Giardia lamblia native antigens

Giardia lamblia is a flagellated intestinal parasite of the protozoan kingdom. G. lamblia causes intestinal malabsorption and diarrhea (giardiasis) in humans and other mammals. A central factor behind Giardia’s success as a parasite is its simple, two-stage life cycle. After the host ingests the cysts (the infective stage), trophozoites appear in the duodenum and attach to the mucosa of the small intestine. Trophozoids divide mitotically within the intestine; some of them later turn into cysts and get out.
Countless evidence demonstrates the role of the humoral immune response in the elimination of G. lamblia. The dynamics of antibody concentrations are different for IgM, IgG and IgA. IgM levels increase significantly between 14 and 21 days postinfection and gradually decrease after therapy. In contrast, IgG levels remain elevated after successful treatment. The dynamics of IgA levels are similar to those of IgM. Serological testing is considered a useful adjunct to the diagnosis of giardiasis. In addition to aiding in diagnosis, it can be useful for understanding the state of a patient’s immune response and for epidemiological studies. To identify a specific immune response to Giardia lamblia, both native and recombinant antigens are used. About 16 different proteins found in both cysts and trophozoites are considered immunoreactive. Therefore, the use of a mixture of native antigens in immunoassays may have an advantage in terms of sensitivity.