IMMUNOHISTOCHEMICAL DETECTION OF CD1A ANTIGEN IN FORMALIN-FIXED AND PARAFFIN-EMBEDDED TISSUE-SECTIONS WITH MONOCLONAL ANTIBODY-010

The immunoreactivity of a CD1a monoclonal antibody (MAb), denoted 010, was investigated by means of the streptavidin-biotin-peroxidase metho d in formalin-fixed and paraffin-embedded tissues from 47 cases. The s amples comprised reactive lymphoid proliferations of skin, tonsil, and lymph node including dermatopathic lymphadenopathy and Langerhans' ce ll histiocytosis, Hodgkin's and non-Hodgkin's lymphomas, and thymomas. Interdigitating and dermal dendritic cells, veiled cells, Langerhans' cells, and also cortical thymocytes and their neoplastic counterparts displayed immunostaining with MAb 010 in paraffin sections. These res ults are identical to previous ones reported for other CD1a MAbs in fr esh or frozen specimens. The findings suggest that the binding site of 010 is a fixation-resistant epitope of CD1a antigen which has not bee n previously identified.