The CD45RA+ (quiescent) cellular phenotype is overabundant relative to the CD45RA- phenotype within the involuted splenic T cell population of weanling mice subjected to wasting protein-energy malnutrition.
The objective of this investigation was to determine whether an imbalance between naive- and memory-phenotype cells occurs within CD4+ and/or CD8+ splenic T cell subsets in models of protein-energy malnutrition (PEM) which produce wasting disease (loss of approximately 1.6% of body weight per day for 14 d) and profound depression in thymus-dependent immunity. Male and female weanling mice of disparate inbred strains, CBA/J and C57BL/6J, were allocated to the following groups: zero-time control (23 d old and 19 d old, respectively), ad libitum intake of a complete purified diet (19% crude protein, 17 kJ/g gross energy), restricted intake of the complete diet, and (C57BL/6J, only) ad libitum intake of an isocaloric low protein diet (0.6% crude protein). Surface expression of isoforms of CD45, a component of the T cell receptor complex, as well as of the accessory molecule, CD2, were assessed by flow cytometry of splenic mononuclear cell suspensions. Both major T cell subsets in the malnourished groups contained a significantly higher proportion of cells expressing the surface marker, CD45RA, than was found in the spleen cells of the control groups. CD45RA+ (naive-phenotype) T cells represent the extreme of quiescence and stringent activation requirements among thymic lymphocytes. The results provide the first clear evidence of a T cell subset imbalance in PEM which is consistent with depression in acquired immunity and which occurs, apart from antigenic challenge, in a site wherein immune responses take place. The T cell receptor complex may emerge as a focal point of the depressive influence of PEM on the competence of thymic lymphocytes.
Woodward
B D
BD
Department of Nutritional Sciences, University of Guelph, Ontario, Canada.
Bezanson
K D
KD
Hillyer
L M
LM
Lee
W H
WH
D000375:Aging / Q000276:immunology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis / Q000276:immunology; D001835:Body Weight / Q000502:physiology; D018801:CD2 Antigens / Q000032:analysis; D004435:Eating / Q000502:physiology; D005260:Female; D005434:Flow Cytometry; D017493:Leukocyte Common Antigens / Q000032:analysis* / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D010641:Phenotype; D011502:Protein-Energy Malnutrition / Q000276:immunology* / Q000473:pathology / Q000503:physiopathology; D013154:Spleen / Q000473:pathology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology*; D013950:Thymus Gland / Q000473:pathology; D014886:Weaning
D000911:Antibodies, Monoclonal; D018801:CD2 Antigens; D017493:Leukocyte Common Antigens