Enzyme-linked immunosorbent assay and serologic responses to Pneumocystis jiroveci

Abstract

Seroepidemiologic studies of Pneumocystis pneumonia (PCP) in humans have been limited by inadequate reagents. We have developed an enzyme-linked immunosorbent assay (ELISA) using three overlapping recombinant fragments of the human Pneumocystis major surface glycoprotein (MsgA, MsgB, and MsgC) for analysis of antibody responses in HIV-positive patients and healthy blood donors. HIV-positive patients had significantly higher antibody levels to all Msg fragments. Furthermore, HIV-positive patients who experienced a previous episode of PCP (PCP-positive) had higher levels of antibodies to MsgC than patients who never had PCP. A significant association was found between ELISA antibody level and reactivity by Western blot in HIV-positive patients, especially those who were PCP-positive. Thus, this ELISA will be useful in studying serum antibody responses to Pneumocystis in different human populations.

Figure

Antibody reactivity of healthy blood donors (donors); HIV-positive; PCP-positive, HIV-positive; and PCP-negative, HIV-positive patients to human Pneumocystis major surface glycoprotein C (MsgC) by enzyme-linked immunosorbent assay 1 (ratio to pET), showing the range, 25% and 75% confidence intervals, and median of the data. Data were log-transformed to approximate normality.