DNA immunization: effect of secretion of DNA-expressed hemagglutinins on antibody responses

DNA vaccines expressing plasma membrane and secreted forms of the influenza and measles virus hemagglutinins (HAs) have been used to evaluate the effe ct of secretion on DNA-raised antibody responses. At low doses of DNA, the plasma membrane form of the influenza virus HA raised higher titers of anti body than the secreted form. The isotype of the DNA-raised antibodies depen ded on both the method of DNA delivery and the form of the expressed antige n. Following intramuscular injections, DNAs expressing membrane bound forms of the influenza and measles HAs raised predominantly IgG2a. By contrast, DNAs expressing the secreted from of the two HAs as well as another secrete d protein. human growth hormone, raised predominantly IgG1. Gene gun delive ry resulted in predominantly IgG1 antibody responses for both secreted and membrane bound forms of the hemagglutinins. The raising of predominantly Ig G1 by i.m, delivery of the secreted form of the influenza hemagglutinin was IL-4 dependent suggesting that a T-helper 2-biased immune response had bee n raised. (C) 1999 Elsevier Science Ltd. All rights reserved.