Functional analyses of tumor DC-T cell interactions.
DCs-MB were purified from large MOPC315 or J558 tumors established in BALB/c mice. (A) Single-cell analysis of Ca++ mobilization in T cells that interact with DC-MB. Two fura-2 loaded T cells that interact with DCs-MB from MOPC315 are shown. Image 1: Light microscopic image of DCs before adding T cells. MBs are indicated by red arrows. Image 2-11: Pseudo-colored images of the cytosolic-free Ca++ concentration in T cells taken at different time points after addition of T cells to the wells. Image 12: Light microscopic image taken after the Ca++ registration, demonstrating the interaction between the 2 T cells (numbered and indicated by blue arrows) and DCs-MB (indicated by green arrows). T cell No. 1 evidently contacts 2 DCs-MB. An additional T cell (not numbered) came into the field after 242 seconds, has no contact with DC-MB, and is indicated by a blue arrow. Note that the T cells are smaller in the light microscopic images than in the pseudo-color images due to optical artifacts. (B) Ca++ traces of 2 different single T cells depicted in A. (C) Average Ca++ responses in cloned Id-specific Th1 7A10B2 cells stimulated by DC-MB from Id+ and Id− tumors in the presence or absence of synthetic Id peptide. Only cells with a response above 100 nM (ie, the threshold) are included. The responses were synchronized with a start of the signal set at 120 seconds. Number of analyzed-responding T cells: MOPC315 DC-MB, n = 81; J558 DC-MB, n = 39; and J558 DC-MB pulsed with λ2315 peptide, n = 28. (D) Frequency of responding T cells as a function of the magnitude of Ca++mobilization. Number of T cells analyzed: MOPC315 DC-MB, n = 280; J558 DC-MB, n = 229; and J558 DC-MB pulsed with λ2315peptide, n = 64. (E) Light microscopic images of cloned Id-specific T-cells 7A10B2, Th1 cultured for 2 days with DCs-MB from MOPC315 or J558 tumors.
