Itoh Akira, Gotanda Tohru
Research Center for Veterinary Science, The Kitasato Institute, Kitamoto, Saitama, Japan.
J Vet Med Sci. 2002 May;64(5):405-11. doi: 10.1292/jvms.64.405.
Protective effects of recombinant R7 (rR7) vaccine against Leucocytozoon caulleryi in chickens were studied. After injection of oil-adjuvanted rR7 vaccine into chickens, antibody titers against second-generation schizonts (2GS) antigen of L. caulleryi (anti-2GS antibody) rapidly rose in all the immunized chickens, reached to a peak value 2 weeks after injection, and the titers persisted through 4 or 5 months after injection. Chickens having high levels of the anti-2GS antibody titers (> or = 102,400 ) at pre-challenge completely protected against sporozoites challenge of L. caulleryi. After the challenge inoculation, relatively high parasitemia of L. caulleryi was observed in all the inadequately immunized chickens having low levels of the antibody titers (< or = 3,200) at pre-challenge, although some of them seemed to be clinically normal. Correlation of protective effects in the immunized chickens was observed between both prevention of appearance of clinical signs and parasitemia after parasites challenge and anti-2GS antibody titers of the chickens at pre-challenge. The present study shows that chicken leucocytozoonosis can be prevented by vaccination, and humoral immunity may play an important role in the control of chicken leucocytozoonosis.
研究了重组R7（rR7）疫苗对鸡卡氏住白细胞虫的保护作用。给鸡注射油佐剂rR7疫苗后，所有免疫鸡体内针对卡氏住白细胞虫第二代裂殖体（2GS）抗原的抗体滴度（抗2GS抗体）迅速上升，注射后2周达到峰值，且滴度在注射后持续4或5个月。攻毒前抗2GS抗体滴度高（≥102,400）的鸡完全抵御了卡氏住白细胞虫子孢子的攻击。攻毒接种后，在所有攻毒前抗体滴度低（≤3,200）的免疫不足的鸡中均观察到相对较高的卡氏住白细胞虫血症，尽管其中一些鸡似乎临床正常。在免疫鸡中，观察到攻毒后临床症状和虫血症的出现预防与攻毒前鸡的抗2GS抗体滴度之间存在保护作用的相关性。本研究表明，通过疫苗接种可预防鸡住白细胞虫病，体液免疫可能在鸡住白细胞虫病的控制中起重要作用。
