Abstract: six types of cells have been studied by means of indirect immunofluorescence staining method,using four kinds of human CREST scleroderma autoimmune antikinetochore serum which were separately taken from Shanghai,Beijing,the United States of America.The six types of cells are Hep-2 cell strain from human laryngeal carcinoma,the bone marrow cells of Gekko swinhonis,the bone marrow cells of Bufo bufo,CIK cell line from the kideney of Ctecopharyngodon idellus,C6/36 cell strain of Aedes albopictus,the root apical cells of Allium cepa L.The four kinds of serum were found to display discrete spots in all six types of cells by immunofluorescence.The number of spots per cell corresponds to the chromosome number in the cell types observed.In Hep-2 cells,the spots only exist in the kinetochore region of mitotic chromosomes,and each chromosome has two fluorescent spots.The results reveal that the kinetochore antigen preserves high conservation in evolution,and it possesses similar antigenicity in mammalian,reptilian,amphibian,fish,insectan and plant cells.The significance of the extensive conservation have been also discussed.In addition,the nature of the kinetochore antigen has been studied.The results of cytochemical analysis show that the antigen possesses complete similar antigenic nature in Hep-2 cells and the bone marrow cells of Bufo bufo.The kinetochore antigen is tightly bound non-histones.Its site (s) sensitive to proteslytic enzymes is (are) not exposed to outside,it is not complexed with DNA or RNA and is not extracted by 4M Urea/2M NaCI,it is risistant to 0.1M HCI,0.07M NaOH,but is partly destroyed by acetic acid.Finally,the methods taken in this study may be directly used to detect antikinetochore antibody in clinical diagnosis,so the study have some practical significance.