Submitted to: Clinical and Diagnostic Laboratory Immunology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/13/2004
Publication Date: 2/14/2005
Citation: Kjos, S.A., Jenkins, M., Okhuysen, P.C., Chappel, C.L. 2005. Evaluation of a recombinant oocyst protein (cp41) in the detection of cryptosporidium-specific antibodies. Clinical and Diagnostic Laboratory Immunology. 12:268-272. Interpretive Summary: Cryptosporidiosis is an intestinal parasitic disease of humans and animals caused by the protozoan parasite Cryptosporidium parvum. The disease is prevalent in the young because their immune system is not fully developed. The prevention of cryptosporidiosis in humans and animals will depend primarily on removing the parasite from drinking water because there are no approved drugs or practical disinfectants for destroying the parasite. Cryptosporidiosis also appears to be a widely under-reported disease due to the fact that clinical signs (e.g. diarrhea, muscle ache, fatigue) are often mistaken for bacterial or viral gut infections. The present study showed that a recombinant protein, termed CP41, from the surface of the C. parvum oocyst stage is recognized by serum antibodies from patients infected with the parasite. This work suggests that the an assay based on recombinant CP41 protein may supplant assays based on native C. parvum antigen.
Technical Abstract: Cryptosporidium is an important cause of diarrhea in developed and developing countries and its epidemiology is of interest. The methodologies used in the detection of Cryptosporidium-specific antibodies vary widely, which complicates comparison of results. This study assesses the performance of a Cryptosporidium recombinant protein (rCP41) in a serological assay as compared to a crude antigen preparation. The 41 kDa protein from the oocyst wall was previously cloned and expressed in Escherichia coli. Sera from 192 healthy adults from the Texas Medical Center (Houston, TX) were tested for anti-Cryptosporidium antibody reactivity using both the crude and recombinant antigen preparations in an enzyme-linked immunosorbent assay. IgG reactivity was highly concordant (88%, p<0.0001) between the two antigen preparations with 110 positive (57%) and 59 negative (31%) by both tests. Regression analysis revealed a high correlation between the absorbance values generated with both antigen preparations and suggests that the rCP41 may be used in place of crude antigen. These results indicate that the use of the recombinant CP41 antigen in a standardized serodiagnostic assay could provide a reliable and cost effective method for assessing human exposure to Cryptosporidium.