Direct immunofluorescent staining of Leucocytozoon caulleryi of different developmental stages.

Direct immunofluorescence was first used successfully for the staining of Leucocytozoon caulleryi of different developmental stages, such as the 2nd generation schizont and merozoite, gametocyte, zygote, ookinete, and sporozoite. Fluorescent antibody of IgG nature prepared from sera of chickens over a period from the 21st to the 100th day after sporozoite inoculation was used in this experiment. The cross reactivity on different developmental stages of L. caulleryi in the direct fluorescent antibody test suggested that antigens common to different developmental stages, or shared antigens, might exist, as well as specific antigens so far well-known. The fluorescent intensity of oocyst sporozoite, and schizont contents was apparently lower than that of any other stage. This evidence might be elucidated by the antigenic incompletion.