Polymorphism and antigenic specificity of monocytic acid esterase (EC 3.1.1.6)

With the aim to provide a biochemical or immunological marker for human blood monocytes, their differentiational derivatives, and neoplastic variants the polymorphism of acid α-naphthyl acetate esterase was investigated. Using an isoelectric focusing technique it could be shown that the five enzyme variants of normal human blood monocytes, which do not occur in other human blood cell types, were regularly detectable in human peritoneal and alveolar macrophages. Antisera, raised against isoenzymes of monocytic acid esterase in rabbits, reacted in all cases with every five isoenzymes of blood monocytes; no cross-reactivity was observed with the isoenzymes of acid esterase obtained from purified human granulocytes, peripheral lymphocytes, B lymphocytes, and thymocytes as shown by immunoprecipitation. The results indicate that monocytic acid esterase and its variants could be regarded as a biochemical as well as immunological marker for this cell line.