The pleiotropic effects of certain growth factors may potentiate angiogenesis via a combination of direct effects on EC proliferation and migration and indirect effects that result in the generation of other potent EC mitogens from non-EC populations. The synergistic effects demonstrated when SF/HGF and VEGF are administered together in vitro may be reproduced in vivo by SF/HGF-induced upregulation of VEGF in vascular SMCs.

Abnormal proliferation of vascular smooth muscle cells (VSMCs) contributes to intimal hyperplasia during atherosclerosis and restenosis, but the endogenous cell cycle regulatory factors underlying VSMC growth in response to arterial injury are not well understood. In the present study, we report that downregulation of cyclin-dependent kinase 2 (cdk2) activity in serum-deprived VSMCs was associated with the formation of complexes between cdk2 and its inhib-

Transduction of dendritic cells (DC) can result in presenmixed lymphocyte reactions. Mice immunized with Adtation of tumor-associated antigens and induction of transduced DC develop cytotoxic T lymphocytes that are immunity against undefined epitopes. The present studies specific for the ␤-galactosidase or DF3/MUC1 antigens. demonstrate adenovirus (Ad)-mediated transduction of the The results also demonstrate that Ad.MUC1-transduced ␤-galactosidase gene in mouse DC. Similar transductions DC induce a specific response which inhibits the growth have been obtained with the gene encoding the of DF3/MUC1-positive tumors. These findings support the DF3/MUC1 tumor-associated antigen. We show that the usefulness of Ad-transduced DC for in vivo immunization Ad-transduced DC are functional in primary allogeneic against tumor-associated antigens. Results and discussionT cells. 1 Murine DC pulsed with peptides prime antigenspecific CD8 + cytotoxic T lymphocytes (CTLs) in vivo. 2 Flow cytometry was used to define the phenotype of DC Peptides derived from tumor-associated antigens have following transduction with recombinant adenovirus. DC similarly been used to pulse DC and induce antitumor derived from bone marrow expressed MHC class I and II immunity. [3][4][5] Other studies have employed soluble products, costimulatory molecules and ICAM-1 18 (Figure tumor-associated antigens for loading DC and generating 1a). Transduction with Ad.␤gal resulted in a similar patantitumor activity. 6 Whereas peptides pulsed on to DC tern of antigen expression ( Figure 1a). Moreover, transmay dissociate from MHC molecules, CD34 + cells have duction with Ad.MUC1 was associated with DF3/MUC1 been retrovirally transduced to stably express antigens expression and little if any effect on cell surface levels of after differentiation to DC. 7,8 In contrast to pulsing, trans-MHC, costimulatory or adhesion molecules ( Figure 1a). duction of DC can result in longer term antigen presenThe Ad.MUC1-transduced DC exhibited a typical mortation and induction of immunity against undefined phology with veiled dendrites (Figure 1b). Staining with MHC epitopes. Thus, transduced DC may be effective in MAb M5/114 (anti-MHC class II) and MAb DF3 demonimmunizing against known tumor-associated antigens. strated expression of DF3/MUC1 by the transduced DC The human DF3/MUC1 glycoprotein is aberrantly (Figure 1b). Immunoblot analysis of the Ad.MUC1 transoverexpressed in breast and other carcinomas. 9 The DF3 duced DC confirmed DF3/MUC1 expression ( Figure 1c). protein is one member of the MUC1 family of carcinomaWhereas MAb DF3 detects glycosylated MUC1, the findassociated antigens that contain variable numbers of ing that MAb DF3-P reacts with an approximately 55 kDa highly conserved (G+C)-rich 60 base pair tandem protein in the transduced DC also provides support for repeats. 10,11 A C-terminal region includes a transmemdetection of the unglycosylated protein core 19 ( Figure 1c). brane domain that anchors the antigen at the cell sur-DC are potent stimulators ...