Phenotypic characterization and analysis of allogeneic T cell responses in ZAP-70 dominant negative transgenic mice.
Antigen stimulation of T cells results in a series of biochemical events including the interaction of both SH2 domains of ZAP-70 with phosphorylated ITAMS on the T cell receptor. In order to study the physiological relevance of decreasing native ZAP-70-SH2 interaction in vivo, we generated transgenic mice expressing a T cell-specific, dominant negative form of ZAP-70 consisting of only the tandem SH2 domains (ZAP-NC). Phenotypically, these animals had a comparable distribution of lymphocyte subsets in the thymus and spleen compared with the wild-type (WT) controls. However, examination of peripheral blood revealed a slow but progressive decrease in the number of lymphocytes, particularly CD4+ cells, with age (17% reduction by 3 months, 58% reduction by 6 months). Allogeneic responses were then evaluated in vitro as well as in vivo using a subcutaneous sponge matrix implant. Although spleen cells cultured for 4 days in vitro with alloantigen developed normal functional responses, allogeneic responses generated in vivo within a subcutaneous sponge matrix were impaired. This was characterized by a depression in cytotoxic T lymphocyte (CTL) activity, a 82% reduction in the frequency of helper T cells, and a 78% reduction in the capacity of sponge-infiltrating lymphocytes to produce IL-2 in response to secondary antigen stimulation. These results indicate that although overt lymphocyte development and in vitro function were unremarkable, expression of a truncated ZAP-70 affected the in vivo survival of peripheral lymphocytes and altered the in vivo generation of functional activity to alloantigen.
Gladue
R P
RP
Central Research Division, Pfizer, Inc., Groton, CT 06340, USA.
Allen
M
M
Cunningham
A
A
Gardner
J
J
Laquerre
A M
AM
Connelly
P A
PA
Shaw
A S
AS
Mcneish
J
J
D000818:Animals; D016130:Immunophenotyping; D007376:Interleukin-2 / Q000096:biosynthesis; D051379:Mice; D008822:Mice, Transgenic; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*; D051746:ZAP-70 Protein-Tyrosine Kinase
D007376:Interleukin-2; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497262:Zap70 protein, mouse