Effect of potato physiology on the interpretation of ELISA results for potato leafroll virus

Abstract

This paper records the occurrence of an antigen produced in plants infected by potato leafroll virus (PLRV), which is copurified with the virus and induces an immune response in rabbits used for virus antiserum production. The antigen also appeared to be produced in uninfected but physiologically stressed potato plants. These plants reacted with antisera to PLRV in ELISA tests, thereby giving false positive results. We refer to the compound as virus‐stress antigen (VSA). The importance of this finding, not only to serological testing for PLRV, but also as a possible explanation for some false‐positive reactions that occur with other host‐virus combinations, is discussed. The necessity of having detailed information on plants from which samples are taken for testing is emphasized.

Discrepancies in Serology-Based and Nucleic Acid-Based Detection and Quantitation of Tomato Spotted Wilt Orthotospovirus in Leaf and Root Tissues from Symptomatic and Asymptomatic Peanut Plants

“…Well-recognized causes of inaccurate detection results include non-homogenous virus distribution in plants, interference of plant extracts, failure to detect certain virus serotypes, and cross-reactivity with other closely related viruses [50]. In addition, physiological and biochemical characteristics of the host plant and tissue type chosen for virus detection are important factors that are known to interfere with serological reactions in ELISA [47][48][49]65]. Non-specific antigen-antibody interaction due to the presence of plant proteins could lead to false positives in ELISA [62,66].…”

“…Non-specific antigen-antibody interaction due to the presence of plant proteins could lead to false positives in ELISA [62,66]. Detection of potato leafroll virus (PLRV) in potato tubers via DAS-ELISA resulted in a 70% overestimation of PLRV infection due to false positives [65]. Gunn and Pares (1988) [65] speculated that the false positives could have been caused by non-specific antibodies originating from co-purification of non-virus antigens (i.e., plant proteins) along with PLRV in the PLRV-specific antibody production process.…”

“…Detection of potato leafroll virus (PLRV) in potato tubers via DAS-ELISA resulted in a 70% overestimation of PLRV infection due to false positives [65]. Gunn and Pares (1988) [65] speculated that the false positives could have been caused by non-specific antibodies originating from co-purification of non-virus antigens (i.e., plant proteins) along with PLRV in the PLRV-specific antibody production process. While blocking reagents, such as ovalbumin, bovine serum albumin (BSA), and polyvinylpyrrolidone (PVP) are typically included in the commercial DAS-ELISA kits to reduce non-specific reactions, false positives could still arise from non-virus antigen-antibody interactions.…”

“…While blocking reagents, such as ovalbumin, bovine serum albumin (BSA), and polyvinylpyrrolidone (PVP) are typically included in the commercial DAS-ELISA kits to reduce non-specific reactions, false positives could still arise from non-virus antigen-antibody interactions. Plant proteins such as pathogenesisrelated proteins, lectins, and sesquiterpenoids are often present in virus-infected plants, and these plant-originated proteins could induce non-specific binding in ELISA [65,67,68]. For example, non-specific reactions in DAS-ELISA for cucumber mosaic virus detection in ornamental plants and wild weed species resulted in false positives [48,49].…”