Levels of Tap-1 and Tap-2 mRNA and expression of Kd and Db on splenic lymphocytes are normal in NOD mice.
It has been reported that the level of Tap-1 (transporter associated with antigen processing) mRNA and the expression of class I on splenocytes are low in NOD mice. Class I expression at 37 degrees C depends on an adequate supply of peptides, so a decrease in Tap could lead to lower class I levels. Since hypoexpression of class I correlated uniformly with the development of diabetes, it has also been suggested that Tap-1nod is diabetogenic. However, others report normal Tap-1 and class I levels in NOD mice. We examined Tap-1 and Tap-2 mRNA levels in NOD/Smrf mice using a reverse transcriptase-polymerase chain reaction method that detects > or = 25% changes in mRNA. We also assessed class I expression with three monoclonal antibodies. No difference in Tap-1 or Tap-2 mRNA levels for females of different ages or between diabetic and nondiabetic animals was observed. Tap-1 mRNA levels were identical between NOD/Smrf and BALB/cJ mice. Kd expression was significantly lower on NOD lymphocytes than in BALB/cJ cells, but the difference was due to the smaller size of the NOD splenic lymphocyte. When cells of the same size were analyzed, no difference in class I levels was observed. Class I levels were also identical in diabetic and age-matched nondiabetic NOD and BALB/c females. Both NOD Tap-1 mRNA and class I were increased by interferon-gamma. We find no evidence for impaired NOD Tap gene activity or class I expression, as previously reported for this strain.
Pearce
R B
RB
Sansum Medical Research Foundation, Santa Barbara, CA 93105, USA.
Trigler
L
L
Svaasand
E K
EK
Chen
H M
HM
Peterson
C M
CM
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D005260:Female; D006183:H-2 Antigens / Q000378:metabolism*; D064532:Histocompatibility Antigen H-2D; D008214:Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism*; D013154:Spleen / Q000276:immunology / Q000378:metabolism
D000071181:ATP Binding Cassette Transporter, Subfamily B, Member 2; D000071450:ATP Binding Cassette Transporter, Subfamily B, Member 3; D018528:ATP-Binding Cassette Transporters; D017931:DNA Primers; D006183:H-2 Antigens; C024755:H-2K(K) antigen; D064532:Histocompatibility Antigen H-2D; D012333:RNA, Messenger; C073119:TAP1 protein, human; C486171:Tap1 protein, mouse; C489516:Tap2 protein, mouse; C071692:TAP2 protein, human