MSB-1 Cells Research Articles

Properties of a Chicken Lymphoblastoid Cell Line From Marek's Disease Tumor

Properties of a chicken lymphoblastoid cell line (MSB-1) from a Marek's disease tumor were studied. The cell line grew well at 41 degrees C in medium RPMI-1640 supplemented with 10% bovine fetal serum and had a doubling time of 8-12 hours. Cells grown in stationary suspension culture did not attach to the vessel and had the morphology of typical lymphoblasts. At 37 degrees C, the cell line grew initially but ceased to divide after several subcultures. In the subcultures maintained for 48-72 hours, 1-2% of the cells produced Marek's disease virus (MDV)-specific intracellular and mambrane antigens and contained herpesvirus particles when examined by the electron microscope. Cocultivation of these cells with duck or chicken embryo fibroblast cultures resulted in transfer of infection and production of microplaques typical of MDV. Peripheral nerve lesions and lymphoid tumors characteristic of Marek's disease were caused by inoculation of susceptible chicks with MSB-1 cells or duck cells infected with strain BC-1 of MDV recovered from the MSB-1 cell line. No specific tumors were produced at the site of inoculation, and infection was readily transmitted to cagemates. Tumors were also produced in the skeletal muscles and seemed to be largely virus induced. MSB-1 cell line was free of C-type virus particles.

1436. A plate-stator vacuum pump: I G Khisameev et al, Soviet Patent, class F 04, c 25/02, No 370, 367, claimed 4/1/71, published 15/2/73 ( in Russian)

The avian hematopoietic system has long been an invaluable model to study the mechanisms of cell growth and differentiation. We have developed six MAbs against either chicken embryonic hematopoietic precursor cells or retrovirus-transformed cells. MAbs Mo1, Mo2, and Mo3 recognized transformation-associated markers expressed in AMV-transformed nonproducer cell line-BM2. Not only were these markers expressed 7 to 10 folds higher on BM2 than on normal monocytic cells, but their expression was drastically reduced when BM2 cells were induced to differentiate into macrophages by PIMA. The control of marker expression is associated with v-myb-transforming cascade, since another monocytic lineage-specific oncogene, v-myc, did not enhance the expression of these markers. MAb Emi detected a marker that is normally present in 20% of the cells from the 3050% interface of a discontinuous percoll gradient of normal 4-day-embryo yolk sac. Its expression is also found in AEV-transformed cells and MSB1 cells. The epitope for Em1 was exposed after neuraminidase treatment on erythroleukemia cell line 6C2, which suggested that sialylation and/or glycosylation is pivotal in regulating the expression of specific markers in differentiation pathways during embryogenesis and tumorigenesis. MAb Em2 recognized proliferating hematopoietic cells after the fourth day of embryogenesis. MAb Em3, on the other hand, is presumed to be specific for an oncofetal antigen expressed in various transformed cells but only in 10% of the cells from 30/50% interface of a discontinuous percoll gradient of normal 4-day-embryo yolk sac. These MAbs will be useful for dissecting the expression of differentiation markers within normal versus abnormal differentiation pathways in molecular terms.

Cytological, cytogenetic and ultrastructural studies of rat cell lines carrying avian and murine sarcoma genomes.

Two rat cell lines (RSK 4 and XC) which carry the RSV genome but do not produce infectious virus were studied together with a control rat cell line (LW 13). One rat cell line (MSB-1) which carries the MSV genome and produces infectious particles was also studied. The cells carrying viral sarcoma genome showed pleomorphic cytology. All cell lines showed acid phosphatase positivity, indicating the presence of lysosomes, but only cells of the MSB-1 line contained glycogen granules. Cytogenetic studies revealed a wide range of chromosomal changes. Most cells carrying sarcoma viral genome contained large metacentric and/or submetacentric “marker” chromosomes. Such chromosomes are not present in normal rat cells even after prolonged in vitro cultivation. Many of the RSK 4 cells showed a chromosome number ranging between 70 to 80, while XC cells showed a pseudodiploid pattern with a chromosome number around the normal. About half the MSB-1 cells contained between 50–60 chromosomes.