Caracterização da atividade ligante e da função efetora de Anticorpos humanizados AntiCD3 Humano

AUTOR(ES)

Hernandez Moura Silva

DATA DE PUBLICAÇÃO

2008

RESUMO

Anti-CD3 antibodies have been used for the prevention of organ allograft rejection and are also considered a promising immunotherapic for autoimmune diseases treatment. Currently, there is only one anti-CD3 antibody approved by FDA for clinical use, the OKT3. Unfortunately, due to its murine origin, it promotes an immunogenic reaction when administrated, limiting its long-term use and reducing the treatment effectiveness. To solve this problem we have proposed humanized versions of this anti-CD3 to avoid its immunogenic properties. In this work was evaluated the binding activity and effector function of two humanized anti-CD3 antibodies. The first one has the murine residue threonine (T) 86 VH position while the second version shows the human residue arginine (R) at position 86 in VH. Modeling analysis indicated that this position is structurally important. To express the recombinant antibodies we constructed a dicistronic expression vector and produced the immunoglobulins in CHO cell lines. To analyze the binding activity and effector function, the recombinant proteins were previously purified by affinity chromatography. The results show that humanized antibodies were able to binding to the human CD3 on the T lymphocyte surface. However, they werent able to completely block OKT3 binding to T lymphocyte surface on competitive assays. Along with structural analysis, this data indicate an affinity loss of humanized versions probably due the substitution of important residues on humanized VL. The humanized versions also presented a less mitogenic activity than that observed by OKT3, corroborating the affinity loss of these antibodies. These data suggest that the humanized antibodies are able to bind to human CD3, but the humanization procedure caused a decrease on recombinant antibody affinity, compared with OKT3. To restore the binding activity of these antibodies specific mutations and back mutations must have to be taken in order to permit its future clinical use evaluation.

ASSUNTO(S)

ciencias biologicas cho humanização anti-cd3 anticorpos monoclonais

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