THE HUMAN ENDOGENOUS RETROVIRUS W GAG PROTEIN

Sarven Sabunciyan¹, Inna Ruslanova¹, Serge Weis²,

1Department

Previously our laboratory

reported Human Endogenous Retro Virus-W (HERV-W) transcripts to be present in

CSF samples obtained from schizophrenia patients and HERV-W transcripts to be

overexpressed in schizophrenic brain tissue.  In order to further examine the

possible involvement of HERV-W in schizophrenia, we developed an assay that

allows us to detect the presence of antibodies against the HERV-W gag protein. 

The longest open reading frame for the HERV-W gag gene in the human genome,

which is present on chromosome 3, was cloned into a baculovirus DNA construct. 

The HERV-W gag protein was then expressed in insect cells and purified using the

attached histidine tag.  This purified protein was used as the antigen in the

Sera from a case control

study containing untreated first episode schizophrenia patients and matched

controls were screened for the presence of antibodies against the HERV-W gag

protein.  Sixteen out of the two hundred twenty screened samples resulted in

positive signals in the ELISA assays.  All sixteen positive sera are from

individuals with recent onset schizophrenia.  Currently we are verifying these

results by western blot analysis and we are also screening more serum samples in

order to determine the extent of the correlation between schizophrenia and

HERV-W.  In addition to linking HERV-W sera Positivity with schizophrenia, these

findings raise some interesting questions regarding the expression of endogenous

retrovirus proteins in the human body.  Why doesn’t everyone have antibodies

against the HERV-W gag protein?  Are proteins from endogenous retroviruses

regarded as self by the immune system or are they expressed only in a small

subset of the population?  Further work in our laboratory will also attempt to