Flow cytometry analysis of the circulating haemocytes from Biomphalaria glabrata and Biomphalaria tenagophila following Schistosoma mansoni infection

Abstract

Aiming to further characterize the haemocyte subsets in Biomphalaria snails, we have performed a detailed flow cytometric analysis of whole haemolymph cellular components using a multiparametric dual colour labelling procedure. Ethidium bromide/acridine orange fluorescence features were used to first select viable haemocytes followed by flow cytometric morphometric analysis based on the laser scatter properties (forward scatter-FSC and side scatter-SSC). Our findings demonstrated that B. glabrata (BG-BH, highly susceptible to S. mansoni) and 2 strains of B. tenagophila (BT-CF, moderately susceptible and BT-Taim, resistant to S. mansoni) have 3 major circulating haemocyte subsets, referred to as small, medium and large haemocytes. The frequency of small haemocytes was higher in BG-BH, while medium haemocytes were the most abundant cell-type in both B. tenagophila strains. Schistosoma mansoni infection resulted in early reduction of large and medium circulating haemocytes followed by an increase of small haemocytes. Although parasite infection induced haemocyte alterations in all Biomphalaria strains, the response was particularly intense in BT-Taim, the parasite-resistant snail. Interestingly, the trematode infection induces changes in haemocytes with less granular rather than in those with more granular profile. The results indicated that, in B. tenagophila of Taim strain, circulating haemocytes, especially the medium and high subset with less granular profile, are very reactive cells upon S. mansoni infection, suggesting that this cell subset would participate in the early parasite destruction observed in this snail strain.

Haematopoiesis in molluscs: A review of haemocyte development and function in gastropods, cephalopods and bivalves

“…In terms of haemolymph proportions, the large and medium haemocytes are almost equally numerous while small haemocytes are comparatively fewer [70]. B. glabrata and B. tenagophila haemocytes have also been categorized into three (large, medium and small) categories based on flow cytometric analysis [71]. Each category can also be divided into a low or high granular haemocyte based on side scatter.…”

Resistance of Biomphalaria glabrata 13-16-R1 snails to Schistosoma mansoni PR1 is a function of haemocyte abundance and constitutive levels of specific transcripts in haemocytes

“…Among known facts are that snail size can influence infectivity rates: some strains of B. glabrata are susceptible as juveniles but resistant as adults (Richards et al, 1992), and larger snails exposed to S. mansoni have lower infection levels than smaller snails of the same age (Niemann and Lewis, 1990). Circulating snail haemocytes play a key role in immune surveillance (Oliveira et al, 2010) and will migrate from the haemolymph into the tissues after parasitic infection (Noda and Loker, 1989; Martins-Souza et al, 2009; Barçante et al, 2012). This change is most intense in resistant snails in which larger haemocytes nearly disappear from the haemolymph, while small cells gradually increase (Martins-Souza et al, 2009).…”

“…Circulating snail haemocytes play a key role in immune surveillance (Oliveira et al, 2010) and will migrate from the haemolymph into the tissues after parasitic infection (Noda and Loker, 1989; Martins-Souza et al, 2009; Barçante et al, 2012). This change is most intense in resistant snails in which larger haemocytes nearly disappear from the haemolymph, while small cells gradually increase (Martins-Souza et al, 2009). Haemocytes are involved in parasite recognition (Negrão-Corrêa et al, 2012), a capability that involves carbohydrate-binding receptors on spreading haemocytes (Fryer et al, 1989; van der Knaap and Loker, 1990; Renwrantz and Richards, 1992; Johnston and Yoshino, 2001; Castillo et al, 2007; Martins-Souza et al, 2011; Mitta et al, 2012).…”

Hemocyte production in Biomphalaria glabrata snails after exposure to different Schistosoma mansoni infection protocols

“…Stumpf and 19 Gilbertson reported a twofold increase in the B. glabrata hemocyte count at 2 h after exposure to the miracidia. al ; there was an increase in the B. glabrata hemocyte count immediately following exposure to a smaller number of miracidia, which was followed by the peak of the cellular production on the third and fourth days and a marked decrease in the hemocyte counts on the sixth and the 21 seventh days. Martins-Souza et al characterized the live hemocytes present after schistosomal infection using a cytometric analysis and identified the peak hemocyte production to be 24 h post-infection.…”