Postvaccination Accumulation of the Influenza Virus Antigen in the Rat Choroid Plexus

Abstract

We examined the accessibility of influenza virus and diphtheria-tetanus toxin (DiTe) antigens to the choroid plexus (CP) within the postvaccination period and the expression of CD11b molecules (by immunohistochemistry). Eighteen Dark Agouti (DA) rats were divided into three groups: (i) animals administered with influenza vaccine (Flu), (ii) animals administered with DiTe vaccine (DiTe), and (iii) nontreated (Contr) animals. The serum antibody titers following influenza and diphtheria-tetanus vaccination were detected by the ELISA test. Immunohistochemical staining revealed a great number of viral antigen-positive and CD11b-positive brain cells in Flu rats compared to a very small number of the respective cells in DiTe animals and no staining in the Contr group. DiTe- and Flu-rats showed significant increases in the serum anti-tetanus toxoid and anti-influenza virus antibody levels compared to those in the Contr group. The results obtained attract attention towards the dynamic role of the CP in the immunosurveillance of the CNS. Based on the viral antigen deposits accumulated in the CP, it has been proposed that the latter can play an active role in modulation of the immune response after influenza vaccine immunization.