Xf. Csar et al., MONOCLONAL-ANTIBODY TO A THY-1 RELATED ASSOCIATED MOLECULE IDENTIFIESA SUBPOPULATION OF IMMATURE MOUSE THYMOCYTES/, Thymus, 22(3), 1994, pp. 125-140
In this study, NMT-1 mAbs have been shown to identify a thymocyte cell
surface molecule (Immature Thymocyte Marker-1, ITM-1) expressed on 86
.2 to 90.8% of CD4(+)CD8(+)CD3(-/lo/int) cells within the thymus of Ba
lb/c, CBA, C57B1/6, 129 Rej, A/J and AKR mice. Similarly, immunoprecip
itation analysis of cell membrane extracts from (125)Iodine-labelled t
hymocytes, using NMT-1mAbs, identified 14.5 and 18.3 kDa molecules fro
m all strains of mice examined. Comparison of these immunoprecipitatio
n profiles with those produced by rat IgG(2b) anti-Thy-1 antibodies in
dicated that NMT-1 mAbs recognized a subspecies of the Thy-1 molecule.
Unlike the Thy-1 molecule, the expression of ITM-1 molecules in Balb/
c, CBA, C57B1/6, 129Rej, A/J and AKR strains of mice was restricted to
the thymus. The ITM-1 molecule was not expressed on lymphoid cells wi
thin the spleen, lymph node, bone marrow, peritoneal cavity and periph
eral blood in these strains. Phenotypic characterization associated th
e expression of ITM-1 molecule with the CD4(+)CD8(+)CD3(-/lo/int) thym
ocyte subpopulation indicating that NMT-1 mAbs recognize an epitope on
a distinct developmentally-related Thy-1 glycoform. The expression of
the ITM-1 molecule on differentiating thymocytes may prove useful in
further subdividing immature thymic subpopulations, particularly those
implicated in positive and negative selection.