Immunodominant proteins alpha-1 giardin and beta giardin are expressed in both assemblages A and B of Giardia lamblia.

RANOCCHIA R; FELIZIANI C; MERINO C; TOUZ MC; ROPOLO AS

Congreso; IX Congreso Argentino de Protozoología y Enfermedades Parasitarias.; 2011

To date, eight assemblages of Giardia lamblia have been described, but only assemblages A and B are known to infect humans. Despite the fact that the genomic, biological, and clinical differences found between these two assemblages has raised the possibility that they may be considered different species, there is relatively limited information on their phenotypic differences. In the present study, we developed monoclonal antibodies against ��-1 and �� giardin, two immunodominant proteins produced during G. lamblia infection, and studied their expression and localization in WB (assemblage A) and GS trophozoites (assemblage B). The polyclonal antibodies generated against WB trophozoites, particularly those recognizing intracellular proteins as well as the proteins present at the plasma membrane (variable-specific surface proteins), showed cross-reactivity with intracellular proteins in GS trophozoites. The use of monoclonal antibodies against �� giardin led to a ventral disc localization, particularly at the periphery in WB trophozoites. Interestingly, although �� giardin was also restricted to the ventral disc in GS trophozoites, the pattern of localization clearly differed in this assemblage. On the other hand, monoclonal antibodies against ��-1 giardin showed the plasma membrane localization in both assemblages which also occurred in the bare area of GS trophozoites. Moreover, the same localization at the plasma membrane was observed in Portland-1 (Assemblage A) and in P15 (Assemblage E) trophozoites. We found differences in the localization of the ��-giardin protein between assemblages A and B, but, on the other hand, we found the same pattern of localization of ��-1 giardin in strains from Assemblages A, B and E. These findings reinforce the need for more studies based on phenotypic characteristics in order to disclose how far one assemblage is from the other.Giardia lamblia have been described, but only assemblages A and B are known to infect humans. Despite the fact that the genomic, biological, and clinical differences found between these two assemblages has raised the possibility that they may be considered different species, there is relatively limited information on their phenotypic differences. In the present study, we developed monoclonal antibodies against ��-1 and �� giardin, two immunodominant proteins produced during G. lamblia infection, and studied their expression and localization in WB (assemblage A) and GS trophozoites (assemblage B). The polyclonal antibodies generated against WB trophozoites, particularly those recognizing intracellular proteins as well as the proteins present at the plasma membrane (variable-specific surface proteins), showed cross-reactivity with intracellular proteins in GS trophozoites. The use of monoclonal antibodies against �� giardin led to a ventral disc localization, particularly at the periphery in WB trophozoites. Interestingly, although �� giardin was also restricted to the ventral disc in GS trophozoites, the pattern of localization clearly differed in this assemblage. On the other hand, monoclonal antibodies against ��-1 giardin showed the plasma membrane localization in both assemblages which also occurred in the bare area of GS trophozoites. Moreover, the same localization at the plasma membrane was observed in Portland-1 (Assemblage A) and in P15 (Assemblage E) trophozoites. We found differences in the localization of the ��-giardin protein between assemblages A and B, but, on the other hand, we found the same pattern of localization of ��-1 giardin in strains from Assemblages A, B and E. These findings reinforce the need for more studies based on phenotypic characteristics in order to disclose how far one assemblage is from the other.