Page 422 - Veterinary Immunology, 10th Edition

VetBooks.ir Species Differences

The details of helper T cell subpopulations described above have
largely been derived from studies in laboratory mice and humans.

Cattle most certainly possess Th1 and Th2 cells and can mount
polarized immune responses. Bovine IgG1 expression is positively
regulated by IL-4 and IgG2 expression by IFN-γ. Many bovine CD4 +
cells produce IL-2, IL-4, IL-10, and IFN-γ.

γ/δ T Cells

The proportion of T cells with γ/δ TCRs differ greatly between
mammals. In some species, such as humans and mice, fewer than
5% have γ/δ TCRs (γ/δ-low). In others, such as pigs and ruminants,

up to 66% of T cells in young calves and 85% in piglets express γ/δ
TCRs (γ/δ-high). This decreases with age but still remains relatively
high in adults (8%-18% in adult cattle). These cells have different
functions in these two groups of mammals (Fig. 14.21).

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