Biomphalaria; hemolymph cells; phagocytosis
RESEARCH NOTE
Effect of Biomphalaria straminea Plasma in the Phagocytosis of Biomphalaria glabrata Hemolymph Cells
Vol. 93, Suppl. I: 301-302
Elizabeth Malagueño*, Cecília Albuquerque, Célia MMB de Castro*, Morgana Gadelha, João Inácio Irmão*, José Valfrido Santana**/+
Laboratório de Imunopatologia Keizo Asami *Departamento de Medicina Tropical **Departamento de Biofísica,Universidade Federal de Pernambuco, Cidade Universitária, 50670-420 Recife, PE, Brasil
Key words: Biomphalaria - hemolymph cells - phagocytosis
RESEARCH NOTE
Mollusc defensive system that discriminates self from non self molecules, include fixed cells that can trap particles like endothelial cells, reticular and pore-cells, and circulating elements (WPW Van Der Knaap & ES Loker 1990 Parasitol Today 6: 175-182). Hemocytes, cells with phagocytic capacity, are determinant elements in the resistance or susceptibility of Biomphalaria snails to the trematoda Schistosoma mansoni infection (FS Bezerra et al. 1997 Rev Inst Med Trop S Paulo 39: 197-201). Biomphalaria resistance or susceptibility to S. mansoni infection is well defined as genetically determined (JV Santana et al. 1978 Rev Saúde Públ S Paulo 12: 67-77). Allograft of producing amebocyte organ from resistant snails to susceptible ones, enhance its resistance suggesting that the phenomenon is dependent on hemocytes activity (JT Sullivan et al. 1995 J Parasitol 5: 829-33). On the other hand, inoculation of hemolymph from B. tenagophila infected with either S. mansoni or with other trematoda furcocercaria, raised significantly the cellular response of susceptible mollusc (SM Reis et al. 1995 Rev Saúde Públ 29: 259-264).
Susceptible B. glabrata snails hemocytes made phagocytosis more efficient when latex particles were covered with resistant strains plasma. Furthermore, the results from our laboratory showed that B. straminea, a highly resistant mollusc to S. mansoni infection, is the only parasite host found in many endemic areas of northeast Brazil [FF Amâncio et al. 1989 Mem Inst Oswaldo Cruz (Suppl. I) 84: 253]. Therefore we tried to observe the influence of soluble products from B. straminea plasma in the phagocytic capacity of B. glabrata hemocytes.
B. glabrata hemocyte monolayer was prepared from hemolymph, collected through cephalo-podal bleeding and incubated at 22°C during 40 min in humid chamber. After washing, to remove non adherent cells, the monolayers were incubated with 105 cells of yeast (Saccharomyces sp.) for 1 hr at 22°C.
The slides were washed to detach non ingested yeast, fixed with methanol and stained with Giemsa. For determination of the phagocytic index, 200 cells per slide were counted.
When necessary, B. straminea plasma was previously incubated with the yeast suspension for 1 hr at 22°C. Another procedure was carried out using the plasma previously warmed at 56°C during half an hour (plasma 56). Following this schedule, five groups were done:
Group A: monolayer + fresh B. straminea plasma + yeast suspension
Group A 56: monolayer + B. straminea plasma 56 + yeast suspension
Group B: monolayer + incubated fresh plasma + yeast suspension
Group B 56: monolayer + incubated plasma 56 + yeast suspension
Group control: monolayer + Hanks + yeast suspension.
Analysis of the results of the Tukey test (Table), led us to conclude that the incubation with B. straminea plasma raises significantly the phagocytic capacity of B. glabrata hemocyte. Previous incubation of yeast with plasma, does not facilitate the uptake of the yeast, on the contrary, there was a decrease of phagocytosis. The enhacing effect of plasma is temperature dependent, decreasing significantly after half an hour at 56°C.
These results strongly suggest that soluble and termosensible products present in the B. straminea plasma, increase the phagocytic capacity of susceptible B. glabrata to Saccharomyces sp. yeast.
This work was supported by Finep (Grant no. 66920454000).
+Corresponding author. Fax: +55-81-271.8485. E-mail: JVal@lika.ufpe.br
Received 4 May 1998
Accepted 31 August 1998
Publication Dates
-
Publication in this collection
14 July 2000 -
Date of issue
1998
History
-
Accepted
31 Aug 1998 -
Received
04 May 1998
