WESTERN-BLOT AND IMMUNOFLUORESCENCE ANALYSIS OF A HUMAN ISOLATE OF ENCEPHALITOZOON-CUNICULI ESTABLISHED IN CULTURE FROM THE URINE OF A PATIENT WITH AIDS

Microsporidia spores, identified as Encephalitozoon cuniculi (CDC:V282 ), were isolated from the urine of a patient with acquired immunodefic iency syndrome and disseminated microsporidiosis, established in conti nuous culture on monkey kidney cells (E6), and antiserum was produced in rabbits. Immunoblot studies that used the patient serum and the rab bit sera against CDC:V282, Encephalitozoon hellem (CDC:0291:V213), and Encephalitozoon intestinalis (CDC:V297) revealed that CDC:V282 and th e rabbit isolate of E. cuniculi (ECLD) reacted intensely with the pati ent's serum and the rabbit anti-CDC:V282, producing a number of bands ranging from 200 to 15 kDa. By contrast, the heterologous antigens (CD C:0291:V213 and CDCV297) reacted minimally. Both CDC:V282 and ECLD iso lates of E. cuniculi reacted minimally with the rabbit anti-E. hellem and the rabbit anti-E. intestinalis sera. In the immunofluorescence te st, performed on the lung biopsy section of the patient, the rabbit an ti-CDC:V282 serum reacted extensively with the spores in the tissue se ction and produced bright apple green fluorescence. These studies demo nstrated that the human (CDC:282) and the rabbit (ECLD) isolates of E. cuniculi were similar in their antigenic profiles but differed consid erably from E. hellem and E. intestinalis, and that the patient's seru m reacted specifically, strongly, and with equal intensity, with the 2 isolates of E. cuniculi.