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In vitro effect of 5G8‐specific antibodies on Giardia lamblia trophozoites
Author(s) -
Rascon Raul,
Dominguez Victor,
Garzon Thania,
Samaniego Brenda,
Valdez Alejandra,
Quintero Jael,
Rascon Lucila,
Velazquez Carlos
Publication year - 2018
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2018.32.1_supplement.lb592
Subject(s) - polyclonal antibodies , giardia lamblia , biology , antibody , monoclonal antibody , in vitro , microbiology and biotechnology , population , giardia , immunology , biochemistry , medicine , environmental health
Giardiasis is one of the most common gastrointestinal diseases worldwide, caused by the protozoan parasite Giardia lamblia . Although several immunogenic proteins of the parasite have been identified, the capacity of inducing a protective humoral response has been scarcely evaluated. Our research group have identified and characterized the immunogenic 5G8 protein, a 70 kDa Variant‐specific surface protein (VSP). The administration of 5G8‐specific monoclonal antibodies (AcMo 5G8.B5) to infected animal decreased the parasite intestinal load. The aim of the present study was to evaluate the in vitro effect of 5G8 specific antibodies on G. lamblia trophozoites. We isolated 5G8 protein by passive elution from SDS‐PAGE (membrane protein enriched fraction of trophozoites lysates). C3H/HeJ mice were intraperitoneally immunized with isolated 5G8 protein to generate polyclonal antibodies. GS/M‐83‐H7 5G8 (+) trophozoites were incubated with monoclonal and polyclonal antibodies specific to the 5G8 protein, and their agglutination capacity was evaluated. After 24, 48 and 72 hours incubation, cell proliferation was determinated and the expression of 5G8 protein on trophozoites was evaluated by Flow Cytometry. Polyclonal antibodies recognized 97 % of GS/M‐83‐H7 5G8 (+) trophozoite population, and a single band of 70 kDa (SDS‐PAGE). The AcMo 5G8.B5 and polyclonal antibodies had the ability to agglutinate G. lamblia trophozoites in vitro after 60 min of antibody exposure. Antibody treatments inhibited the in vitro G. lamblia growth. Isotype control antibody and preimmunized serum showed no inhibition of trophozoites proliferation. Surface 5G8 protein expression did not change during antibody treatments. Altogether, our data suggest a possible in vitro cytostatic effect of 5G8 specific antibodies on G. lamblia trophozoites. These findings put forward the capacity of the 5G8 protein to induce a protective humoral response against the infection. Support or Funding Information CONACYT: CB‐2010‐01/155224 This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .