RESISTANCE TO INFECTION WITH LISTERIA-MONOCYTOGENES IN NORMAL AND THYMUS-LESS MICE TREATED WITH AMPICILLIN

  • 1 January 1978
    • journal article
    • research article
    • Vol. 240  (3) , 339-346
Abstract
NMRI mice infected i.v. with a sublethal dose of L. monocytogenes were divided into 4 groups. One group served as the control and the other 3 were treated with ampicillin beginning 4,8 or 24 h after infection. The animals were injected in the morning and in the evening each time with 4 mg ampicillin s.c. until a total dose of 48 mg was reached. As demonstrated by counting of the bacteria in the spleen, Listeria multiplied in the ampicillin treated mice in comparison to the control group. Ampicillin delayed the infection but it continued to persist for some days at a level of 103 - 104 Listeria per spleen irregardless of the treatment regimen. Eight days after the 1st infection all animals received a challenge dose of 104 Listeria. Compared with the control animals the ampicillin treated mich had a reduced immunity, even in the group in which ampicillin application was started 24 h after the primary infection. If the challenge infection was given after an interval of 6 wk between primary and secondary infection, only a reduced immunity was found. Furthermore, spleen cells of mice 7 after infection were able to transfer immunity to untreated recipients: spleen cells of ampicillin treated mice were unable to do so. Finally, an attempt was made to cure chronic listeric infection in nude mice by the application of high doses of ampicillin. T[thymus-derived]-cells probably play a primary role in the elimination of the bacteria.