Regulation of i- and I-antigen expression in the K562 cell line.
Expression of i- and I-antigen in K562 cultured under different conditions of culture was investigated. Under standard conditions of culture, i-antigen expression was very high (100% of i-labeled cells) in contrast to I-antigen expression of which was very low (2 to 5% of I-labeled cells). The addition of hemin to K562 cells did not modify the mean antigenic density or the proportion of i- and I-labeled cells. In contrast, sodium butyrate elicited an important increase in the proportion of cells exhibiting I-antigen associated to a decrease of i-antigenic density. The effect of butyrate was reversible and dependent upon de novo protein and messenger RNA synthesis since it was abolished in the presence of cycloheximide or actinomycin D. The stimulation of i-antigen conversion to I-antigen elicited by butyrate cannot be directly related to an induction of differentiation since evidence in this sense is lacking; in fact, butyrate did not increase the hemoglobin content of K562 cells. The passage from exponential to stationary phase of growth (cell density inhibition) was associated with an increase in I-antigen expression and a slight decrease in i-antigen density on the surface of K562 cells.
D000941:Antigens / Q000235:genetics*; D002087:Butyrates / Q000494:pharmacology; D020148:Butyric Acid; D002460:Cell Line; D002999:Clone Cells; D004261:DNA Replication; D005455:Fluorescent Antibody Technique; D006418:Heme / Q000494:pharmacology; D006454:Hemoglobins / Q000032:analysis; D006801:Humans; D007700:Kinetics; D007951:Leukemia, Myeloid / Q000276:immunology*
D000941:Antigens; D002087:Butyrates; D006454:Hemoglobins; D020148:Butyric Acid; D006418:Heme