Mucosal administration of a non-toxic pseudomonas exotoxin-gpllo V3 loop chimera elevates gpllO specific IgG and IgA in the serum and saliva of balb/c mice

Our laboratories have been exploring the usefulness of a non-toxic form of Pseudomonas exotoxin (PE) as a delivery platform for the mucosal administration of an antigen. In the present report we describe IgA and IgG responses in the serum and saliva of mice dosed by various routes with a PE chimera which has had the Ib region of the molecule replaced with 26 amino acids of the V3 loop of HTV-1 MNgpl20. Female BALB/c mice (n=6/group) were dosed three times at two week intervals either orally (PO) with 40 jig or vaginally (V), rectaUy (R) or subcutaneously (SC) with 20 ug PE-V3 loop chimera. Six dosing regimens were used: PO/PO/PO; V/V/V; R/R/R; V/PO/PO; R/PO/PO; and SC/SC/SC. Serum and saliva samples taken at 30, 60 and 90 days after the initial immunization were analyzed by ELIS A for MNgpl20specific IgG and IgA content. After immunization, V3 loop-specific IgG was found in the sera of all groups with animals in the R/R/R, V/PO/PO and R/PO/PO groups having the highest serum tilers. At 90 days the SC/SC/SC group showed the greatest response. Rectal immunization with oral boosting showed consistently higher relative IgG titers than the other non-parenteral groups. Saliva samples from all groups except SC/SC/SC had saliva IgG concentrations higher than pre-immunization levels. Salivary IgA titers were greatest in the V/PO/PO group. These results indicate that both a mucosal and systemic immunologie response can be achieved by mucosal immunization with the PE-V3 loop sequence chimera.