Localization of Immunological Complexes Fixing Ss1c (C3) in Germinal Centers of Lymph Nodes

Abstract

28 human and 60 experimentally stimulated rabbit lymph nodes were studied by means of light microscopy and immunofluorescence. 21 of the 28 human lymph nodes showed well-developed germinal centers. IgM, IgG, and the ß1C component of complement were found in the same distribution within germinal centers when examined in serial cryostat sections. 36 rabbits were stimulated with Brucella antigen, and 24 rabbits with BSA. A strikingly consistent correlation between distribution and appearance of specific staining for rabbit ß1C, IgM, and IgG was observed; when lymph nodes were stimulated with BSA, antigen and specific antibody were present. Treatment of unfixed sections with citrate-buffered saline at low pH resulted in complete elution of immunoglobulins, ß1C, and BSA from rabbit germinal centers, and in marked diminution of IgG and IgM in human germinal centers, while at the same time plasma cells remained strongly fluorescent. Specific selective fixation of heterologous (human) complement in rabbit germinal centers positive for ß1C, IgG, IgM, and BSA was also obtained. These data present strong evidence for the existence within germinal centers of antigen-antibody complexes which fix at least the ß1C component of complement in vivo. The possibility of complete elution of immunoglobulins from rabbit germinal centers can be taken as evidence that, at least for 20 days after primary and secondary stimulation, a major component of the immunoglobulins present in germinal centers is not produced locally but accumulates at the surface of cells.

Immunofluorescent Localization of Antihemophilic Factor Antigen and Fibrinogen in Human Renal Diseases

“…to human IgG, IgM, IgA, C3 (,B-1C globulin), fibrinogen, and albumin by the direct technique as previously described (14,15). Sections were stained with rabbit antihuman AHF and rabbit antihuman a-2 macroglobulin by the indirect technique using fluorescein-conjugated monospecific goat antirabbit IgG as previously described (13).…”

Glomerular deposition of properdin in acute and chronic glomerulonephritis with hypocomplementemia

“…Tissue from 97 patients was available for this study. Rabbit antisera produced according to methods previously described (7,8) were tagged with fluorescein isothiocyanate (FITC) by the method of Wood, Thompson, and Goldstein (9), as modified in our laboratory (8). Two FITC-tagged antisera to human C3 were used, one prepared by immunizing rabbits with human 81C isolated according to Miiller-Eberhard, Nilsson, and Aronsson (10) (referred to in this publication as anti-flC), the other with 81C absorbed to zymosan (11) (referred to as anti-fi1C-Z).…”

“…After 5 wk a booster injection was given and the rabbits were bled on several occasions. IgG was isolated from the antiserum and labeled with FITC (8,9). The specificity of the anti-properdin, anti-p1,C and anti-,fiC-Z sera was studied by absorption, double diffusion in agar (14), and immunoelectrophoresis (15 Table I.…”

Role of Complement in Induction of Antibody Production in Vivo

“…The discovery of an interaction between lymphocytes and the fixed C3 component of complement (2)(3)(4)(5), and the demonstration by Nussenzweig et al that C3 receptors are a feature of B-cell populations (6)(7)(8)(9)(10), raise the possibility that C3 might play a part in this process (11). Germinal centers of lymphoid tissue, in which the induction of antibody production m a y occur, contain B cells, fixed C3, and complexes capable of fixing C3 (12). I have previously shown that treatment of mice in vivo with the C3-cleaving protein of cobra venom (CoF) 1 suppresses thymus-dependent but not thymus-independent antibody production, suggesting a possible role for C3 in lymphocyte cooperation (11).…”