title: Trichobilharzia ocellata: Quantification of effects on haemocytes of the pond snail Lymnaea stagnalis by morphometric means.
abstract: To identify functionally different subpopulations, we quantified by morphometric means the spreading activity of circulating haemocytes of the pond snail Lymnaea stagnalis, recognized by monoclonal antibodies (5 surface and 5 cytoplasmic). The influence of snail age and of the different intramolluscan stages of the compatible avian schistosome Trichobilharzia ocellata on this activity were studied. The antibody-recognized cells could be separated into two groups, differing in their spreading activities. The probes detecting cytoplasmic markers recognized the majority of cells (78-95%). These were active (well spreading), differentiated cells. The surface probes recognized a smaller part (12-38%) of the total haemocyte population. These harmocytes were less active (less spreading), and were predominantly immature cells. The relative sizes of the antibody-detected subpopulations were not affected by snail age or infection with T. ocellata. The maximal size (planimetric area) attained after attaching to glass of all cells increased between day 0 (juvenile snails) and about 6 weeks post (sham) exposure and then decreased. Infection had little effect on the spreading activity of the more differentiated cells. The less differentiated cells showed a larger spreading activity when the parasite was present as mother sporocyst and also when the digestive gland area became colonized by growing daughter sporocysts.
authors.affiliation: Laboratory of Medical Parasitology, Faculty of Medicine, Vrije Universiteit Amsterdam, The Netherlands.
authors.forename: R I
authors.initials: RI
authors.lastname: Amen
authors.forename: J M
authors.initials: JM
authors.lastname: Baggen
authors.forename: E A
authors.initials: EA
authors.lastname: Meuleman
authors.forename: A
authors.initials: A
authors.lastname: Wijsman-Grootendorst
authors.forename: M E
authors.initials: ME
authors.lastname: Boon
authors.forename: P D
authors.initials: PD
authors.lastname: Bezemer
authors.forename: T
authors.initials: T
authors.lastname: Sminia