Effects of Vitamin B6 Deficiency on the Composition and Functional Potential of T Cell Populations

Abstract

The immune system is critical in preventing infection and cancer, and malnutrition can weaken different aspects of the immune system to undermine immunity. Previous studies suggested that vitamin B6 deficiency could decrease serum antibody production with concomitant increase in IL4 expression. However, evidence on whether vitamin B6 deficiency would impair immune cell differentiation, cytokines secretion, and signal molecule expression involved in JAK/STAT signaling pathway to regulate immune response remains largely unknown. The aim of this study is to investigate the effects of vitamin B6 deficiency on the immune system through analysis of T lymphocyte differentiation, IL-2, IL-4, and INF-γ secretion, and SOCS-1 and T-bet gene transcription. We generated a vitamin B6-deficient mouse model via vitamin B6-depletion diet. The results showed that vitamin B6 deficiency retards growth, inhibits lymphocyte proliferation, and interferes with its differentiation. After ConA stimulation, vitamin B6 deficiency led to decrease in IL-2 and increase in IL-4 but had no influence on IFN-γ. Real-time PCR analysis showed that vitamin B6 deficiency downregulated T-bet and upregulated SOCS-1 transcription. This study suggested that vitamin B6 deficiency influenced the immunity in organisms. Meanwhile, the appropriate supplement of vitamin B6 could benefit immunity of the organism.

Figure 1

Body weight and body weight gain rate of BLAB/c mice fed with the experiment diets. Growth rate was calculated using the formula: Growth  rate = (Body weight_{n week} − Body weight_0  week)/Body weight_{0 week}. Each column represents the mean ± SEM (n = 7) with three independent experiments. Mean values with asterisk (∗) attached indicate significant difference (P < 0.05) among the groups at the same time point.

Figure 2

Capacity of lymphocyte proliferation. The stimulation index (SI) was calculated using the following formula “proliferation of T lymphocytes incubated with ConA stimulation divided by proliferation of T lymphocytes incubated without ConA stimulation.” Each column data represents mean values of seven replications with three independent experiments. SI index with ∗ denotes significant differences among the groups (P < 0.05).

Figure 3

Level of T lymphocyte cell with or without ConA stimulation ((a), (b), and (c)) and differentiation of CD4+ and CD8+ subsets with or without ConA stimulation (d). Calculation was based on the percentage of concentration. Each group data represents mean values of seven replications with three independent experiments. Column marked with different alphabets denotes significant differences among the groups (P < 0.05).

Figure 4

Cytokines IL-2 (a), IL-4 (b), and IFN-γ (c) secretion level of different vitamin B6 diet mice splenocytes after ConA stimulation. 5 μg/mL ConA was added to stimulate the splenocyte, while the control received the same volume of RMPI1640 medium. After 48 h of incubation, cytokine levels in the culture medium were measured by ELISA method. Each column represents the mean ± SD of seven replications with three independent experiments. Columns marked with different letters are significantly different (P < 0.05) among different diet mouse.

Figure 5

Real-time RNA results. mRNA SOCS-1 (a), T-bet (b) expression level of different vitamin B6 diet mice splenocytes after ConA stimulation. 5 μg/mL ConA was added to stimulate the splenocyte, while the control received the same volume of RMPI1640 medium. After 24 h of incubation, mRNA was extracted and reversed. Each column represents the mean ± SD (n = 7) with three independent experiments. Columns marked with different letters are significantly different (P < 0.05) among different diet mouse.