Mononuclear peripheral blood lymphocytes (PBL) from patient with infectious mononucleosis (IM) were tested in a 51Cr-release assay for cytotoxicity against autologous and allogeneic lymphoblastoid cell line (LCL), or Epstein-Barr virus (EBV)-genome positive and negative cell line. In acute phase, PBL lyse an autologous LCL as well as allogeneic LCL (Wa cells). High levels of cytotoxicity were observed in the combinations between effector and target cells sharing HLA-Class 1 product. EBV-genome positive Daudi and Raji cells which lack HLA-Class 1 antigen and have mismactched HLA-Class 1 antigen, respectively showed resistance to killing. EBV-genome negative tumor cells except NK sensitive K562 cells were not killed by IM lymphocytes. However, the IM lymphocytes without atypical form in convalescent phase failed to show killing activity against autologous and allogeneic LCL. These findings suggest that cell surface membrane antigen structure on EBV-infected LCL may be able to explain the recognition and triggering of lysis of target cells by HLA-Class 1 restricted cytotoxic T cells (CTL) from acute IM. Phenotypic analysis of PBL with atypical form from IM was made by two-color flow cytometry. The data demonstrate that CD8+ T cells quantitatively represent the major population of lymphocytes expanded during acute IM. Furthermore, approximately 70% of these CD8+ T cells express HLA-DR on these surface, suggesting that they have undergone activation. However, IL 2R (CD25 antigen) expression was not significantly elevated on activated T cells. The salient profile on cytofluorographs of an acute IM was the increased number of CD3+CD19-, CD8+CDllb-, CD8+CD28+ and CD8+S6F1+ cells. However, CD3-CD19+, CD8+CDllb+, CD8+S6F1-, CD4+Leu8-and CD25+HLA-DW antigens were little expressed. Increased number of CD8~CDllb-, CD8+CD28+ and CD8+ S6F1+ cells, which are regarded as CTL were reduced according to the improvement of the clinical symptoms and laboratory findings. These results together with HLA typing analysis suggested a possibility HLA-Class 1 restriction of the CTL with surface phenotype of CD8+CDllb-, CD8+CD28+, and CD8+S6F1t cytotoxic T cells (CTL) ; CD8 T cells ; HLA ; Epstein-Barr virus

No abstract

No abstract

Hamster-complement-C1s cDNA was inserted into an expression plasmid BCMGSNeo (BCMGSNeoHACS). BALB/c mouse fibroblast A31 cells, which do not produce C1s, were transfected with BCMGSNeoHACS and the transfectants were selected with G418. Normal C1s production by the transfectants was confirmed by Northern and immunoblot analysis and by an esterase assay. To examine the tumorigenicity of the transfectants, 1 x 10(6) cells were injected s.c. into 6-week-old BALB/c nu/nu mice. Three C1s cDNA transfectants (A3CS9, A3CS12, A3CS13) formed tumors whereas both A31 and A31 transfected with the vector alone (A3BCM1 and A3BCM3) did not. The tumors derived from the transfectants showed invasive growth, and many capillaries were observed in the tumors. A tumor derived from A3CS13 was examined immunohistochemically and found to be reactive with an anti-C1s monoclonal antibody. Tumor cells were cultured in vitro again and C1s secreted into the culture medium was examined by immunoblot analysis. C1s synthesized by the tumor cells derived from A3CS13 maintained its biological functions. Tumor cells derived from A3CS9 and A3CS12 cells, however, produced C1s having abnormal disulfide bonds.

No abstract