| Popis: |
Transmission blocking monoclonal antibodies, 4B7 and 1245, targeting Pfs25, have been demonstrated to block the developmental stages of the malarial parasite inside the mosquitoes. In this work, anti-Plasmodium antibody fragments of 4B7 and 1245, designated as diabodies, were expressed in bacteria and refolded using a standardized method, with a yield of 0.1 and 0.4 mg per litre of culture, respectively. Dimeric species was detected for 4B7-Db, but not for 1245-Db, using glutaraldehyde cross-linking experiment. The quality of the purified refolded fraction was assessed with differential scanning fluorimetry (DSF). Refolded 4B7-Db, with a melting temperature of 59°C, recognized Pfs25 expressed on the surface of ookinete and zygote stages of Plasmodium in an immunofluorescence-based assay, whereas, 1245-Db, exhibiting a skewed melt profile, showed weak recognition. Further, refolded 4B7-Db recognized the linear epitope, on purified Pfs25 protein, both in the denatured and native state. Differential scanning fluorimetry can be potentially employed as a qualitative measure of functionality, to evaluate refolded proteins, with applicability for antibody engineering in passive immunization. |
