Detection of individual microbial pathogens by proximity ligation.
BACKGROUND
Nucleic acid amplification allows the detection of single infectious agents. Protein-based assays, although they provide information on ongoing infections, have substantially less detection sensitivity.


METHODS
We used proximity ligation reactions to detect proteins on bacteria and virus particles via nucleic acid amplification. Antibodies recognizing viral or bacterial surface proteins were equipped with DNA strands that could be joined by ligation when several antibodies were bound in proximity to surface proteins of individual infectious agents.


RESULTS
Detection sensitivities similar to those of nucleic acid-based detection reactions were achieved directly in infected samples for a parvovirus and an intracellular bacterium.


CONCLUSIONS
This method enables detection of ligated DNA strands with good sensitivity by real-time PCR and could be of value for early diagnosis of infectious disease and in biodefense.
Gustafsdottir
Sigrun M
SM
The Beijer Laboratory, Department of Genetics and Pathology, Rudbeck Laboratory, Uppsala, Sweden.
Nordengrahn
Ann
A
Fredriksson
Simon
S
Wallgren
Per
P
Rivera
Esteban
E
Schallmeiner
Edith
E
Merza
Malik
M
Landegren
Ulf
U
D000818:Animals; D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins / Q000032:analysis / Q000235:genetics; D001431:Bacteriological Techniques; D019921:Biotinylation; D004797:Enzyme-Linked Immunosorbent Assay; D005243:Feces / Q000382:microbiology; D005260:Female; D005333:Fetus / Q000821:virology; D020639:Lawsonia Bacteria / Q000145:classification* / Q000235:genetics / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D021141:Nucleic Acid Amplification Techniques; D010322:Parvoviridae Infections / Q000662:veterinary / Q000821:virology; D028323:Parvovirus, Porcine / Q000145:classification* / Q000235:genetics / Q000276:immunology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000662:veterinary / Q000821:virology; D012680:Sensitivity and Specificity; D013552:Swine; D013553:Swine Diseases / Q000821:virology; D014764:Viral Proteins / Q000032:analysis / Q000235:genetics; D014771:Virion / Q000145:classification / Q000235:genetics; D014773:Virology / Q000379:methods
D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D014764:Viral Proteins