Toll-like receptor-9 triggering modulates expression of α-4 integrin on human B lymphocytes and their adhesion to extracellular matrix proteins

OBJECTIVE

The interaction of human B lymphocytes as recirculating cells with their microenvironment components including fibronectin is an instrumental process that directs their further responses in an inflammatory milieu or during their development in secondary lymphoid organs. Factors derived from extracellular environment, including those of pathogens, termed pathogen-associated molecular patterns, may have effects on this interaction, yet no study to date has addressed these effects. In this study, we explored the effect of Toll-like receptor 9 (TLR9) triggering on the interaction of normal B cells with fibronectin and collagen.

MATERIALS AND METHODS

The synthetic analog of TLR9 ligand, CpG-C, was used for stimulating the cells. The expression pattern of very late antigen-4 integrin was studied by fluorescence-activated cell sorting and Western blotting experiments, and cell adhesion was analyzed by fluorometric adhesion assay.

RESULTS

CpG at 0.5 μM upregulated fibronectin receptor (very late antigen-4) expression and cell adhesion, and increasing the CpG concentration did not have further effect. Blocking experiments with TLR9 signaling inhibitor, TTAGGG, anti-α4 antibody, and IκBα phosphorylation inhibitor, Bay 11-7082, confirmed that the CpG-induced induction level was TLR9 (partly), very late antigen-4, and nuclear factor-κB-mediated, respectively.

CONCLUSIONS

This study indicates that TLR9 triggering on B cells influences their interaction with extracellular matrix, which will be critical in modulating activation of these cells in conditions, such as infections, and gives a basic insight into the contribution of innate immunity elements in B-cell functional responses.

Evaluation of Fast-ELISA versus standard-ELISA to diagnose human fasciolosis

BACKGROUND

The present study was conducted to evaluate and compare a fast-ELISA (F-ELISA) method versus standard-ELISA (S-ELISA) to diagnose human fasciolosis.

METHODS

Serum samples were obtained from 35 individuals infected with fasciolosis, 27 infected with other parasitoses and 22 from healthy people. The samples were examined with S-ELISA (30-minute incubation periods) and F-ELISA (10-minute incubation periods) for total antibody response against fasciolosis.

RESULTS

The optimum conditions for S-ELISA and F-ELISA were respectively as follows: antigen 10 and 5 µg/mL, sera 1:500 dilution for both, peroxidase-conjugated goat anti-human IgG diluted 1:7000 and 1:10000. Data were analyzed using SPSS version 11.0. Cut-off vale for S-ELISA and F-ELISA was determined as 0.56 and 0.42, respectively. The sensitivity, specificity; positive, and negative predictive values were detected as 97.2%, 100%, 94.6%, and 95.6% for both tests.

CONCLUSION

Cut-off values, sensitivity, specificity, and other important parameters of the two evaluated tests determined that the F-ELISA method could be used with no detectable difference.

Gene cloning, expression and serological evaluation of the 12-kDa antigen-B subunit from Echinococcus granulosus

A 12-kDa subunit of antigen B from Echinococcus granulosus has recently been cloned, expressed and used in diagnostic ELISA to test human sera for evidence of cystic echinococcosis. The performance of the ELISA based on the recombinant antigen (rAgB) was compared with that of similar assays based on native antigen B (nAgB) or hydatid-cyst fluid. For the preparation of the rAgB, total RNA was extracted from Ec. granulosus protoscoleces so that antigen-B complementary DNA could be synthesised, amplified by PCR, and then cloned into the pQE30 expression vector. The recombinant plasmid was transformed in Escherichia coli and induced using isopropyl-beta-D-thiogalactopyrano-side. Bacterial samples were collected, lysed and then analysed by SDS-PAGE and western blotting. The recombinant protein was purified by affinity chromatography. Although the performance of the ELISA based on cyst fluid appeared identical to that of the assay based on the recombinant antigen (with a sensitivity, specificity, positive predictive value and negative predictive value of 96.0%, 97.0%, 97.2% and 95.5%, respectively), the corresponding results for the ELISA based on nAgB (98.6%, 100%, 100% and 98.5%) were slightly better. Despite this difference (which was not statistically significant), the comparative ease with which large quantities of the recombinant antigen could be produced make the antigen a potentially useful tool in the diagnosis of cystic echinococcosis.

Serological Evaluation of EgAgB16 kDa, a Recombinant Antigen from Echinococcus granulosus for Diagnosis of Human Hydatidosis

BACKGROUND

Regarding that accurate diagnosis of human hydatidosis still needs more investigations, the present study was conducted to clone, express, and evaluate the gene encoding AgB subunits (EgAgB16 kDa) from Echinococcus granulosus (Iranian G1 strain) and its evaluation by ELISA test.

METHODS

DNA was extracted from protoscoleces and was utilized by PCR for strain identification. Total RNA was prepared with RNeasy protect mini kit from E. granulosus (Iranian G1 strain) protoscoleces collected from naturally infected sheep with hydatid cyst. Recombinant AgB16 kDa was produced using pETDuet as vector and evaluated by ELISA method. A panel of sera including hydatid cyst-infected individuals (n=72), healthy individual (n=48), toxoplasmosis (n=4), strongyloidosis (n=4), kala-azar (n=5) and tuberculosis (n=5) were examined using this recombinant antigen.

RESULTS

Recombinant protein was purified by affinity chromatography using His-Tag column. After purification, recombinant protein was confirmed by western blot analysis using His Tag monoclonal antibody or hydatid positive human serum. The sensitivity, specificity; positive and negative predictive values were calculated as 93.5%, 95.6%, 96% and 92.9%, in that order. The cut-off point was detected 0.3 for rAgB16.

CONCLUSION

While the produced recombinant AgB16 kDa showed promising results in diagnosing human hydatidosis, but more investigations should be implemented to reach an accurate gold standard.