Monoclonal antibodies displaying a novel species specificity for the primate transformation-related protein, p53

Area of Science:

• Molecular Virology
• Immunology
• Cell Biology

Background:

• Simian virus 40 (SV40) large T antigen is known to associate with the cellular phosphoprotein p53 in virus-transformed cells.
• Understanding the p53-SV40 complex is crucial for investigating viral oncogenesis and cellular transformation.
• Existing antibodies to p53 have limitations in specificity and do not fully characterize the SV40-associated form.

Purpose of the Study:

• To generate novel monoclonal antibodies against human p53.
• To characterize the specificity of these new antibodies, particularly their interaction with the SV40 large T antigen-associated p53.
• To enable further investigation into the nature and function of the large T/p53 complex in human cells.

Main Methods:

• Generation of three new monoclonal antibodies (PAb1101, PAb1102, PAb1103) using SV40-transformed human fibroblasts.
• Immunological characterization of antibody binding to human and rodent p53.
• Assessment of antibody preference for the large T antigen-associated form of p53.

Main Results:

• The new antibodies define at least two non-overlapping epitopes on human p53, distinct from those recognized by previous antibodies.
• PAb1102 and PAb1103 show no reactivity with rodent p53, while PAb1101 exhibits significantly reduced reactivity with rodent p53 compared to primate p53.
• All three antibodies preferentially bind to the large T antigen-associated form of p53, with PAb1102 showing the most pronounced effect.

Conclusions:

• The novel monoclonal antibodies provide enhanced specificity for human p53, particularly the form complexed with SV40 large T antigen.
• These antibodies facilitate detailed studies of the p53-SV40 interaction and its role in cellular transformation.
• The distinct specificities of these antibodies open new avenues for exploring the functional implications of the large T/p53 complex.