Estudo de marcação do anticorpo monoclonal anti-PBP2a com 99mTc [thesis]

Janio da Silva Mororó
Staphylococcus aureus is a major cause of life-threatening infections such as bacteremia and endocarditis. Unfortunately, many strains of this bacterial species have become resistant to certain antibiotics, including methicillin and amoxicillin. These strains are known as methicillin-resistant S. aureus (MRSA). The penicillin binding protein 2a (PBP2a) is the enzyme responsible for conferring resistance β-lactams antibiotics for MRSA, being one promising molecule for therapy with mAb. However,
more » ... esides the therapy, the methods of diagnosis are also inefficient because the diagnosis currently takes several days to produce a reliable result. Taking into account, the objective of this research was radiolabeling one anti-PBP2a mAb developed by Bio-Manguinhos/FioCruz-RJ, utilizing 99m Tc, for in situ diagnostic of the infectious caused by MRSA. First, anti-PBP2a mAb was reduced utilizing 2-mecaptoethanol (2-ME) for generate sulphydryl groups (-SH) and after to be labeled with 99m Tc. In this work, were utilized two techniques of direct method: Method 1, using tartrate and gentisic acid reagents, acting like transchelant and stabilizer agents, respectively; and Method 2, using one commercial kit of MDP. Besides the radiolabeling, the mAb reduced and mAb labeled with 99m Tc were submitted to immunoreactivity analysis, with SDS-PAGE non-reducing, Immunoblotting, ELISA and neutralization assay in vitro methods. The quantity produced of sulphydryl groups by mAb was satisfactory, approximately 5 per mAb, utilizing 6.500:1 of 2-ME:mAb molar ratio. The better labeling method was Method 2, with labeling yield of 73.5%, and showed a good stability after 2 hours (73.2%). The better formulation was: 0.5 mg of mAb anti-PBP2a, 10 µL of MDP kit, after resuspended with 5 mL of saline, and 75.48 MBq (2.04 mCi) of 99m Tc, reacting by 15 minutes. The labeled mAb maintained the immunoreactivity, utilizing immunologic and in vitro experiments. AcM-reduzido RESULTADOS E DISCUSSÕES
doi:10.11606/d.85.2012.tde-06032013-151412 fatcat:g2nrykxjvncozlvndfxp55vnjq