Watson D L, Gill H S
Division of Animal Health, CSIRO, Armidale, New South Wales, Australia.
Res Vet Sci. 1991 Jul;51(1):88-93. doi: 10.1016/0034-5288(91)90037-o.
Sheep in five age groups (two weeks, 10 weeks, 18 weeks, six months and four years old) were immunised systemically, twice, with ovalbumin or Brucella abortus (live or killed) and antibody responses in blood were measured. The animals were also infected with the nematode parasites Trichostrongylus colubriformis and Haemonchus contortus and faecal egg counts and serum antibody responses to larval antigens were measured. The experiments were designed so that, as far as possible, the effect of age per se could be dissociated from the combined effects of age and prior exposure to antigen. The effects of the age of sheep were more marked for antibody responses to Brucella abortus lipopolysaccharide than to ovalbumin. Older animals had much greater resistance to infection with internal parasites, as shown by the magnitude of the faecal egg count. In contrast to older lambs, neonatal lambs (infected with H contortus at two weeks old) had consistently declining concentrations of anti-H contortus antibody in their serum, mounted no detectable autogenous anti-H contortus antibody response in blood and appeared to develop no resistance to the parasite. Post natal ontogeny of immune responses was different for the various antigens/pathogens.
将五个年龄组（两周、十周、十八周、六个月和四岁）的绵羊用卵清蛋白或流产布鲁氏菌（活菌或死菌）进行两次全身免疫，并检测血液中的抗体反应。这些动物还感染了线虫寄生虫——蛇形毛圆线虫和捻转血矛线虫，并检测粪便虫卵计数以及血清对幼虫抗原的抗体反应。实验设计的目的是尽可能将年龄本身的影响与年龄和先前接触抗原的综合影响区分开来。绵羊年龄对流产布鲁氏菌脂多糖抗体反应的影响比对卵清蛋白的影响更明显。粪便虫卵计数表明，年龄较大的动物对体内寄生虫感染的抵抗力更强。与较大的羔羊相比，新生羔羊（两周龄时感染捻转血矛线虫）血清中抗捻转血矛线虫抗体浓度持续下降，血液中未检测到自身抗捻转血矛线虫抗体反应，似乎对该寄生虫没有产生抵抗力。不同抗原/病原体的免疫反应出生后个体发育情况各不相同。
