Establishment of a cell line from leucocytes of a cow with chronic lymphocytic leukemia.

A cell line was established from blood leucocytes of a cow with chronic lymphocytic leukemia. The leucocytes were cultured with conditioned medium (culture fluid of mouse cell line L). In vitro cell transformation was demonstrated by adaptation to permanent growth, modification of cell morphology, the alteration of cell surface phenotype, kinetic behaviour and the loss of the euploid stability of the cell karyotype. Ultrastructural studies showed rather a uniform cell pattern in a culture population heterogeneous for degree of cell vacuolization. A wide variation in the expression of surface markers in cells was demonstrated by E-, EA- and EAC-rosetting. In suspension culture the cell population was found to be sIg negative. Expression of leukemia-associated antigens by a fraction of the cultured cells was evidenced by a cytotoxic technique using complement and heterologous antisera against bovine leukemic lymphocytes, absorbed with normal lymphoid cells. Virus-like particles and BLV antigens were not identified. Culture cells failed to show spontaneous or antibody-dependent killer cytotoxicity. Comparison with blood lymphocytes of healthy and leukemic cattle was done. The established culture should be useful as a model for experimental immunology and oncology.

[Immunological study of the T- and B-lymphocytes in normal cows and in chronic lympholeukemia]. / Immunologicheskoe izuchenie T- i B-limfotsitov u korov v norme i pri khronicheskom limfoleikoze.

T- and B-lymphocyte populations from lymphoid organs and tissue of normal cattle and cattle with chronic lymphocytic leukaemia (CLL) were studied. Comparative studies of surface properties, quantitative parameters and heterogeneity of main T- and B-cell populations were performed. It must be noted that proliferation of B-lymphocytes, bearing surface IgM in blood, lymph nodes and spleen is closely connected with the progression of leukaemic process. An increased number of B-lymphocytes (2-3 times) with the receptors for complement was found. The proportion of T mu and T gamma cell subsets in CLL cows is distorted. The T gamma cell subset in T-cell suspensions from blood and spleen in CLL cows prevails in comparison with that in controls. The number of T mu cells in blood and lymph nodes in CLL is decreased.

[Determination of IgM and IgG on lymphocyte surfaces by means of registering rosette formation with anti-immunoglobulin-coated erythocytes]. / Opredelenie IgM i IgG na poverkhnosti limfotsitov metodom registratsii obrazovaniia rozetok s éritrotsitami, pokrytymi antiimmunoglobulinami.

To identify IgM and IgG on the surface of normal bovine B-lymphocytes, the test of antiglobulin-rosette formation (anti-Ig rosettes) was used. IgM and IgG were found to exist on separate B-lymphocyte populations. The composition of receptors on the surface of lymphocytes, forming Ig rosettes, was investigated. The distribution of these lymphocytes in bovine blood and lymphoid organs was determined. IgM and IgG were detected on the surface of thymocytes, their origin remains open to question.

T mu- and T gamma-cell subsets in normal and leukemic cattle.

T-cell subsets in the peripheral blood and lymphoid organs of normal and chronic lymphocytic leukemia (CLL) cattle were studied. Purified T lymphocytes were examined for the numbers of cells with the receptors for IgM (T mu) and IgG (T gamma). The expression of surface receptors on T mu- and T gamma-cell subsets was determined according to their capacity to bind different numbers of erythrocyte antibody complexes EAM or EAG. During the various times of preincubation of T cells at 37 degrees C, an increased release of receptors on the surface of T mu and partly T gamma cells was observed. For the optimal detection of bovine T mu cells, preincubation at 4 degrees C fro 24 h was necessary. The number of T gamma cells in the peripheral blood (P less than 0.001) and spleen (P less than 0.001) of CLL cattle was higher in comparison with controls. A considerably reduced number of T mu cells in the peripheral blood (P less than 0.001) and lymph nodes (P less than 0.02) of CLL cattle was observed. With the exception of thymus, T gamma cells from the lymphoid organs of CLL cattle had a higher expression of receptors than normal T gamma cells.