CENID-Parasitología Veterinaria, INIFAP, Jiutepec, Mexico.
Transbound Emerg Dis. 2010 Apr;57(1-2):87-90. doi: 10.1111/j.1865-1682.2010.01117.x.
The purpose of this research was to evaluate the recombinant proteins MSA-1, MSA-2c and 12D3 as a combined immunogen for cattle. Fifteen steers were randomly assigned into three groups of five animals each (I, II and III). On day 0, cattle in group I were injected with 50 microg each of rMSA-1, rMSA-2c and r12D3 with the adjuvant Montanide 75; cattle in Group II received adjuvant-PBS, and Group III were untreated controls. On day 14, cattle in Group I received a second injection of the three recombinant proteins in adjuvant and cattle in Group II again received adjuvant alone. On day 28, all groups of cattle were challenged with a field strain of Babesia bovis. After challenge, the experimental cattle were clinically and serologically monitored. Three of the five steers immunized with the combined recombinant B. bovis proteins seroconverted on day 14 post-immunization (P.I.) and the maximum titre was 1 : 1600. All five immunized steers presented strong seropositivity to B. bovis antigens at day 21 P.I. The prepatent periods of vaccinated cattle were delayed until day 10 post-challenge exposure versus 8 and 7 days in Groups II and III, respectively. Cattle in all groups had fever above 41 degrees C; the reduction in packed cell volume was not significantly different (P > 0.05) in vaccinated group I compared with Groups II and III (29% versus 26% and 31%, respectively). Treatment was required for one steer in the control group. During the period of the study, the weight of cattle in Groups I and II increased an average of 9 and 7 kg, whereas the weight of the control cattle was reduced on average 4 kg. Immunization with rMSA-1-rMSA-2c-r12D3 proteins was not sufficient to prevent clinical symptoms against challenge, but the immunologic response was sufficient to protect steers against a mild virulent strain of B. bovis.
这项研究的目的是评估重组蛋白 MSA-1、MSA-2c 和 12D3 作为牛的联合免疫原。15 头公牛被随机分为三组，每组 5 头（I、II 和 III 组）。在第 0 天，I 组牛分别注射 50μg 重组蛋白 rMSA-1、rMSA-2c 和 r12D3 佐剂 Montanide 75；II 组牛注射佐剂-PBS，III 组牛未处理。在第 14 天，I 组牛再次接受三种重组蛋白的佐剂注射，II 组牛再次接受佐剂注射。在第 28 天，所有组的牛都接受了田间株 Babesia bovis 的挑战。挑战后，对实验牛进行临床和血清学监测。用联合重组 B. bovis 蛋白免疫的 5 头公牛中有 3 头在免疫后 14 天（PI）血清转化，最大滴度为 1：1600。所有 5 头免疫的公牛在 PI 第 21 天对 B. bovis 抗原均呈强阳性。接种牛的潜伏期直到挑战暴露后第 10 天才延迟，而 II 组和 III 组分别为 8 天和 7 天。所有组的牛均出现 41 度以上的发热；接种组 I 与 II 组和 III 组相比，红细胞压积减少无显著差异（P > 0.05）（分别为 29%、26%和 31%）。对照组的一头牛需要治疗。在研究期间，I 组和 II 组牛的体重平均增加 9 公斤和 7 公斤，而对照组牛的体重平均减少 4 公斤。用 rMSA-1-rMSA-2c-r12D3 蛋白免疫不足以预防对挑战的临床症状，但免疫反应足以保护牛免受温和的强毒力 B. bovis 株的侵害。
