Characterization ofEncephalitozoon hellem(Microspora) isolated from the nasal mucosa of a patient with AIDS
SUMMARYA microsporidium of the genusEncephalitozoonwas isolated into culture from the nasal epithelium of a patient with AIDS. It was compared within vitroisolates ofEncephalitozoon cuniculiand the type isolate ofEncephalitozoon hellemby SDS–PAGE and by Western blotting with murine antisera raised toE. cuniculi, E. hellemand the nasal isolate, monoclonal antibodies raised toE. cuniculiand sequential sera from the patient. All tests showed similarities betweenE. hellemand the nasal isolate but differences between these two isolates andE. cuniculi. Minor protein differences betweenE. hellemand the nasal isolate were not considered sufficient to separate them at the specific level. The new isolate is named the Wainwright isolate ofE. hellem. The ultrastructure of the Wainwright isolatein vitrowas similar to that of the parasitein vivobut there was a greater tendency for disruption of the parasitophorous vacuoles. The deposition of the electrondense surface coat on the sporogonic stages ofE. hellem, as a uniform layer which later thickens, is in contrast to its deposition as broad bands, which later join up, inE. cuniculi. This may be a useful character in distinguishing the species without recourse to analysis of protein profiles.