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. Author manuscript; available in PMC: 2014 Apr 21.
Published in final edited form as: J Immunol. 2008 Dec 1;181(11):7639–7648. doi: 10.4049/jimmunol.181.11.7639

Figure 1. CD28 recruitment to the IS requires ligand binding.

Figure 1

A and B, Conjugates between DO11.10 TCR transgenic, CD4+ T cells (CD28+/+) or retrovirally transduced CD28KO T cells expressing a CD28-CFP fusion protein (CD28-CFP) and Ag-pulsed APC were analyzed base on their ability to recruit CD28 to the IS. CD80- APC are ProAd-ICAM cells that express MHC class II and ICAM-1, but not CD80 or CD86; while CD80+ APC are ProAd-ICAM-B7 cells that express MHC class II, ICAM-1 and CD80. CD28+/+ T cells were stained with αCD28 to label endogenous CD28, while localization of CD28-CFP was determined by CFP fluorescence. Representative images (A) and % of conjugates that recruit CD28 to the IS (B; n = 50 to 65 conjugates) from one experiment representative of two (CD28-CFP) or three (CD28 +/+) are shown. C and D, T cell conjugates with Ag-pulsed ProAd-ICAM-B7 APC were formed in the presence of 2 μg/ml mAb against CD80 (αCD80) or MHC class I (αMHC I) and analyzed for recruitment of CD28 to the IS. Representative images (C) and % of conjugates that recruit CD28 to the IS (D, n = 50 to 65 conjugates) from one experiment representative of three is shown. In all the images, the T cell is oriented toward the top in each panel. * p<0.0001 by two population proportion Z-student statistical test.