Page 760 - Veterinary Immunology, 10th Edition
P. 760
VetBooks.ir Development of Adaptive Immunity in
Neonatal Mammals
Local Immunity
The intestinal lymphoid tissues of neonatal mammals respond
rapidly to ingested antigens. For example, calves vaccinated orally
with coronavirus vaccines at birth are resistant to virulent
coronavirus within 3 to 9 days. Likewise, piglets vaccinated orally 3
days after birth with transmissible gastroenteritis virus vaccines
develop neutralizing antibodies in the intestine 5 to 14 days later.
Much of this early resistance is attributable to innate production of
IFN-α/β, but there is an early intestinal IgM response that switches
to IgA by 2 weeks. In the young animal, the IgA response appears
earlier and reaches adult levels well before the other
immunoglobulins.
Systemic Immunity
The antibodies acquired by a young animal as a result of ingesting
its mother's colostrum inhibit the ability of the newborn to mount
its own immune response (Fig. 23.10). As a result, very young
animals are unable to respond to active immunization. This
inhibition is B cell specific, and T cell responses are largely
unaffected.
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