Antibodies biotinylated using a synthetic Z-domain from protein A provide stringent in situ protein detection.
Antibody-based protein profiling on a global scale using immunohistochemistry constitutes an emerging strategy for mapping of the human proteome, which is crucial for an increased understanding of biological processes in the cell. Immunohistochemistry is often performed indirectly using secondary antibodies for detection, with the benefit of signal amplification. Direct immunohistochemistry instead brings the advantage of multiplexing; however, it requires labeling of the primary antibody. Many antibody-labeling kits do not specifically target IgG and may therefore cause labeling of stabilizing proteins present in the antibody solution. A new conjugation method has been developed that utilizes a modified Z-domain of protein A (ZBPA) to specifically target the Fc part of antibodies. The aim of the present study was to compare the ZBPA conjugation method and a commercially available labeling kit, Lightning-Link, for in situ protein detection. Fourteen antibodies were biotinylated with each method and stained using immunohistochemistry. For all antibodies tested, ZBPA biotinylation resulted in distinct immunoreactivity without off-target staining, regardless of the presence of stabilizing proteins in the buffer, whereas the majority of the Lightning-Link biotinylated antibodies displayed a characteristic pattern of nonspecific staining. We conclude that biotinylated ZBPA domain provides a stringent method for antibody biotinylation, advantageous for in situ protein detection in tissues.
Department of Immunology, Genetics and Pathology, Science for Life Laboratory, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden (SA,NA,FP,AA).
Sandra
S
Andersson
Anna
A
Konrad
Nikhil
N
Ashok
Fredrik
F
Pontén
Sophia
S
Hober
Anna
A
Asplund
D000906:Antibodies / Q000737:chemistry*; D019921:Biotinylation; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000032:analysis*; D013205:Staphylococcal Protein A / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000737:chemistry; D046888:Tissue Array Analysis / Q000379:methods
D000906:Antibodies; D011506:Proteins; D013205:Staphylococcal Protein A
antibody; biotin; conjugation; protein detection; tissue microarray