False-positive labeling of the haustorial cell wall of bean rust: a problem in immunogold labeling of thin sections
- Resource Type
- Authors
- Annerose Heller
- Source
- Micron. 26:15-24
- Subject
- Antiserum
biology
General Physics and Astronomy
Cell Biology
Immunogold labelling
Cell wall
Biochemistry
Structural Biology
Haustorium
Chitinase
biology.protein
General Materials Science
Bovine serum albumin
Antibody
Protein A
- Language
- ISSN
- 0968-4328
False-positive labeling was studied by immunogold-labeling methods. It was observed during an investigation of chitinase distribution in rust-infected bean leaves. Sixteen of the 23 antisera/immunoglobulins tested gave distinct and apparently specific labeling of the haustorial cell wall of the fungus, also with non-immune sera and non-related antisera: all of them were rabbit antisera or immunoglobulins. Only the three monoclonal and four of the rabbit sera (two non-immune and two antisera against plant viruses) showed weak or no reactions. The effect was demonstrated with antiserum against rubisco, which labeled the haustorical cell wall in rather high dilutions. There were no disturbing antibodies against fungi in the sera of the rabbits as suitable acetone powders were inefficient. The type of binding and which component of the cell wall is involved are unknown. It is speculated that there might be a similar binding effect as with protein A to certain mammal immunoglobulins. Blocking with normal goat serum reduced the effect but use of bovine serum albumin (BSA), gelatine and Tween 20 was ineffective. The localization experiment of chitinase is a case in point concerning the misinterpretation of the specificity of an immunogold-labeling test. Therefore, standard controls are by no means sufficient and the specificity has to be confirmed by multiple controls.