Induction of protective immune responses against Venezuelan equine encephalitis (VEE) virus aerosol challenge with microencapsulated VEE virus vaccine.
Venezuelan equine encephalomyelitis (VEE) virus, a member of the family Togaviridae, genus Alphavirus, causes disease in humans and equids. The virus is normally transmitted by the bite of an infected mosquito however, it can also be highly infectious by aerosol. The purpose of the present study was to determine the effectiveness of formalin-fixed, 60Co-irradiated VEE virus microencapsulated in poly DL-lactide-co-glycolide in inducing immune responses protective against aerosol challenge with virulent VEE virus. Balb/c mice were primed by subcutaneous injection of microencapsulated VEE virus vaccine, followed 30 days later by a single immunization with the same vaccine given via the oral, intratracheal (i.t.) or subcutaneous (s.c.) route. Mice boosted by the i.t. or s.c. route had higher plasma IgG anti-VEE virus levels than orally immunized animals. The responses in the former groups were similar in magnitude to those seen in mice primed and boosted by the i.t. route. Antibody activity was detected in bronchial-alveolar and intestinal washes, fecal extracts and saliva from immunized animals. The levels of IgG and IgA antibody activity in bronchial-alveolar wash fluids from mice boosted by the i.t. route were higher than those seen in animals immunized by the oral or s.c. route with the microsphere vaccine. Mice immunized with the microencapsulated VEE virus vaccine were protected from lethal VEE virus infection following aerosol challenge at approximately three months after the initial immunization. Mucosal immunization via the i.t. route appeared to be the most effective regimen, since 100% of the mice resisted aerosol challenge.
Greenway
T E
TE
Department of Microbiology, University of Alabama at Birmingham 35294, USA.
Eldridge
J H
JH
Ludwig
G
G
Staas
J K
JK
Smith
J F
JF
Gilley
R M
RM
Michalek
S M
SM
D000280:Administration, Inhalation; D000336:Aerosols; D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis; D001672:Biocompatible Materials; D002460:Cell Line; D004339:Drug Compounding; D016503:Drug Delivery Systems; D004666:Encephalitis Virus, Venezuelan Equine / Q000276:immunology*; D004685:Encephalomyelitis, Venezuelan Equine / Q000276:immunology / Q000517:prevention & control*; D004797:Enzyme-Linked Immunosorbent Assay; D018928:Immunity, Mucosal; D007115:Immunization Schedule; D007117:Immunization, Secondary; D007279:Injections, Subcutaneous; D019344:Lactic Acid; D051379:Mice; D008807:Mice, Inbred BALB C; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers; D013047:Specific Pathogen-Free Organisms; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D014765:Viral Vaccines / Q000008:administration & dosage* / Q000276:immunology
D000336:Aerosols; D000914:Antibodies, Viral; D001672:Biocompatible Materials; D011108:Polymers; D015164:Vaccines, Inactivated; D014765:Viral Vaccines; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid