Exploratory reference intervals on hematology and cellular immune system of multiparous Large White sows

Abstract

There is significant lack of basic hematologic and immunological data in adult sows. Therefore, aim of this study was to provide respective reference intervals. 32 clinically healthy multiparous Large White sows aged 33.5 ± 9.6 months and all of them two months postpartum were included in this study. Mean erythrocyte count was 5.5 ± 0.7 × 10(6)/μl and total leukocyte count was 12.1 ± 2.1 × 10(3)/μl. Proportion of lymphocytes was 44.7 ± 10.2% and of neutrophils 41.6 ± 11.0%. The ratio of naïve T helper (Th) cells to memory Th cells was 1:3.1 and the ratio of Th cells to cytotoxic T cells (CTLs) was 1:4.2. Proportions of regulatory T cells, NK cells, and CD21(+) B cells were lower (3.1, 2.6, and 6.0%) than those of memory Th cells ranging from 8.8 to 27.5% depending on the activation status and CTLs with 37.3%. γδ T cells were found at comparably high numbers (19.1%). Flow cytometric measurement of intracellular cytokines in PBMCs revealed marginal levels for IL-1β, IL-2, IL-4, IL-6, IL-10, and IL-12p35, but remarkable levels for TNF-α and IFN-γ. Highest mRNA levels were found for IL-1, IL-10, and TNF-α, with TNF-α showing the least inter-individual variation.

Fig. 1

Contour plots of analysed leukocyte populations and lymphocyte subpopulations. (a) Main PBMC populations in the forward vs. side scatter. (b) Monocytes and pDCs as characterized by their expression of the porcine pan-myeloid marker SWC3 as well as CD4. (c) CD21⁺ B cells. (d) Typical CD4 and CD8 expression pattern of porcine lymphocytes with a significant proportion of extrathymic CD4⁺CD8⁺ double positive cells. (e) Activated Th cells. (f) Memory Th cells. (g) NK cells and CTLs. (h) Tregs. (i) γδ T cells.