A Mechanism for Selective Recruitment of CD8 T Cells into B7-1-Transfected Plasmacytoma: Role of Macrophage-Inflammatory Protein 1α1

An important aspect of immunity is the recruitment and accumulation of lymphocytes into target tissues where Ags are localized. Because the TCR recognizes antigenic peptides presented by MHC molecules, the subset of T cells that exert effector function is determined by the class of MHC molecules expressed on a given tissue. We and others have demonstrated that CDS T cells are preferentially recruited into B7-1-transfected class II-negative plasmacytoma J558, and the virus-infected central nervous system. However, the mechanism for such specificity has not been addressed. Here we analyzed the mechanism for selective recruitment of CD8 T cells into B7-1-transfected plasmacytoma J558. We show that sustained accumulation of CDS T cells in vivo requires local expression of B7-1. In addition, we have observed a striking correlation between expression of macrophage-inflammatory protein 1α (MIP1α) and selective accumulation of CDS T cells in the tumors. The selective recruitment of CDS T cells is blocked by in vivo administration of neutralizing anti-MIP1α antisera. Moreover, gene-transfer studies reveal that locally produced MIP1α is sufficient to induce selective recruitment of CDS T cells. Taken together, our study reveals that costimulation by B7 leads to sustained local production of MIP1α, which selectively recruits CDS T cells into tumors. These results have important implications for T cell recruitment in vivo and for tumor immunotherapy.