International Immunology, Vol. 14, No. 2, 111-119,
February 2002
© 2002 Japanese Society for Immunology
A quantitative model for neutrophil response and delayed-type hypersensitivity reaction in rats orally inoculated with various doses of Salmonella Enteritidis
Microbiological Laboratory for Health Protection, and
1 Laboratory for Pathology and Immunobiology, National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, The Netherlands
Correspondence to: K. Takumi; E-mail: katsuhisa.Takumi{at}rivm.nl
Our aim was to investigate the quantitative relationship between inoculation doses and physiological responses to infection by Salmonella enterica serovar Enteritidis. Rats were orally inoculated with 10–109 c.f.u. of S. Enteritidis and monitored for 6 days. Neutrophil and delayed-type hypersensitivity (DTH) responses were assessed, and the spleens were analyzed for the pathogen. The experimental data were analyzed by a mathematical model for the host response to salmonella infection, which is based on the assumptions that: (i) the number of pathogens in the inoculum is Poisson distributed, (ii) any cell that is inoculated can multiply and form a clone to infect the animal, (iii) the probability of infection by any cell of the pathogen is independent of the number of cells ingested, and (iv) the magnitude of the immune response increases with dose, but eventually saturates to a maximum level. The probability of infection assessed by the DTH response is 7.5 x 10–3/c.f.u. of the inoculum (confidence interval 5.1 x 10–5, 1.2 x 10–2). When five S. Enteritidis independently initiated the infection, the DTH response to the resulting clones of the salmonellae saturated to the maximum level. The probability of infection assessed by the neutrophil response is 3.4 x 10–4/c.f.u. (1.0 x 10–4, 6.8 x 10–4). The response saturated when six S. Enteritidis independently initiated the infection. The probability of infection assessed by the analysis of spleens is 1.2 x 10–3/c.f.u. (4.1 x 10–4, 2.6 x 10–3). We conclude that at low inocula, infections are initiated by very small numbers of bacteria. The magnitude of the immune responses is similar whether only a few or a larger number of bacteria initiated the infection.
Keywords: bacteria, dose, response, infectious immunity, in vivo animal models, mathematical model
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  V. Konjufca, S.-Y. Wanda, M. C. Jenkins, and R. Curtiss III A Recombinant Attenuated Salmonella enterica Serovar Typhimurium Vaccine Encoding Eimeria acervulina Antigen Offers Protection against E. acervulina Challenge Infect. Immun., December 1, 2006; 74(12): 6785 - 6796. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Takumi, J. Garssen, R. de Jonge, W. de Jong, and A. Havelaar Release kinetics and cell trafficking in relation to bacterial growth explain the time course of blood neutrophils and monocytes during primary Salmonella infection Int. Immunol., January 1, 2005; 17(1): 85 - 93. [Abstract] [Full Text] [PDF]
|
|