Chemotactic response of Brugia pahangi infective larvae to jird serum in vitro

Abstract

The Brugia pahangi infective larval response to jird serum was studied using an agar plate assay. Larvae placed onto the agar remained at the same place for 60 min. Once the larvae were stimulated by serum, more than 95% oriented towards the serum and reached it within few minutes. This larval response was inhibited by an activator of phosphodiesterase (imidazole), adenylate cyclase inhibitors (SQ22536 and MDL-12330A) and protein kinase A inhibitor. An inhibitor of phosphodiesterase (IBMX), an activator of adenylate cyclase (forskolin) and an membrane permeant analogue of cAMP (8-bromo-cAMP), caused a number of larvae to move out from the inoculation area towards the other zones. To our knowledge, this is the first report of a chemotactic response by B. pahangi larvae to host serum. We conclude that B. pahangi larvae show a chemotaxic response to host serum, and that cAMP and cAMP dependent protein kinase are involved in the signal transduction.

In vitro chemotactic responses of Brugia pahangi infective larvae to sodium ions

“…Filariae are also skin-penetrating parasitic nematodes, and their infection of hosts involves a chemotactic response. Recent studies (Gunawardena et al, 2003;Kusaba et al, 2008) have suggested that mammalian sera contain a chemoattractant for B. pahangi L3. Since these studies, however, there has been little progress in investigations regarding the attractants of B. pahangi L3.…”

“…The procedure previously described by Gunawardena et al (2003) applied HBSS to the I-area where filarial L3 were inoculated ( fig. 1).…”

“…The chemotactic responses of filarial L3 to FBS and salts were measured on agar plates according to a modified method previously described by Gunawardena et al (2003). Briefly, a 35-mm Petri dish (Sumilon, Sumitomo Bakelite Co. Ltd, Tokyo, Japan) was filled with 2 ml of 0.6% (w/v) Noble agar (Difco Laboratories, Inc., Detroit, Michigan, USA) dissolved in hot deionized water (DW) and allowed to cool at room temperature.…”

“…A recent study (Gunawardena et al, 2003) revealed that the filarial L3 of Brugia pahangi, a skin-penetrating parasitic nematode, were highly attracted to the serum of Mongolian jird (Meriones unguiculatus). In addition, Kusaba et al (2008) showed that the sera derived from various mammals attracted filarial L3.…”

“…The objective of the present study was to investigate the chemotactic reactivity of sodium chloride for B. pahangi L3 using the modified method of Gunawardena et al (2003).…”