Page 1309 - Veterinary Immunology, 10th Edition

normal antibody response to tetanus toxoid but respond poorly to
VetBooks.ir dinitrochlorobenzene or tuberculin, both of which induce cell-

mediated reactions. If these calves are treated by oral zinc oxide or
zinc sulfate, they recover the ability to mount normal cell-mediated

responses. If, however, the zinc supplementation is stopped, the
animals will relapse within a few weeks. It is probable that these
animals have a reduced ability to absorb zinc from the intestine.
Zinc is an essential component of the thymic hormone thymulin

(Chapter 12) and is therefore required for a normal T cell response.

Other Immunodeficiencies

A transient hypogammaglobulinemia associated with a delayed
onset of immunoglobulin synthesis has been recorded in a

Simmental heifer, and a case of thymic aplasia with absence of hair
has been described in calves. It resembles the “nude” mutation seen
in mice and cats (discussed later).

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