Analysis of anamnestic immune responses in adult @entity1641 and priming in neonates induced by a DNA vaccine expressing the vapA gene of XXXX .

@entity5820 @entity16840 @entity1641 @entity55
@entity5820 remains one of the most important pathogens of early life in @entity1641 , yet conventional vaccines to prevent @entity55 have not been successful. DNA vaccination offers an alternative to conventional vaccines with specific advantages for immunization of neonates. We developed a DNA vaccine expressing the @entity16840 gene (pVR1055vapA) that induced an anamnestic response characterized by @entity16840 ( @entity16840 )-specific IgG antibodies in sera and bronchoalveolar lavage fluid (BALF) as well as @entity16840 -specific proliferation of pulmonary lymphocytes when tested in adult ponies. In contrast, none of the adults receiving the control plasmid responded. To determine if pVR1055vapA induced @entity16840 -specific responses in the foal, the targeted age group for vaccination against @entity5820 , 10 na  ve foals were randomly assigned at birth to two groups of five. At 8-15 days of age (day 1), foals were vaccinated by intranasal and intradermal (i.d.) routes with either pVR1055vapA or the negative control pVR1055vapA_rev. All foals were DNA boosted at day 14 and protein boosted at day 30 with either recombinant @entity16840 or recombinant CAT (control group). Prior to the protein boost, neither group developed @entity16840 -specific immune responses. However, at day 45, two of the VR1055vapA-vaccinated foals had increased titers of @entity16840 -specific IgGb, IgM and IgGa in the sera, and IgG in the BALF. The induction of the opsonizing isotypes IgGa and IgGb has been previously shown to be associated with protection against @entity5820 . No @entity16840 -specific immune responses were detected in the control group. This study indicates that the DNA vaccine effectively stimulates anamnestic systemic and pulmonary immune responses in adult @entity1641 . The results in foals suggest that the DNA vaccine also primed a subset of immunized neonates. These data support further development and modification to produce a DNA vaccine to more effectively prime neonatal foals.
