the cerebellum, (2) possible sites of origin, and (3) pathways of precursor cell migration. Our results indicate that TfBP expression gradually increases and extends from the deep portion of the white matter to gray matter with proportion to progress of cerebellar development. A few TfBP? cells were first observed in the deep portion of the cerebellum at E9. At E13, TfBP(+/-) cells were distributed evenly within the white matter. At E17, many TfBP(+/-) OLGs were located at granular layer and at the near place of Purkinje cell layer. At E20, a large number of TfBP cells appeared at the granular layer with a few in the molecular layer. Our data demonstrated distinct patterns of morphology and location of TfBP(+/-) OLGs in the cerebellum during development and suggest a role of TfBP in OLG development.

Iron-uptake System of Staphylococcus aureus According to the Antibiotic Susceptibility / 감염

OBJECTIVE: It was reported that a few antimicrobial agents influenced on the activity of bacterial iron- uptake system (IUS). In the present study, we tried to investigate the relatedness between the resistance of antibiotics and the activity of the two high-affinity IUS, siderophore-mediated IUS and transferrin-binding protein (SA-tbp)-mediated IUS, of Staphylococcus aureus clinical isolates. METHODS: Total 71 strains including the standard ATCC 6538 strain were used. Seventy strains were isolated from the second or third line general hospitals from 1998 to 1999. Antimicrobial susceptibility test was performed by disk diffusion method. CAS agar diffusion assay was used for the measurement of staphylococcal siderophore. To visualize the expression of SA-tbp, Western blotting using human transferrin conjugated with horseradish peroxidase was performed. RESULTS: Among the nine antimicrobial agents, only the susceptible strains to oxacillin produced more siderophore compared to the resistant strains (P0.05). There were no antibiotics related to the expression of SA-tbp (P>0.05). CONCLUSION: These results indicate that only oxacillin (OXAC) influences on the production of staphylococcal siderophore and the further consecutive study about the action mechanism of OXAC is necessary.

Effect of Iron - Uptake Mechanisms of Staphylococcus Aureus on the Growth in Human Body Fluids / 감염

BACKGROUND: We could establish a streptonigrin-resistant strain called SR-1 strain from Staphylococcus aureus ATCC 6538 as a parental strain and characterize SR-1 strain as defective in the iron-uptake mechanisms including production of siderophores and expression of transferrin-binding protein on the cell wall. We performed this study to elucidate effect of the iron-uptake mechanisms on the growth in human body fluids. METHODS: Growth kinetics of SR-1 strain were compared with those of the parental strain and the increase of unsaturated iron-binding capacity (UIBC) was measured. Siderophore production and expression of transferrin-binding protein were detected by CAS diffusion assay and ligand-blot method probed with human transferrin conjugated horseradish peroxidase, respectively, as the strains were cultivated in normal pooled sera, ascitic fluid and pleural effusion. RESULTS: Siderophores activity in the body fluids could not be detected by the CAS diffusion assay. The parental strain expressed the transferrin-binding protein on the cell wall during the growth in ascites and pleural effusion except the sera whereas SR-1 strain did not. Growth kinetics showed that SR-1 strain grew sluggish compared to the parental strain. The peak of increase of UIBC of the parental strain was observed at the mid-exponential growth phase and the increase of UIBC of SR-1 strain was either lower than that of the parental strain or not changed. CONCLUSION: The iron-uptake mechanisms of S. aureus, especially expression of transferrin-binding protein, play a significant role in growing in the body fluids.