ULTRASTRUCTURE OF THE IMMUNE RESPONSES OF <I>ANOPHELES QUADRIMACULATUS</I> TO <I>ROMANOMERMIS CULICIVORAX</I> (NEMATODA: MERMITHIDAE) INFECTION
Keywords:Culicidae, granulocyte, hemocyte, host-parasite relationship, mosquito, nematode, plasmatocyte, prohemocyte, surface coat, transmission electron microscopy
AbstractShamseldean, M. M., E. G. Platzer, and R. Gaugler. 2006. Ultrastructure of the Immune Responses of Anopheles quadrimaculatus to Romanomermis culicivorax (Nematoda: Mermithidae) Infection. Nematropica 36:243-249. The ultrastructure of the early immune response of Anopheles quadrimaculatus larvae to invasion by the mermithid nematode Romanomermis culicivorax was examined in experimental infections. Host hemocyte recognition of R. culicivorax began immediately after infection. Cellular encapsulation and premelanotic reactions were noted. The proportions of plasmatocytes and especially granulocytes increased with hemocytes or their products adhering to invading nematodes within minutes of infection. Degranulation of granulocytes occurred when the host recognized the nematode surface, although contact between the hemocyte and the parasite was not required for recognition. Concurrently, the parasitic nematodes shed a dispensable sheet-like surface coat that intermittently interrupted the encapsulation process by serving as a physical barrier against the host immune system.