Infective process evaluation by Leishmania (L) Chagasi in the lull cell line, focusing on physicochemical and environmental variables

Abstract

The following research describes the evaluation in the in vitro infection by Leishmania (L.) chagasi in a Lulo cell line, resulting from Lutzomyia longipalpis embryonic tissue, taking into account physicochemical and environmental variables. The medium Gracel/L-15, containing 5% Fetal Bovine Serum (FBS), was used to maintain the cell strain Lulo. The infection process was performed by using Leishmania chagasi CLO44B/84 strain. The physicochemical variables of the growing medium evaluated for the experimental tests of the cell infection were: concentration of FBS (5%, 10%, 15%, and 20%), presence and absence of hemolinfa, pH (5. 5.5, 6. 6.5, and 6.8) and osmolality (35 400 y 450 mOsm/kg). In addition, the temperature which the infected cells were incubated (26°C, 32°C and 37°C) was also evaluated. As substrate for the infected cells, glass cover-slips of 12 mm of diameter in 24 well plates were used. The cover-slips with attached infected cells were removed after 3, 6, and 9 days post-infection. The Experimental observations showed that the greatest percentage of infection (33.3%), was obtained at the 5% FBS level, osmolality of 320 mOsm/Kg, a pH of 6.8 and an optimum temperature of 26°C. By selecting these parameters, high levels of infection were reached and these results will certainly be of great use in future studies and applications of the interaction vector-parasite-cells, in the perspective to contribute with leishmaniasis control.