The macrophage electrophoretic mobility test for malignancy.

Lymphocytes obtained from the blood of patients suffering from malignant disease liberate, when incubated with a basic protein obtained from carci­ nomatous tissue or the brain, a substance ( slowing factor ) which reduces the electrophoretic mobility of guinea pig macrophages. Lymphocytes from normal subjects or patients with non malignant tumors do not liberate this slowing factor. The macrophage electrophoretic mobil­ ity test (M EM test) for malignant disease was developed by Field and Caspary in 1970 as a result of some unexpected results obtained during the study of the reaction of lymphocytes to basic proteins extracted from human brain and sciatic nerve.9 These proteins, termed encephalitogenic factors or E F , which had been isolated and par­ tially characterized by these and other in­ vestigators,3 cause allergic encephalomye­ litis or neuritis when injected with Freund’s adjuvant into guinea pigs. Field and Cas­ pary wished to discover whether or not blood lymphocytes obtained from patients with carcinomatous neuropathy or degen­ erative diseases of the nervous system were sensitized to EF. Sensitization was de­ tected, as described in detail, by measuring the effect of the products of interaction of lymphocyte and E F on the electrophoretic mobility of guinea-pig peritoneal macro­ phages.8 As expected, blood lymphocytes obtained from normal subjects and patients with benign neoplasms were not sensitized; sensitized lymphocytes occurred in patients with carcinomatous neuropathy and degen­ erative diseases of the nervous system. The unexpected finding was the occurrence of sensitized lymphocytes in all subjects in the group of patients with malignant neo­ plasms not of the nervous system, irrespec­ tive of type or situation of the lesion. This finding, which has been confirmed by inde­ pendent investigators,14’15 provides the ba­ sis for the MEM test. P rin cip le o f th e M EM T est Sensitized lymphocytes, obtained from the blood of patients with malignant dis­ ease, when incubated with E F or certain other specific basic protein antigens pro­ duce a substance, probably a protein,2 which reduces the electrophoretic mobility of macrophages. It is believed that this substance, macrophage slowing factor or MSF, occurs on the plasma membrane of sensitized lymphocytes from which it is released by the antigen.6 M SF may be