CD1+ thymocytes proliferate and give rise to functional cells after stimulation with monoclonal antibodies recognizing CD3, CD2 or CD28 surface molecules.
The signal requirements for activation and proliferation of CD1+ thymocytes have been studied in order to define whether this immature cell population could function as mature T cells do. We found that CD1+ cells expressed high levels of CD25 antigen upon triggering with specific monoclonal antibodies (mAbs) (anti-CD3, anti-CD2, anti-CD28) in association with low doses of Phorbol-13-myristate-12-acetate (PMA). More interestingly, we described that in the presence of PMA CD1+ thymocytes proliferate upon stimulation with anti-CD28 mAb as well as with a pair of anti-CD2 mAbs, without the need of exogenous interleukin-2 (IL2), whereas they respond to anti-CD3 mAb only if exogenous IL2 was provided. Furthermore, CD1+ cells stimulated under optimal proliferative conditions, gave rise to cell populations capable of lysing natural killer (NK)-sensitive (K562) and NK-resistant (MEL 10, Daudi, EPA1) tumor target cells. These data strongly support the idea that CD1+ thymocytes, under appropriate stimulations, display some of the functional capabilities of mature T cells.
Istituto Scientifico San Raffaele, Milan, Italy.
M R
MR
Zocchi
F
F
Marelli
A
A
Poggi
D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000502:physiology*; D018949:Antigens, CD1; D000943:Antigens, Differentiation / Q000032:analysis*; D000945:Antigens, Differentiation, T-Lymphocyte / Q000502:physiology; D018801:CD2 Antigens; D018106:CD28 Antigens; D017252:CD3 Complex; D002455:Cell Division / Q000276:immunology; D002675:Child, Preschool; D015870:Gene Expression / Q000276:immunology; D006801:Humans; D007223:Infant; D008213:Lymphocyte Activation / Q000276:immunology*; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000502:physiology; D011971:Receptors, Immunologic / Q000502:physiology; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis; D013950:Thymus Gland / Q000166:cytology / Q000276:immunology*
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D018949:Antigens, CD1; D000943:Antigens, Differentiation; D000945:Antigens, Differentiation, T-Lymphocyte; D018801:CD2 Antigens; D018106:CD28 Antigens; D017252:CD3 Complex; D011948:Receptors, Antigen, T-Cell; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2