Antigenic analysis of Giardia duodenalis strains isolated in Alberta

Abstract

Giardia duodenalis is a common intestinal parasite in most parts of the world. In Canada it is associated with both endemic and epidemic infections that are often transmitted by the waterborne route. Although G. duodenalis strains have been isolated from several animals, the role of other mammals in human infection is unclear. We have isolated and cultured G. duodenalis trophozoites from domestic and wild animals in Alberta and compared them with a human isolate by protein gel electrophoresis and immunoblot analysis. All strains examined share a similar polypeptide profile and important protein antigens. Prominent antigens of 62, 52, 38, and 31 kilodaltons are conserved. The 52- and 31-kilodalton proteins are the major surface-exposed trophozoite components. The high degree of antigenic sharing among strains from different hosts suggests that there may be a wide range of potential reservoirs for G. duodenalis infections.

Analysis of proteins from membrane and soluble fractions of Giardia duodenalis trophozoites of two Brazilian axenic strains

“…In general, the electrophoretic patterns reported are complex and homogeneous, with the detection of multiple protein bands ranging from 140 to 10 kDa 21 , 122 to 10 kDa 2 or 250 to 14 kDa 24 . The overall homogeneity of the protein patterns is consistent with the results showed in previous investigations 2,7,21,24,25 that employed other strains. Heterogeneity has been observed in the 20-25 kDa and 50-56 kDa regions 7,26 .…”

“…Another point to be considered is that some proteins, glycoproteins and antigens detected in our study showed similar or close molecular masses to those of proteins associated with plasma membrane identified in early investigations 5,6,16,17,25 . In the present study, the method employed to obtain subcellular fractions of trophozoites did not allow the fractionation of plasma membrane proteins from those bound to the internal membranes.…”

“…The present study and early investigations have described a variety of antigenic proteins of Giardia duodenalis trophozoites like as those of 88, 82, 66, 62, 52, 38 and 30-34 kDa 2,5,6,7,25,26 . Among these antigens, the protein of 32 kDa have been recognized as an important component in a variety of strains 2,7,25,26 . CROSSLEY & HOLBERTON 3 detected a group of proteins associated with microtubules of ventral disc in the 30 kDa range that these authors termed giardins.…”

“…The complexity of protein fractions of Giardia duodenalis trophozoites has been reported by several authors 2,5,6,7,12,21,25 . In our study, Fig.…”

“…Considering that the composition and complexity of Giardia strains might be associated with aspects of the host-parasite relationship, characterization of trophozoites proteins from axenic strains have been conducted in order to expand the knowledge of this parasite and to detect differences between strains 2,5,6,7,12,21,25 . The proteins of trophozoites have been studied in terms of their localization and with respect to their nature and properties.…”