Presently, 21 serotypes have been identified and have no obvious cross-protection among serotypes.But these 21 serotypes have a conservative region in the Ompa and have immunity nature.是什么意思_Presently, 21 serotypes have been identified and have no obvious cross-protection among serotypes.But these 21 serotypes have a conservative region in the Ompa and have immunity nature.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句