Serological diagnosis of North American Paragonimiasis by Western blot using Paragonimus kellicotti adult worm antigen

Abstract

Abstract. We studied the value of an IgG Western blot (WB) with Paragonimus kellicotti (Pk) antigen for diagnosis of North American paragonimiasis. The test was evaluated with sera from patients with Pk and Paragonimus westermani infections, with control sera from patients with other helminth infections, and sera from healthy Americans. All 11 proven Pk infection sera and two samples from suspected cases that were negative by P. westermani WB at the Centers for Disease Control and Prevention (CDC) contained antibodies to antigens at 34 kDa and at 21/23 kDa. Seven of 7 P. westermani sera contained antibodies to the 34 kDa antigen, but only 2 recognized the 21/23 kDa doublet. No control samples were reactive with these antigens. Antibody reactivity declined after praziquantel treatment. Thus, the P. kellicotti WB appears to be superior to P. westermani WB for diagnosing Pk infections, and it may be useful for assessing responses to treatment.

Figure 1.

Total IgG Western blot using soluble Paragonimus kellicotti adult worm antigen tested with sera from individuals with or without proven Paragonimus infection. Lane 1, positive control serum from a patient from St. Joseph, Missouri with proven P. kellicotti infection; lane 2, negative control serum from a healthy American without exposure to Paragonimus; lanes 3–7, sera from patients from the Philippines with proven Paragonimus westermani infection; lanes 8 and 9, sera from patients with proven P. kellicotti infection from Missouri; lanes 10 and 11, sera from patients with Echinococcus granulosus infection; lanes 12 and 13, sera from patients with schistosomiasis.

Figure 2.

Western blot using Paragonimus kellicotti adult worm excretory/secretory antigen (lane 1) or soluble total worm antigen (lane 2) using a serum specimen from a patient infected with P. kellicotti.

Figure 3.

Western blot detection of antibodies to soluble Paragonimus kellicotti adult worm antigen in sera from P. kellicotti patients before or after treatment with praziquantel. Lanes 1, 3, 5, and 7, sera from four patients with proven P. kellicotti infections before treatment; lane 2, serum from the same patient as in lane 1 collected 5 weeks after treatment with praziquantel; lane 4, serum from the same patient as in lane 3 collected 8 weeks after treatment with praziquantel; lane 6, serum from the same patient as in lane 5 collected 9 weeks after treatment with praziquantel; lane 8, serum from the same patient as in lane 7 collected 7 weeks after treatment with praziquantel.

Figure 4.

A silver stained SDS page gel shows the major proteins in Paragonimus kellicotti soluble adult worm antigen (lanes 2–4) and in Paragonimus westermani antigen (lanes 5–7). Lane 1, molecular weight markers; lanes 2 and 7, 250 ng protein per lane; lanes 3 and 6, 500 ng protein per lane; lanes 4 and 5, 1 μg protein per lane.

Figure 5.

Comparison of Paragonimus kellicotti (lanes 1–7) and Paragonimus westermani antigen (lanes 8–14) for detecting antibodies to Paragonimus antigens by Western blot. Lanes 1 and 8 tested serum from a suspected P. kellicotti patient (later considered to have not been infected) who did not have antibodies to either antigen; lanes 2 and 9 and 5 and 12 were tested with sera from two proven P. kellicotti patients; lanes 3 and 10 and lanes 4 and 11 tested sera from two proven P. westermani patients; lanes 6 and 13 and lanes 7 and 14 tested sera from two healthy Americans without exposure to Paragonimus.