IB(M41株)种毒代次和免疫原性的关系

评估不同代次IBV M41株种毒是否可以作为生产用种子。将M41株种毒用SPF胚连传8代，从中选出第3、第5、第7代，测定其EID50。并用此3代M41株鸡胚尿囊液制毒的油乳苗免疫易感鸡，以HI试验检测其抗体水平。3种疫苗免疫鸡均保护9/10以上，对照鸡全发病；对免疫后与免疫前HI抗体水平的比较表明，免疫后抗体平均滴度提高3倍以上。不同代次的M41毒株的免疫原性仍然保持良好，可以正常用来制造疫苗和建立种子批。

The Relation between the Virus-seed of Infectious Bronchitis Virus(M41) and its Immunogenicity

Whether different generations of IBV M41 strain could be used as seed for producing vaccine was evaluated. In this article IBV M41 strain was handed down from 1 to 8 generation. The 3rd, 5th and 7th offsprings were chosen for evaluating their immunogenicity by detection of their EID50. Vaccines to the three generations were prepared and used for inoculating the SPF chicken. The results indicated that the three vaccines could protect the birds and the protection rate was all above 9/10. The controls were infected and showed signs of the disease. The antibody titers of them were assayed at post-inoculation and the results indicated that the mean antibody titer rose to 3 times of that of the pro-inoculation. Different generations of IBV M41 strain still kept good immunogenicity and could be used as product seed for preparing IB vaccines.