Tissue typing antigens

Petersdorf EW, Anasetti C, Martin PJ, Hansen JA. Tissue typing in support of unrelated hematopoietic cell transplantation. Tissue Antigens. 2003 Jan 61(l) l-ll. 

The above discussion indicates that although 0.01 M sodium citrate buffer (pH 6.0) is commonly used, it is not a universally ideal antigen retrieval fluid for all types of tissues and antigens. If published information is not available with regard to the best antigen retrieval fluid for the antigen under study, the ideal retrieval fluid for each type of epitope must be determined by trial and error. 

Also, different forms of an antigen require different concentrations of the antibody for their maximal detection. This is exemplified by the PC-10 primary antibody, which identifies PCNA antigen at a dilution of 1 1000 in epithelial cells in normal colon tissue, whereas a dilution of 1 400 is required to localize these proliferating cells in adenomatous polyps (Holt et al., 1997). In contrast, some types of antigens (e.g., Ki-67) can be optimally detected in various tissue types at the MIB-1 dilution of 1 50, using the microwave heating antigen retrieval method. However, in a few studies MIB-1 dilutions of 1 20 to 1 100 have been used. 

Determine the optimal pH of antigen retrieval solution for each antigen. Citrate buffer (0.01 M) adjusted to pH 6.0 with HC1 is used widely. Determine the desired temperature based on the type of tissue and antigen under study. For fatty tissues, 90°C is recommended adjust the duration of heating accordingly. Place slides in plastic Coplin jars containing the... 

Proteolytic enzymes cleave specific amino acid sequences within the peptide chain of the digested protein since proteases differ in their cleavage specificities, they can have markedly different effects upon tissues depending upon the type of fixative used for processing the tissue, the antigenic target, and the epitope recognized by the antibody. 

Laboratory assessment includes indicators of general operative health (e.g., electrolytes, acid-base status, clotting profile, full blood cell count, and cross-matching). In addition, full human leukocyte antigen (HLA) tissue typing is undertaken, in addition to a full screen for infectious diseases, particularly cytomegalovirus (CMV), hepatitis, herpes, and HIV status, as these infections can be activated by immunosuppressive therapy. 

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