Objective To investigate the dynamics changes of the
myeloid-derived suppressor cells (
MDSCs) and regulatory T (Treg)
cells in
mice infected with
Echinococcus granulosus and explore the possible
biological significance.
Methods Thirty
female BALB/c
mice of 6 weeks old were randomly divided into the
infection and
control groups, of 15
mice in each group.
Mice in the
infection group were intraperitoneally injected with 2 000 E. granulosus protoscoleces, while those in the
control group were injected with the same volume of physiological saline.
Mouse liver white blood cells were harvested 3 (early stage), 6 (medium stage) and 12 months (late stage) post-
infection, and the proportions of
MDSCs, their subpopulations (M-
MDSCs and PMN-
MDSCs) and
Treg cells were assessed by
flow cytometry. Results The proportions of
MDSCs were (1.61 ± 0.36)%, (5.68 ± 0.69)% and (16.18 ± 0.69)% in
mouse liver white blood cells in the
infection group 3, 6 and 12 months post-
infection with E. granulosus, and (2.19 ± 0.42)%, (0.99 ± 0.07) % and (4.18 ± 0.84)% in the
control group, and there were significant differences in the proportion of the
MDSCs in
mouse liver white blood cells between the
infection and
control groups 6 and 12 months post-
infection (P < 0.01). The proportions of M-
MDSCs were (0.69 ± 0.27)%, (5.30 ± 0.72)% and (10.75 ± 0.29)% in
mouse liver white blood cells in the
infection group 3, 6 and 12 months post-
infection, and (0.42 ± 0.24)%, (0.69 ± 0.02)% and (2.12 ± 0.13)% in the
control group, and there were significant differences in the proportion of the M-
MDSCs in the
mouse liver white blood cells between the
infection and
control groups 6 and 12 months post-
infection (P < 0.01). The proportions of PMN-
MDSCs were (0.93 ± 0.23)%, (0.32 ± 0.02)% and (5.14 ± 1.03)% in
mouse liver white blood cells in the
infection group 3, 6 and 12 months post-
infection, and (1.77 ± 0.26)%, (0.28 ± 0.05)% and (1.99 ± 0.90)% in the
control group, and there were significant differences in the proportion of PMN-
MDSCs in
mouse liver white blood cells between the
infection and
control groups 3 and 12 months post-
infection (P < 0.05). The proportions of
Treg cells were (3.35 ± 0.14)%, (6.24 ± 0.38)% and (3.41 ± 0.07)% in
mouse liver white blood cells in the
infection group 3, 6 and 12 months post-
infection, and (3.48 ± 0.46)%, (3.65 ± 0.45)% and (3.12 ± 0.12)% in the
control group, and there were significant differences in the proportion of
Treg cells in
mouse liver white blood cells between the
infection and
control groups 6 and 12 months post-
infection (P < 0.01). Conclusions The percentages of both
MDSCs and
Treg cells increase in
mouse liver white blood cells 6 and 12 months post-
infection with E. granulosus, and a more remarkable increase is seen in the percentage of
MDSCs, which is mainly found in M-
MDSCs. These findings suggest that M-
MDSCs may
play a major immunosuppressive
role in the medium and late stages of E. granulosus
infection in
mice.