Immune response during tumor therapy with antibody-superantigen fusion proteins.
To engineer superantigens (SAg) to express tumor reactivity, we genetically fused the Fab-part of the tumor-reactive MAb C215 and the bacterial SAg staphylococcal enterotoxin A (SEA). Treatment of mice carrying established lung micrometastases of the C215-transfected syngeneic B16 melanoma with 3-4 daily injections of C215Fab-SEA resulted in strong antitumor effects, while only moderate effects were seen when treatment was given every 4th day (intermittent treatment). High serum levels of IL-2, TNF-alpha, IFN-gamma and strong induction of CTLs (cytotoxic T lymphocytes) were noted after priming with the fusion protein. T cells responded well to 3 daily injections of C215Fab-SEA and then gradually entered a hyporesponsive state, characterized by a reduced ability to produce IL-2, TNF-alpha and IFN-gamma and failure to mediate cytotoxicity in vitro. Intermittent treatment was characterized by increased levels of IL-10, concomitant with accentuated loss of IL-2, TNF-alpha and IFN-gamma production. A 10-fold increase in SEA-reactive TCR V(beta)3+ CD4+ cells was observed in the spleen, while a loss of TCR V(beta)3+ CD8+ and V(beta)11+ CD8+ cells was noted. This is in striking contrast to injections of native SEA which induced a marked deletion of TCR V(beta)3+ CD4+ T cells, but not of CD8+ cells. Recovery of the TH1 cytokine profile occurred within 1-2 weeks, while restoration of cytotoxicity required several months and correlated with recovery of TCR V(beta)3+ CD8+ and TCR V(beta)11+ CD8+ T cells. These results show that the temporal relationship of SAg stimulations dictates the cytokine profile. Moreover, different mechanisms appear to regulate hyporesponsiveness in CD4+ and CD8+ T cells.
Pharmacia and Upjohn Inc., Lund, Sweden.
A
A
Rosendahl
J
J
Hansson
A
A
Sundstedt
T
T
Kalland
M
M
Dohlsten
D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics; D000951:Antigens, Neoplasm / Q000276:immunology; D004768:Enterotoxins / Q000276:immunology* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology / Q000627:therapeutic use; D007167:Immunotherapy; D008213:Lymphocyte Activation; D016393:Lymphoma, B-Cell; D008546:Melanoma, Experimental; D051379:Mice; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000276:immunology / Q000628:therapy*; D011993:Recombinant Fusion Proteins / Q000276:immunology*; D018089:Superantigens / Q000276:immunology* / Q000627:therapeutic use; D013601:T-Lymphocytes / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D004768:Enterotoxins; D007140:Immunoglobulin Fab Fragments; D011993:Recombinant Fusion Proteins; D018089:Superantigens; C026066:enterotoxin A, Staphylococcal