passive immunity to infection with t. pallidum , however , seems to be dose related , since asymptomatic infection persisted for as long as 3 months after challenge in strain 2 guinea pigs transfused with 10 ( 8 ) t. pallidum-immune lymphocytes , but not in c4d recipients of twice as many immune cells .
C0009450
infection
C0275522
asymptomatic infection