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Infection and Immunity, January 2000, p. 352-359, Vol. 68, No. 1
Departamento de Imunologia, Instituto de
Ciências Biomédicas da Universidade de São Paulo,
São Paulo, Brazil
Received 12 April 1999/Returned for modification 7 May
1999/Accepted 7 October 1999
Using a pulmonary model of infection, we demonstrated previously
that A/Sn and B10.A mice are, respectively, resistant and susceptible
to Paracoccidioides brasiliensis infection. Employing the
same experimental model, we examined herein the role of
CD8+ T cells in the course of paracoccidioidomycosis.
Treatment with anti-CD8 monoclonal antibodies caused a selective
depletion of pulmonary and splenic CD8+ T cells in both
mouse strains. The number of pulmonary CD4+ T cells and
immunoglobulin-positive cells was independent of the number of
CD8+ T cells. In susceptible mice, the loss of
CD8+ T cells by in vivo treatment with anti-CD8 monoclonal
antibodies impaired the clearance of yeasts from the lungs and
increased the fungal dissemination to the liver and spleen. The same
treatment in resistant mice increased fungal dissemination to
extrapulmonary tissues but did not alter the pulmonary fungal load.
Furthermore, CD8+ T-cell depletion did not modify
delayed-type hypersensitivity reactions of A/Sn mice but increased
these reactions in B10.A mice. The production of P. brasiliensis-specific antibodies by resistant and susceptible
mice depleted of CD8+ T cells was similar to that of mice
given control antibody. Histopathologically, depletion of
CD8+ T cells did not disorganize the focal granulomatous
lesions developed by both mouse strains. These results indicate that
CD8+ T cells are necessary for optimal clearance of the
fungus from tissues of mice infected with P. brasiliensis
and demonstrate more prominent protective activity by those cells in
the immune responses mounted by susceptible animals.
0019-9567/0/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Depletion of CD8+ T Cells In Vivo Impairs Host
Defense of Mice Resistant and Susceptible to Pulmonary
Paracoccidioidomycosis

*
Corresponding author. Mailing address: Depto. de
Imunologia, Instituto de Ciências Biomédicas, Universidade
de São Paulo, Av. Prof. Lineu Prestes 1730, Cep 05508-900, São Paulo SP, Brazil. Phone: 55-11-818 7397. Fax: 55-11-818 7224. E-mail: vlcalich{at}icb.usp.br.
Present address: Laboratório de Micologia Experimental,
Corporación para Investigaciones Biológicas (CIB),
Medellín, Colombia.
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