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Infect Immun, March 1998, p. 927-931, Vol. 66, No. 3
Department of Medical Microbiology and
Immunology, College of Medicine, Texas A&M University Health
Science Center, College Station, Texas 77843-1114
Received 15 September 1997/Returned for modification 27 October
1997/Accepted 23 December 1997
Previous research has suggested that dietary protein deficiency
alters resistance to experimental pulmonary tuberculosis, in part, by
affecting the distribution and trafficking of antigen-reactive T cells.
In this study, guinea pigs were maintained on either a
protein-deficient (10% ovalbumin) or control (30% ovalbumin) diet and
infected 4 to 6 weeks later with a low dose of virulent Mycobacterium tuberculosis H37Rv by the respiratory route.
Monoclonal antibodies directed against the CD4 or CD8 markers on guinea
pig lymphocytes were used in a flow cytofluorometric assay to determine the proportion of each subset in the peripheral circulation, spleen, and bronchotracheal lymph nodes at 4 weeks after infection. In uninfected guinea pigs, only the spleen exhibited an effect of diet on
T-cell distribution, with small but consistent reductions in the
proportions of both CD4 and CD8 T lymphocytes. However, following
infection, protein deficiency exerted a profound effect on T-cell
distribution. Malnourished, tuberculous guinea pigs harbored only 20 and 60% of the T cells (as a proportion of
total lymphoid cells) found in the spleen and blood, respectively, of their well-nourished counterparts. Normal relative proportions of CD4
and CD8 cells were observed, however. In striking contrast, the
bronchotracheal lymph nodes of protein-deprived guinea pigs with
tuberculosis contained more than twice the numbers of T cells of
control guinea pigs, and the normal CD4-to-CD8 ratio was reversed. Peripheral T-cell function, as measured by the delayed hypersensitivity skin test to tuberculin, and antigen-induced lymphoproliferation in
vitro were markedly suppressed in protein-malnourished animals. Conversely, purified protein derivative-induced (but not concanavalin A-induced) proliferation was significantly enhanced in cultures of
lymph node cells from protein-deprived tuberculous animals. Taken
together, these results suggest that immunological abnormalities and
loss of antimycobacterial resistance in the lungs of protein-deficient guinea pigs may be explained, in part, by sequestration of
antigen-reactive T cells in the lymph nodes draining the site of
infection.
0019-9567/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Protein Deficiency Induces Alterations in the
Distribution of T-Cell Subsets in Experimental Pulmonary
Tuberculosis
and
*
Corresponding author. Mailing address: Department of
Medical Microbiology and Immunology, Reynolds Medical
Building, Room 463, College of Medicine, Texas A&M University
Health Science Center, College Station, TX 77843-1114. Phone: (409)
845-1367. Fax: (409) 845-3479. E-mail: dmcmurray{at}tamu.edu.
Present address: Department of Pediatrics, George Washington
University School of Medicine, Washington, D.C.
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