猪胸膜肺炎放线杆菌血清1和5型交叉免疫保护研究

目的探讨猪胸膜肺炎放线杆菌(APP)不同血清型间交叉免疫保护的关系。方法以1型和5型APP参考菌株为实验对象,分别测定半数致死量(LD50),制备灭活细菌抗原和活菌抗原,免疫昆明小鼠,检测ELISA抗体水平及交叉免疫反应,并分别以10LD501型和5型APP菌进行攻击,观察小鼠保护力。结果1型和5型APP菌对小鼠的半数致死量分别为8.0×105.3和5.1×103.83CFU/LD50,死菌抗原和活菌抗原免疫小鼠均可产生高滴度抗体,且1型与5型间存在较强的交叉免疫反应。死菌抗原和活菌抗原免疫小鼠均能对本型APP菌攻击产生保护,保护率在80%以上。1型活菌免疫小鼠对5型菌攻击保护率为70%,5型活菌免疫小鼠对1型菌攻击保护率为90%,1型、5型死菌免疫小鼠对5型、1型菌交叉攻击均无保护作用。结论1型、5型APP活菌和死菌免疫小鼠均可对本型菌攻击产生保护,两型间存在较强的交叉免疫反应,但只有活菌免疫可以产生较好的交叉免疫保护,死菌免疫不能产生交叉免疫保护。

Cross Immunoprotection of Actinobacillus pleuropeumoniae Serotypes 1 and 5

Objective To explore the cross immunoprotection of Actinobacillus pleuropeumoniaeg(APP)of various serotypes.Methods Test for the LD50 of reference strains of APP serotypes 1 and 5 in mice.Prepare live and inactivated somatic antigens with the two strains separately.Immunize Kunming mice with the prepared antigens respectively and determine the antibody level by ELISA.Challenge the immunized mice crossly with APP serotypes 1 and 5,each at a dosage of 10 LD50,and observe the cross immunoprotection.Results The LD50 of APP serotypes 1 and 5 were 8.0×105.3 and 5.1×103.83 CFU,respectively.Both live and inactivated somatic antigens prepared with the two strains induced high antibody titers in mice,and strong cross immune response between serotypes 1 and 5 was observed.All the protective rates of live and inactivated antigens against challenge with APP of the same serotypes were more than 80%.The protective rate of antigen prepared with live APP serotype 1 against challenge with APP serotype 5 was 70%.However,the protective rate of antigen prepared with live APP serotype 5 against challenge with APP serotype 1 was 90%.Neither the antigens prepared with inactivated APP showed protection against challenge with APP of serotype 1 or 5.Conclusion Both live and inactivated somatic antigens prepared with APP serotypes 1 and 5 protected mice against challenge with APP of the same serotype,and strong cross immune response was observed between the two serotypes.However,only live somatic antigen induced good cross immunoprotection.