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 language | English (US) |
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Pages (from-to) | 1293-1305 |
Number of pages | 13 |
Journal | Nutrition Research |
Volume | 6 |
Issue number | 11 |
DOIs | |
State | Published - Nov 1986 |
Externally published | Yes |
Keywords
- Dietary protein
- immune response
- suppressor cells
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Endocrinology
- Nutrition and Dietetics