The CD4/CD8 ratio in the blood does not reflect the response of this index in secondary lymphoid organs of weanling mice in models of protein-energy malnutrition known to depress thymus-dependent immunity.
A low ratio of cellular numbers within CD4+ (helper/inducer) relative to CD8+ (suppressor/cytotoxic) thymic lymphocyte subsets (low CD4/CD8 ratio) is widely accepted as fundamental to the depression in thymus-dependent immunocompetence associated with wasting protein-energy malnutrition (PEM). The objective of this investigation, therefore was to determine the CD4/CD8 ratio in peripheral lymphoid compartments of diverse murine models of protein-energy malnutrition which produce systemic wasting (loss of approximately 1.8% of initial body weight per day), lymphoid involution and (as shown in many previous studies) depression in thymus-dependent immunocompetence. In the first of two experiments, male and female weanling mice of disparate inbred strains, CBA/J and C57BL/6J, were allocated to a zero-time control group (23- and 19-d-old, respectively), or to groups fed for 14 d as follows: ad libitum intake of a complete purified diet (19% crude protein, 17 kJ/g gross energy), restricted intake of the complete diet, or ad libitum intake of an isocaloric low protein diet (0.6% crude protein). In a supplementary experiment, (0.6% crude protein). In a supplementary experiment, male and female C57BL/6J weanling mice were fed the complete diet or the low protein diet for either 6 or 21 d. CD4+ and CD8+ thymic lymphocytes were enumerated by flow cytometry in mononuclear cell suspensions from blood, spleen and mesenteric lymph nodes. A low CD4/CD8 ratio is common in the blood in wasting protein-energy malnutrition, but appears uncharacteristic of the profoundly involuted lymphoid organs which generate acquired immune responses. The CD4/CD8 ratio is irrelevant to the thymus-dependent immunoincompetence previously demonstrated in the rodent models used in this investigation.
Lee
W H
WH
Department of Human Biology and Nutritional Sciences, University of Guelph, Ontario, Canada.
Woodward
B D
BD
D000818:Animals; D016516:CD4-CD8 Ratio; D004195:Disease Models, Animal; D005260:Female; D008198:Lymph Nodes / Q000166:cytology / Q000276:immunology; D008221:Lymphoid Tissue / Q000166:cytology / Q000276:immunology*; D008297:Male; D008643:Mesentery; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D011502:Protein-Energy Malnutrition / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013950:Thymus Gland / Q000276:immunology*; D014886:Weaning