Human LINE1 endonuclease domain as a putative target of SARS-associated autoantibodies involved in the pathogenesis of severe acute respiratory syndrome.
BACKGROUND
Severe acute respiratory syndrome (SARS) is a disease with a mortality of 9.56%. Although SARS is etiologically linked to a new coronavirus (SARS-CoV) and functional cell receptor has been identified, the pathogenesis of the virus infection is largely unclear.


METHODS
The clinical specimens were processed and analyzed using an indirect enzyme-linked immunosorbent assay (ELISA) in-house. Further investigations of target antigen included reviews of phage display technique, rapid amplification of cDNA ends (RACE) technique, protein expression and purification, Western blotting validation, serological and immunohistochemical staining in postmortem tissue.


RESULTS
A type of medium or low titer anti-lung tissue antibodies were found in the sera of SARS patients at the early stage of the disease. Human long interspersed nuclear element 1 (LINE1) gene endonuclease (EN) domain protein was one of the target autoantigens and it was aberrantly expressed in the lung tissue of SARS patients. Anti-EN antibody was positive in the sera of 40.9% of SARS patients.


CONCLUSIONS
Human LINE1 endonuclease domain was identified as a putative target of SARS-associated autoantibodies, which were presented in the serum of SARS patients and may be involved in the pathogenesis of SARS.
He
Wei-ping
WP
Department of Immunology and Infectious Diseases, Beijing No 302 Hospital, Beijing 100039, China.
Shu
Cui-li
CL
Li
Bo-an
BA
Zhao
Jun
J
Cheng
Yun
Y
D000914:Antibodies, Viral / Q000276:immunology*; D001323:Autoantibodies / Q000276:immunology*; D004720:Endonucleases / Q000276:immunology*; D015723:Gene Library; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000276:immunology*; D016133:Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000276:immunology*; D045169:Severe Acute Respiratory Syndrome / Q000209:etiology*
D000914:Antibodies, Viral; D001323:Autoantibodies; D004720:Endonucleases