The Journal of Medical Microbiology, Vol 48, Issue 12 1095-1102, Copyright © 1999 by Society for General Microbiology
Acute susceptibility of aged mice to infection with Candida albicans
R. B. Ashman, J. M. Papadimitriou and A. Fulurija
School of Dentistry, University of Queensland, Brisbane, Australia. r.ashman@mailbox.uq.edu.au
The effect of aging on host resistance to systemic candidosis was assessed
by monitoring the course of infection in 16-month-old CBA/CaH mice (aged
non-immune) and in a comparable group that had been infected with a
sublethal dose of Candida albicans at 6 weeks of age (aged immune). Aged
non-immune mice showed rapid progression of the disease, with a marked
increase in the number of mycelia in the brain and kidney, and early
morbidity. Foci of myocardial necrosis were evident, but inflammatory cells
were sparse. The histological picture in the aged immune mice was similar
to that in the aged non-immune group, although fewer mycelial aggregates
were seen. Both groups of aged mice showed a significantly lower fungal
burden in the brain on day 1 of infection, but on day 4, colony counts
increased significantly in the aged non-immune mice. Comparison of cytokine
gene expression in the infected brains showed that the relative amount of
interferon-gamma and tumour necrosis factor-alpha cDNA were similar in all
three groups. Interleukin-6 was elevated in both infected non-immune and
uninfected aged mice. Aged immune mice showed no morbidity after challenge,
and both colonisation and tissue damage were reduced in comparison with the
aged non-immune animals.
