Porphyrin content of the cysticercus of Taenia solium.

The strong red fluorescence of the cysticercus of Taenia solium depends on the presence of several porphyrins in the vesicular fluid of the parasite: probably protoporphyrin IX, coproporphyin I or III, and 2 decarboxylated porphyrins intermediate between uroporphyrin and coproporphyrin. Cyst porphyrins associated to form conglomerates of high molecular weight that dissociated in acid solutions and were not antigenic themselves nor associated with antigenic molecules. An appreciable fraction of the porphyrins was capable of undergoing oxidation and reduction, indicating that some of the porphyrins were complexed with metal ions. The metabolic basis for the accumulation of porphyrins is unknown. Preliminary results suggest that conditions deleterious to the cysticercus cause release of porphyrins so that the appearance of porphyrins in the cerebrospinal fluid of neurocysticercotic patients may prove useful in monitoring therapeutic attacks on the parasite.