Long-term persistence of cellular immunity to Oka vaccine virus induced bypernasal co-administration with Escherichia coli enterotoxin in mice

A mutant of Escherichia coli enterotoxin induced cellular immunity to a liv e varicella vaccine (the Oka strain) as a mucosal adjuvant in mice, The per sistence of this cellular immunity was investigated. A commercially availab le live Oka vaccine virus and toxin were administered once simultaneously v ia the nasal route, in mice. Ten or 12 months later, a delayed-type hyperse nsitivity to the vaccine virus was detected by footpad test, but an antibod y neutralizing the varicella-zoster virus was not. When spleen cells from m ice immunized with the vaccine and toxin were re-stimulated by live vaccine in vitro, their thymidine uptake and IL-2 production were higher than thos e from mice immunized with the vaccine alone, but lower than those of splee n cells prepared from mice 2 months after nasal administration. Production of IL-4 in these cells, however, was not induced by re-stimulation in vitro . These results suggest that although humoral immunity for Oka vaccine viru s is only weakly induced by one co-administration of the vaccine and toxin, cellular immunity is induced and maintained over 1 year, though it decline s with age. The nasal administration of the vaccine and toxin might be effe ctive for maintaining cellular immunity to the varicella-zoster virus long term. (C) 2001 Elsevier Science Ltd. All rights reserved.