MHC class II engagement inhibits CD99-induced apoptosis and up-regulation of T cell receptor and MHC molecules in human thymocytes and T cell line.
Major histocompatibility complex (MHC) class II surface levels on thymocytes increase after CD99 ligation. The functional implication of the up-regulated MHC class II was assessed by engaging MHC class II on CD99-ligated cells. MHC class II engagement down-modulated surface levels of T cell receptor and MHC molecules, and inhibited apoptosis of CD99-ligated thymocytes and CEM tumor cells, antagonistic effects on the previously reported CD99 functions. The results were reproducible regardless of the order of ligation of MHC class II and CD99. We suggest that signaling via MHC class II on CD99-engaged cells might be involved in the thymic maturation process by damping CD99 ligation effects.
Kim
Min Kyung
MK
Department of Pathology, College of Medicine, Seoul National University, Yongun-dong 28, Chongro-gu, Seoul 110-799, South Korea.
Choi
Yoon-La
YL
Kim
Min Kyung
MK
Kim
Seok-Hyung
SH
Choi
Eun Young
EY
Park
Won Seo
WS
Bae
Young Mee
YM
Woo
Sang Kyu
SK
Park
Seong Hoe
SH
D000071443:12E7 Antigen; D015703:Antigens, CD / Q000502:physiology*; D017209:Apoptosis / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000502:physiology*; D002460:Cell Line; D015536:Down-Regulation; D005434:Flow Cytometry; D000949:Histocompatibility Antigens Class II / Q000502:physiology*; D006801:Humans; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*; D015854:Up-Regulation
D000071443:12E7 Antigen; D015703:Antigens, CD; C061828:CD99 protein, human; D015815:Cell Adhesion Molecules; D000949:Histocompatibility Antigens Class II; D011948:Receptors, Antigen, T-Cell