[Antibodies to synthetic peptides for the detection of survivin in tumor tissues]

[Antibodies for detection of E/K amino acid substitution in 129 position of the survivin sequence]

Survivin is an oncofetal protein involved both in inhibiting of apoptosis and in cell cycle regulation. The functions of survivin are defined by its structural state. Due to nature polymorphism, survivin cancontain either E or K amino acid in 129 residue, and K129 is commonly acetylated. Only the protein having acetylated K129 tends to form dimeric structure. Thus, antibodies detecting the amino acid substitution can be a useful tool for structural and functional research of the protein. To obtain the antibodies specific to amino acid substitution E129/K129 peptide fragments overlapping 129 amino acid residue were synthesized, rabbits were immunized with the peptides and affinity purification of the antibodies on sepharose conjugated with the peptides was carried out. The data of ELISA and western blot showed that antibodies obtained were able to detect amino acid substitution E129/K129 in the recombinant and endogenous survivin.

[Obtaining of the affinity purified antibodies against survivin for the structure functional study of the protein]

Tumor-associated protein survivin is the bifunctional protein which can participate either in cell division regulation or in apoptosis inhibition depending on its localization and structure state. The aim of this work was to obtain monospecific antibodies useful for investigation of protein structure and functional features. Six affinity purified antibodies directed to different protein regions were obtained. The ability of antibodies obtained to detect survivin in tumor cells and breast cancer tissues was studied. It was shown that antibodies to (1-22) and (95-105) survivin fragments have the highest specific activity. In western-blot antibodies to (1-22) region predominantly binds with survivin-containing complex, which may be the survivin dimer as we suppose, while antibodies to (95-105) region detects only monomeric form of the protein. Breast cancer tissues study demonstrated that survivin monomer presents only in the tumor core tissues, while survivin-containing complex is expressed both in tumor core and tumor periphery tissues. It was shown that antibodies to (1-22) fragment detect predominantly nuclear survivin, which participates in mitosis regulation, while antibodies to (95-105) fragment gave nucleoplasm and cytoplasm staining at all stages of cell cycle. Thereby antibodies obtained are the useful tool for structure-functional study of survivin.