competition were prepared and compared as shown in fig2 for the results the competition of app sp decreased the signal intensity by 92 thus the monoclonal antibody could be confirmed to have the property of binding to app sp when the subclass of the monoclonal antibody produced by 12a3 hybridoma was analyzed using a mouse monoclonal antibody subclass determination kit from roche it was shown to be igg2a pristane from sigma was intraperitoneally administered in a volume of 0 5 ml per mouse to 3 female balb c mice after 1 week 1 u00d7 10 7 cells per mouse of 12a3 hybridoma cultured in advance was intraperitoneally administered after 1 week ascites fluid was collected and centrifuged to recover the supernatant from the 3 mice 9 5 ml of the supernatant was obtained a saturated ammonium sulfate solution was added dropwise to 50 to the resultant supernatant which was then stirred at 4 u00b0 c for 1 hour then centrifugation operation was carried out and the supernatant was discarded again 50 saturated ammonium sulfate and pbs ph 7 4 were added and the resultant was slightly stirred and then centrifuged followed by discarding the supernatant pbs ph 7 4 was added to the resultant precipitate for resolution in addition buffer exchange to phosphate buffer was performed using a desalting column pd 10 from ge healthcare from the solution only an igg fraction was purified by affinity.