Immunohistochemistry of Large Granular Lymphocyte Leukemia, Rat

Abstract

The large granular lymphocyte of the rat, the effector cell of natural killer (NK) activity, possesses specific antigenic markers which allow one to use them to identify the normal and neoplastic LGL in frozen and fixed tissue sections. Many of them represent cell surface glycoproteins with unknown cellular functions. In normal LGLs, antigens immunoreact with monoclonal antibodies OX-1 (CD45), W3/13, ASGM1, OX-34 (CD2), and OX-8 (CD8) (Reynolds, p. 103, this volume; Barclay 1981; Brideau et al. 1980). The OX-8 antibody is available from Sera Labs., Oxford, UK, or Accurate Chemical & Scientific Corp., Westbury, New York. OX-8 reactivity is also found on rat cytotoxic/suppressor T cells and parotid salivary gland epithelium. In young nude rats, OX-8 is not found on cytotoxic/suppressor T cells (Ward et al. 1983) but may be found on these cells in older nude rats. OX-8 im-munoreactivity is well protected by freezing, Bouin’s, Zenker’s or B-5 fixatives but poorly preserved with formalin. After trypsinization, immunoreactivity may be seen in formalin-fixed tissues, but this phenomenon is not consistently found. Most other cell surface antigens of normal or neoplastic rat LGLs can be demonstrated only with frozen sections, while other antigens such as esterases and acid phosphatase can be demonstrated by the histochemistry of frozen sections as well. In normal tissues, reactivity is seen in the T-cell areas of the lymph nodes and spleen and in areas in which large granular lymphocytes are found, including the intestinal lamina propria and within the epithelial layer of the small intestine. Inflammatory lymphocytes are often reactive, especially in nude rats (Ward et al. 1983). Cell surface staining of OX-8 is evident in normal large granular lymphocytes and neoplastic large granular lymphocyte leukemia cells (Fig. 207).