Abstract
Purpose: :
To investigate the role of ocular inflammation in the early appearance of virus-specific neutralizing activity in tears.
Methods: :
Adult rabbits were immunized subcutaneously with poliovirus (PV) vaccine with Freund’s complete adjuvant (FCA) or adjuvant peptide (muramyl dipeptide, MDP). Ocular and systemic anti-PV neutralizing activity responses in tear and serum were determined. Tear immunoglobulins (Ig) were determined by western blot analysis to assess the ocular antibody responses. Topical MDP application was used to induce conjunctival inflammation.
Results: :
Serum antibody titers to PV (neutralization titers) in rabbits immunized with PV in the presence of FCA or MDP ranged from undetectable up to 3,000 units/ml over 14 d period. Anti-PV neutralizing activity was not detected in the post-vaccination tears (i.e., <20 units/ml). Monocular topical application of MDP acutely increased anti-PV neutralizing activity up to 10% of serum levels as well as the IgG/IgA levels in bilateral tears of immunized, but not un-immunized rabbits.
Conclusions: :
Subcutaneous injection of PV vaccine with FCA or MDP induced systemic anti-PV antibody responses, but anti-PV neutralizing activity was detected only in the tears of inflamed eyes. The results support the idea that induction of conjunctival inflammation in PV immunized rabbits significantly increases anti-PV neutralizing activity at the external ocular surface.
Keywords: conjunctivitis • immunomodulation/immunoregulation • pathobiology