Induced immunity against the mosquito Anopheles stephensi: reactivity characteristics of immune sera

This study shows the progression of immune responses in mice during five sequential immunizations with Anopheles stephensi mosquito extracts, characterized by ELISA, Western blot and immunohistochemistry. When exposed repeatedly to mosquito bites, control mice developed antibodies which reached titres of 1:10(5), reacted weakly in Western blot analysis and were localized to the salivary glands. Mice immunized with mosquito head plus salivary glands, midgut, ovary, fat body, midgut microvilli (Mv) and midgut basolateral plasma membrane (Blm), showed increased titre with each successive boost. Epitopes were shared between sera or were specific to the immunizing or heterologous extract. Anti-Mv and Blm sera recognized proteins labelled by anti-midgut serum and gave specific reactions with the midgut and head. Cross-reactivity was confirmed immunohistochemically.