Cloning and functional expression of the T cell activation antigen CD26.
A cDNA encoding the T cell activation Ag CD26 was isolated from human PHA-activated T cells by using an expression cloning method. The nucleotide sequence obtained predicts a protein of 766 amino acids of type II membrane topology, with six amino acids in the cytoplasmic region. The predicted amino acid sequence of the Ag was 85% homologous to that of the dipeptidyl peptidase IV enzyme isolated from rat liver. Derivatives of the human leukemic T cell line Jurkat transfected with a CD26 expression plasmid were established. Characterization of the CD26 Ag expressed by the transfected Jurkat cells revealed that the Ag could be immunoprecipitated as a 110-kDa molecule similar to that found on peripheral blood T cells and that the Ag had dipeptidyl peptidase IV activity. Functional analysis of these Jurkat transfectants showed that cross-linking of the CD26 and CD3 Ag with their respective antibodies resulted in enhanced intracellular calcium mobilization and IL-2 production. These results provide direct evidence that the CD26 Ag plays a role in T cell activation.
Tanaka
T
T
Division of Tumor Immunology, Dana-Farber Cancer Institute, Boston, MA 02115.
Camerini
D
D
Seed
B
B
Torimoto
Y
Y
Dang
N H
NH
Kameoka
J
J
Dahlberg
H N
HN
Schlossman
S F
SF
Morimoto
C
C
D000595:Amino Acid Sequence; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis* / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004247:DNA / Q000302:isolation & purification; D018819:Dipeptidyl Peptidase 4; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D008213:Lymphocyte Activation; D008969:Molecular Sequence Data; D014162:Transfection
D000945:Antigens, Differentiation, T-Lymphocyte; D007376:Interleukin-2; D004247:DNA; D018819:Dipeptidyl Peptidase 4; D002118:Calcium