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The Influence of Antigen Density and a Comparison of IgG and IgM Antibodies in the Anti‐Complementary Modulation of Lymphocytic Surface Immunoglobulin
Author(s) -
GORDON J.,
ANDERSON V. A.,
ROBINSON D. S. F.,
STEVENSON G. T.
Publication year - 1982
Publication title -
scandinavian journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.934
H-Index - 88
eISSN - 1365-3083
pISSN - 0300-9475
DOI - 10.1111/j.1365-3083.1982.tb00635.x
Subject(s) - antibody , antigen , microbiology and biotechnology , lysis , surface immunoglobulin , chemistry , biology , immunology , b cell
Experiments were carried out to determine the influence of antigen density on anti‐complementary modulation, defined here as the conferring by anti‐immunoglobulin (Ig) of resistance to lysis of guinea pig L 2 C leukaemic lymphocytes through anti‐Ig plus syngeneic complement (C). Populations of leukaemic cells, varied widely in their quantitative expression of surface membrane Ig as judged by the binding to cells of 125 I‐labelled Fab’ fragments from anti‐Ig, and a good correlation between the bulk antigen density and the percentage of cells lysed by anti‐Ig plus C was obtained ( P =0.02). In the presence of 10m m sodium azide, which has been shown to diminish ihe modulation occuring during simultaneous incubations with anti‐Ig and C, this correlation was even stronger ( P < 0.001). No zone could be defined in which the level of surface Ig expression was sufficient to serve complement lysis but too low for modulation. Furthermore, both the degrees and rates of modulation occurring on incubation with antibody at 37°C, either before C addition or in the presenee of lytic C, were similar for populations of high, low, or intermediate antigen density. Separation of cells by their size or density failed to yield populations differing in either their susceptibility to humoral killing through anti‐Ig or their modulating capacity. IgG and IgM antibodies to the L 2 C cell surfce Ig evoked similar levels of killing with syngeneic C, and when compared for their ability to promote anti‐complementary modulation, no difference was revealed in either the rule or degree of modulation occurring during incubations at 37°C with the two isotypes. The findings are discussed with particular reference to observations on the modulation of mouse thymus leukaemia (TL) antigens.