Humoral responses following immunization with Leishmania infantum (ex. Oklahoma): a comparison of adjuvant efficacy in the antibody responses of Balb-C mice.

Adjuvants are commonly used in immunization protocols for the purpose of augmenting immune responses to antigens. The antigenic profile of Leishmania infantum (ex. Oklahoma) is described and the efficacies of three adjuvants delivered coincidentally with killed promastigotes are compared, by measuring relative serologic responses of Balb-C mice to specific antigenic determinants. Western blotting techniques were employed to visualize humoral responses to isolated antigens; serologic profiles were compared and contrasted. Four immunization protocols utilizing Freund's complete adjuvant, glucan adjuvant, lipovant adjuvant or phosphate-buffered saline, in conjunction with killed L. infantum (ex. Oklahoma) promastigotes were executed in parallel. All groups receiving adjuvant protocols developed enhanced serologic responsiveness. Similar profiles were observed in mice treated with glucan or lipovant. Animals receiving promastigotes in Freund's complete adjuvant also developed strong humoral responses, binding cross-reactive epitopes not recognized by other groups. Our findings indicate that glucan and lipovant present effective adjuvant alternatives, to Freund's complete adjuvant and may be of value in immunization against visceral leishmaniasis.