Rosette tests for T and B lymphocyte immunoglobulin

Demonstration of T4, T8, M1 and B7 determinants on human T cells with a rosette test: implications for the assay specificity of monoclonal antibodies

Under optimal test conditions significantly more freshly isolated human T cells reacted with OKT4, OKT8, OKM1 and OKB7 monoclonal antibodies (Mabs) in the indirect antiglobulin rosetting reaction (IARR) than by indirect immunofluorescence. Rabbit erythrocytes (E) coated with anti-mouse immunoglobulin were more sensitive indicator cells in the IARR than similarly coated sheep E. Treatment of T cells with neuraminidase further enhanced T cell reactivity in the IARR with each Mab so that an average of 60% or more of T cells were T4+, T8+ and M1+ and at least 40% had the T4+ T8+ phenotype. The various findings suggest that the rosette assay detects determinants on T cells that are expressed below the detection threshold of immunofluorescence. Moreover, these findings indicate that the cellular specificities of a particular Mab may change when one assay system is substituted for another or when the protocol of a particular assay is altered.

Surface immunoglobulin restriction in B-non Hodgkin's lymphomas in cell suspension and on frozen tissue sections

The diagnostic relevance of different tests for detection of surface immunoglobulin on tumour cells of B-type non-Hodgkin's lymphomas (B-NHL) was investigated by comparison of the direct antiglobulin rosetting reaction (DARR) in suspension with two-colour direct immunofluorescence (DIF) on frozen tissue sections. In benign lymph nodes (n = 27) the kappa/lambda ratio by DARR test ranged from 0.9 to 2.8. Tested by suspension and frozen tissue analysis, light chain restriction was found in 24 and 27 of 31 cases of B-NHL, respectively. Heavy chain restriction was found in half of the cases (14 of 26) studied in suspension and in almost all (28 of 31) tested on sections. In 9 cases DARR tests showed restriction of more than one Ig class on tumour cells, which was infrequent (2 of 28) in frozen section analysis. Although both tests appeared valuable for routine diagnostic purposes, we found the DIF analysis on tissue sections somewhat more discriminative, especially in detection of heavy chain restriction in B-NHL.

The demonstration of sIg, MHC and T cell antigens and Fc receptors on the lymphocyte surface by anti-globulin rosetting reactions: some technical considerations

The previously shown marked difference in sensitivity of antiglobulin rosette formation and immunofluorescence was confirmed in detection of varying amounts of anti-Ig bound to B cells. The direct and indirect rosette method revealed twice the number of sIg+ cells shown by direct immunofluorescence (DIF), and at least an order of magnitude more antibody on the cell surface is necessary to detect the conventional B cells (shown by DIF) by indirect immunofluorescence compared with indirect antiglobulin (IARR) rosette formation. Variants of the sensitive IARR test were developed to reveal general lymphocyte, MHC class I and class II and T cell-specific antigens and Fc receptors using xenogeneic or allogeneic reagents. Sensitive indicator cells were used which form almost no rosettes with unsensitized lymphocytes although coated with IgG which would otherwise bind to the Fc receptor. The suggestion that chromic chloride treatment inactivates the relevant Fc determinants was supported by experiments showing the failure of IgG antibody-sensitized bovine RBC (standard Fc indicator cells) to form rosettes after treatment with chromic chloride.

Universal rosetting reagent for the detection of human cell surface markers

The extensive use of monoclonal antibodies for the detection of human cell surface markers has necessitated the development of a simple, reproducible reagent which can be applied universally to any mouse anti-human antibody. We have developed a rosetting reagent which is composed of ox red blood cells, rabbit anti-ox RBC antibody, protein A, and rabbit anti-mouse Ig antibody. This reagent binds specifically to human lymphocytes coated with mouse monoclonal antibody, is as sensitive as immunofluorescence and gives comparable results with fresh and frozen peripheral blood lymphocytes. Sensitivity, reliability, and ease of quantitation make this an extremely practical reagent, and its versatility makes it especially useful for large scale studies of human T cell markers.