3.3 pCIgD-Man-L increased specific BoHV-1 antibodies titers in
cattle
Cattle received vaccination at 0, 30 and 60 days. When antibody kinetics
was evaluated, pCIgD and pCIgD-Man-L were able to induce specific
anti-BoHV-1 antibody levels (Fig.3a ). However, significant
differences in pCIgD-Man-L at 60 dpv (p<0.05) were found
compared with pCIgD group. After challenge assays (90 dpv) all animals
seroconverted (data not shown).
In addition, ELISA isotype titer at 90 dpv against BoHV-1 was analyzed
(Fig. 3b ). Interestingly, there were significant differences in
IgG1 (p<0.001) for the pCIgD and pCIgD-Man-L group versus
pCIneo, but in IgG2 difference was observed only for pCIgD-Man-L
(p<0.05) with respect to the pCIneo group.
No significant differences among groups were found when neutralizing
antibodies were measured; however, a trend of increasing neutralizing
antibodies was observed in pCIgD-Man-L over pCIgD treated groups (data
not shown).
Antibodies in nasal swabs were also evaluated. It is reported that the
presence of antibody in nasal mucosa confer protection against
respiratory viral penetration. Here, IgA isotype anti-BoHV-1 level in
nasal swabs at 6 days post challenge (dpc) was evaluated (Fig.
3c ). The results showed that the IgA titer in swabs of the pCIgD-Man-L
treated group was significantly different compared with pCIneo treated
group (p<0.05).
pCIgD and Man-L induce Dendritic Cells Activation in
vitro
Dendritic cells are the major antigen presenting cell (APC) and are key
initiators of antiviral responses (Ludewig et al., 2000). They
endocitose, process and present antigens to naive T cells and act as
messengers between the adaptive and innate immune responses. Afferent
lymph dendritic cells (ALDCs) from bovine were used to elucidate if DNA
alone or with loaded targeted liposomes were able to positively modulate
dendritic cells. ALDCs were incubated in vitro with vaccines
pCIgD, pCIgD-Man-L (with or without LPS from Brucella ovis ) or
Man-L alone (with or without LPS from Brucella ovis ). CD40
surface molecules were significantly upregulated with respect to mock
for pCIgD (p<0.01), pCIgD-Man-L with (p<0.05) and
without LPS (p<0.01). Also, CD40 was upregulated positively
when treated with Man-L with LPS (p<0.001) but not with Man-L
without LPS. These results indicate that pCIgD alone and liposomes
including LPS can activate dendritic cells (Fig.4) .