Immunocytochemical studies on several developmental stages of Dipetalonema viteae (Filarioidea)

The binding of antibodies to infective larvae (L3), eggs, uterine contents and blood microfilariae was demonstrated by light microscopy employing the peroxidase-antiperoxidase (PAP) method. Antigen-antibody reactions were located on the shell of filarial eggs as well as on the cuticle and the interior of L3 and microfilariae. Using sera from Meriones unguiculatus, Mastomys natalensis and golden hamsters infected with D. viteae obtained at 7, 14, 21 and 28 weeks p.i. it was observed that the intensity of the immunostaining on several developmental stages of the filariae decreased with increasing duration of infection. This effect was more pronounced in the case of M. unguiculatus and M. natalensis than in the case of golden hamsters. For detection of surface antigenicity the simple procedure of drying the test material on microscopic slides proved to be time saving and equally specific as compared to the embedding in Epon of the filarial stages and the successive preparation of semithin sections. However, embedded filarial stages presented more intensive immunostaining than nonembedded stages. Moreover, sections allowed to demonstrate antigen-antibody reactions on the cuticle as well as inside the body cavity of the stages.