Immunochemical and biochemical study of an abnormal heavy chain of bovine IgG1.

An abnormal heavy chain (HC) protein of IgG1 was isolated from the serum of a leukemic cow by gel filtration on a Sephadex G-200 column with the following ion-exchange chromatography. The HC protein migrated electrophoretically in the anodic region. The molecular weight of the untreated HC protein was about 48,000. Enzymatic treatment with papain and reduction with beta-mercaptoethanol showed no effect on the protein. Antigenic analysis of the HC protein using a specific rabbit antiserum against bovine IgG1 showed a complete identity with the Fc fragment and a partial identity with the intact bovine IgG1. Antigenic determinants of the light-chain were not found. The HC protein consisted of only one polypeptide chain.

[The cytological and immunological characteristics of a virus-producing FLK 44/2 culture]. / Tsitologicheskaia i immunologicheskaia kharakteristika virusprodutsiruiushchei kul'tury FLK 44/2.

Results obtained from cytological and immunological analysis of FLK 44/2 cells indicate the transformation and heterogenization of BLV-producing cell culture. Karyotypic changes of the culture were observed, as well as alterations in its antigenic specificity leading to antigenic diversion. The cell population displayed a high proliferation activity limited by topoinhibition and culture medium exhaustion. An immunocytochemical investigation of virus-producing cell population, using monoclonal and polyclonal antibodies against BLV revealed various cellular forms of BLV-expression. A possibility is discussed to use the immunological approach for selection and establishment of cellular clones exhibiting appropriate virus production parameters.

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.