Preparation And Radioimmunoscintigraphy Of A Monoclonal Antibody Against Human Granulocytes

The localization and diagnosis of inflammatory areas of carcinomas and clinically concealed infectious diseases is beneficial not only to disclose the etiology of inflammatory areas, but also to determine effective therapeutic measurements, reduce complications and improve prognosis.Due to the chemotaxis to inflammation of granulocytes, In 1986 Locher initially reported that I25I-labelled monoclonal antibody against granulocytes was a protential agent for the localization of inflammational areas. It was well known that monoclonal antibodies against granulocytes such as BW250/183N AK47 were prepared during the preparation of monoclonal antibodies against cancer embryo antigen(CEA). They were familiar monoclonal antibodies for radioimmunoscintigraphy of inflammatory areas at overseas. Now "Tcm labelled monoclonal antibodies against human granulocytes were used for radioimmunoscintigraphy of clinilcal osteoarthritis and they are widely used both to diagnosis and detect osteomyelitis and examine deep-seated inflammatory areas. The kits of MoAb against granulocytes are widely used at abroad, but it was impossible for most Chinese patients to be used because of the higher price of kits.In contrast to the rapid development of monoclonal antibodies against granulocytes, it was infrequently studied in our country because the antigens of granulocytes were difficultly determined. Therefore, a novel MoAb against granulocytes was produced in our laboratory by the intraperitional routing procedure, which was named SZ-102. It was characterized as IgGl subclass by the double immunodiffusion analysis. It was confirmed by flow cytometry that SZ-102 reacted selectively with human granulocytes, monocytes, and with their bone marrow precursors, while human lymphocytes and red blood cells remained negative. In addition, SZ-102 antigen was expressed on themacrophage of liver, lung, thymus gland, spleen, lymph node by immunohistochemical SP methods, but amygdalae, thyroid gland, adrenal gland, brain, small intestine, colon, gastrics and skin were negative. It is suggested that MoAb SZ-102 is mainly against granulocytes. Immunoprecipitation demonstrated that molecular weight of polypeptidewas 20 kd under reducing condition.On the other hand, To evaluate the usefulness of 99Tcm labelled anti-granulocytemonoclonal antibody (MoAb) SZ-102 for the detection of experimental inflammatory areas in rabbits. The murine SZ-102 against human granulocytes was produced and labelled with 99Tcm using 2-iminothiolane modification MoAb and 9Tcm -glucoheptonate(GH) transchelation method. The rabbit experimental models of inflammatory areas were prepared,through injecting with Tcm-SZ-102 by ear-edge vein.and then imaged by SPECT. Tcm labelled murine IgG was used as a negative control. The inflammatory areas in rabbits were clearly imaged at 2 to 4 hour after injection of 99Tcm-SZ-102, while the control team after injection of "TcMabelled murine IgG was negative. Radiolabelled antibody was cleared from the blood with T1/2. of 0.10 + 0.04 h and TIQU of 3.19 + 0.41 h for SZ-102. The ratio of inflammtory muscle to blood was 0.22 + 0.02,while The ratio of normal muscle to blood was 0.02+0.01 after sacrifice. In a conclusion the MoAb SZ-102 may be a potential agent for the diagnosis and localization of inflammatory areas of carcinomas and clinically concealed infectious diseases.The value of this MoAb in human patients needs to be evaluated in clinical trials.