Studies on the defense mechanisms of the silkworm, Bombyx mori, against the replication of a nuclear polyhedrosis virus in continuous cell cultures

通过对家蚕幼虫或蚕蛹的抗原刺激，研究了家蚕对核型多角体病毒(NPV)感染的防御机制。本研究的目的是探讨家蚕Bombvx mori连续培养细胞(S.P.C.Bm36细胞和BM-N细胞)对NPV复制的防御机制。1)疫苗由S.P.C.BM 36细胞来源的NPV(非包涵体病毒)经福尔马林处理或紫外线照射制成。分别在接种NPV前2小时和24小时将疫苗接种于培养细胞。BM 36细胞和BM-N细胞均未表现出明显的防御反应。2)在接种NPV前24小时和48小时，分别加入来自S.P.C.BM 36细胞的家蚕非囊状病毒免疫兔血清，均不能识别被动免疫。另外，分别在接种B.NPV后的即刻和60min加入抗NPV血清。3)检测了非允许病毒对允许病毒在果蝇细胞(IPLB-SF-21AEII)中复制的干扰作用。将对果蝇细胞不允许的家蚕核型多角体病毒(B.mori NPV)接种于细胞培养物中，分别在0和60min后接种对果蝇细胞不允许的新城疫霉菌(Xstia c-nierum)。然而，家蚕核型多角体病毒对黑斑核型多角体病毒的干扰作用尚未被认识。

The investigations on the defense mechanism of the silkworm against the infection of a nuclear polyhedrosis virus (NPV) have been done by means of antigenic stimulation to silkworm larvae or pupae. However, the defense reaction has not been easily demonstrated.The objective of the present study is to investigate the defense mechanism against NPV replication in Bombvx mori continuous cell cultures (S. P. C. Bm36 cells and Bm-N cells).1) The vaccines were made from the NPV (nonoccluded virus) derived from S. P. C. Bm 36 cells by treatment with formalin or irradiation with UV. The vaccine was inoculated to cultured cells 2 and 24 hr, respectively, before the inoculation of NPV. However, the induction of the defense reaction was not shown in both of S. P. C. Bm 36 cells and Bm-N cells.2) The passive immunity, , could not be recognized when the immunized rabbit serum against B. mori NPV (nonroccluded virus) derived from S. P. C. Bm 36 cells was added to the cell culture 24 and 48 hr, respectively, before the inoculation of NPV. In addition, the anti-NPV serum was added to the cell culture immediately and 60 min, respectively, after the inoculation of B. . mori NPV, however, the defense effect of the anti-NPV serum against the replication of the intracellular virus was not demonstrated.3) The interference of nonpermissive virus with the replication of permissive virus in Spodoptera frugiperda cells (IPLB-SF-21AEII) was tested. B. mori NPV which is a nonpermissive against S. frugiperda cell was inoculated to the cell culture, then after 0 and 60 min, respectively, Xestia c-nierum NPV which is permissive against S. frugiperda cell was inoculated. However, the interference of B. mori NPV with X. c-nigrum NPV was not recognized.