Restoration of immunoregulation in splenic lymphocyte populations of mice fed reduced dietary protein

Thomas M. Petro, Bennett G. Smith, Richard Raybourne

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Moderate, acute reduction of dietary protein in young mice often leads to increases in humoral immune responses. To test the hypothesis that reduction of dietary protein affects T lymphocyte regulation of the humoral immune response, in vitro humoral immune responses to sheep erythrocytes (SRBC) and bromelain-treated mouse erythrocytes (BrMRBC), were examined in BDF1 and BALB/c mice fed diets low in protein (4% or 6% casein) compared with well-fed (20% casein) controls. In addition, the immunoregulatory splenic T lymphocyte subset profile was evaluated in mice fed the 4% and 20% casein diets. Groups of female BDF1 and BALB/c mice 5 weeks of age were fed one of the three diets for 5 weeks. Mice fed the 4% casein diet exhibited less body weight and splenic lymphocyte number than mice from the other two dietary groups. BDF1 but not BALB/c mice fed the 4% casein diet exhibited significantly increased in vitro and in vivo immune responses to optimal or high doses of SRBC. On the other hand, both BDF1 and BALB/c mice fed the 4% casein diet exhibited a significantly higher immune response to BrMRBC. The increased response of 4% casein-fed BDF1 mice was related to an inability to generate adequate specific immunoregulatory T cells involved in suppressing the response. Co-culturing with Lyt1+ or Lyt2+ T cells from well-fed mice regulated downwardly the enhanced autoimmune, anti-BrMRBC response of mice fed the 4% casein diet. Decreased suppressor T lymphocyte activity in BDF1 mice, but not BALB/c mice fed the 4% casein diet was confirmed by the significant depression of the Lyt2+ suppressor T cell number in the spleen evaluated by direct immunofluorescence using monoclonal antibodies which identify T lymphocyte subsets. These results indicate that moderate, acute reduction of dietary protein in young mice affects the regulatory functions of T cells but not the differentiation of B cells to antibody-forming plasma cells. This effect seems to be dependent upon the strain of mouse used.

Original languageEnglish (US)
Pages (from-to)1293-1305
Number of pages13
JournalNutrition Research
Volume6
Issue number11
DOIs
StatePublished - Nov 1986

Keywords

  • Dietary protein
  • immune response
  • suppressor cells

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Nutrition and Dietetics

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