Five groups of 32 chemicals were examined regarding their immunological functions as modifier inactivants to make inactivated Sendai nasal
vaccine using a contact exposure experiment, direct immunofluorescent method, and serum HI titer. (1) Five of the nine reactive groups of reactive
dyes (2-chloropyridine, 2, 4, 6-trichloropyrimidine,
vinylsulfonic acid,
epichlorohydrin and beta-chloroethylamine) induced complete or almost complete defense in the entire respiratory tract, and the four other
vaccines brought about slight
infection in the respiratory tracts. There was no marked rise in serum HI titers post-exposure, despite uneven development. (2) Of the four sizable substituted AS
naphthol vaccines,
naphthol AS-IRG and AS-G
vaccines elicited nearly complete defense, but the two other
vaccines, inactivated with more elongated molecules, invited rare and successive
infections. The three immune groups produced invariably high serum HI titers. (3) Of the six
naphthalene derivative
vaccines, two (3-hydroxy-2-naphthoic acid methylester and 2-naphthol-6-sulfonic acid) induced complete or almost complete protection. But two
vaccines brought about less protection, and the remaining two
vaccines caused heavy
infections. (4) Of the six
benzene derivative
vaccines, both m-nitrobenzenesulfonic
acid and
isatoic anhydride induced complete protection. Three
vaccines permitted slight
infections but 2, 4, 6-trinitrobenzenesulfonic
acid vaccine caused severe
infection. (5) Of the seven food
dye vaccines, only orange I induced complete or nearly complete defense, while the other
dye vaccines were inferior. In effect, twelve inactivated Sendai nasal
vaccines modified the
ribose and/or
phosphate groups of the virus core
RNA through five groups of small-sized molecules with specially fixed side chains, and elicited complete or almost complete respiratory mucosal defense. The viral stabilization requiring the least alteration of the configuration will be involved in the chemical modification.