Dmp. Filgueira et al., ISOTYPE PROFILES INDUCED IN BALB C MICE DURING FOOT-AND-MOUTH-DISEASE(FMD) VIRUS-INFECTION OR IMMUNIZATION WITH DIFFERENT FMD VACCINE FORMULATIONS/, Vaccine, 13(10), 1995, pp. 953-960
The IgG isotype response in Balb/c mice infected with E;MD I/ or immun
ized with different vaccine formulations using inactivated virus parti
cles as antigen was analyzed at various times post-inoculation. For th
is purpose an ELISA based on polyclonal antibodies for detection and q
uantification of mouse IgG isotypes with FMD virus (FMDV) specificity
was developed. Three immunomodulators, which have been shown to be ver
y effective in inducing strong and long-lasting antibody responses (Ba
hnemann, Arch. Virol. 1975, 47, 47-56; Polatnik and Bachrach, Appl. Mi
crobiol. 1964, 12, 368-376), were employed to formulate different vacc
ines using aqueous and oil vehicles: a water-soluble fraction of the c
ell wall of Mycobacterium sp., a purified extract of lipopolysacharide
from Brucella ovis and a synthetic lipoamide, Avridine. Infected anim
als between 14 and 60 days postinoculation (d.p.i.) showed responses d
ominated by IgG2b, followed by IgG1, IgG2a and IgG3, respectively. The
IgG3 isotype was the first, together with IgG1, to be elicited during
the first 7 days after infection, whereas no IgG3 activity was detect
ed in vaccinated animals at any time. With formulations including immu
nomodulators, persisting high levels of IgG2b (similar to those of inf
ected animals) were detected until 180 d.p.i., while with conventional
vaccines IgG2b responses were detected up to 60 dp.i. Animals vaccina
ted with formulations including these immunomodulators presented an au
gmented resistance to viral challenge at 210 d.p.i. in relation with t
hose immunized with conventional vaccines. The possible relationship o
f these differences in the isotype response and protection is discusse
d