We report on the production and characterization of eight monoclonal mouse antibodies against the complete human VDAC "Porin 31HL". The antigen used was purified from a total membrane preparation of the transformed human B-lymphocyte cell line H2LCL.In Western blots all eight mAbs react with a single 31-kDa band in solubilized H2LCL membrane preparations thus demonstrating their specificity for the human VDAC 'Torin 31HL". Concerning the epitope specificity we show that all eight mAbs equally react with the N-terminal part of human porin.Moreover, we demonstrate the expression of VDAC in the sarcolemma by indirect immunoenzyme labelling of cryosections of human skeletal muscle applying four of our mAbs. These data support our recent observations on the expression of porin channels in the plasmalemma of different normal and transformed human cell lines.

Summary Antibody titers achieved by the immunization of hens are presented with examples. The transfer of immunoglobulins from the blood or oviduct to the egg and the distribution of these proteins in the various compartments which develop in the egg during incubation are quantitatively recorded. Possible procedures for extracting IgG antibody from the yolk are pointed out. Results concerning acid and temperature resistance of yolk antibodies are presented. An overview of the literature concerning with diagnostic use of yolk antibodies is given. The possible therapeutic application of egg antibodies is discussed. Zusammenfassung Das Hühnerei als Antikörperquelle Die durch die Immunisierung von Hühnern erzielten Antikörpertiter werden beispielhaft dargestellt. Der Transfer der Immunglobuline aus der Blutbahn bzw. dem Legeapparat in das Ei und die nachfolgende Umverteilung dieser Proteine in die sich während der Inkubation bildenden Eikompartimente werden quantitativ erfaßt. Die Möglichkeiten der IgG‐Antikörper‐Extraktion aus dem Dotter werden aufgezeigt. Ergebnisse zur Säure‐ und Temperatur‐Resistenz der Dotterantikörper werden vorgelegt. Eine Literaturübersicht bezüglich des Einsatzes von Dotterantikörpern wird gegeben. Der mögliche therapeutische Einsatz von Ei‐Antikörpern wird erörtert.

Clustering of the mast cell function-associated antigen (MAFA) on the surface of rat mucosal type mast cells line 2H3 (RBL-2H3) leads to suppression of the secretory response induced by the type I Fc epsilon receptor (Fc epsilon RI). In order to establish a possible association between MAFA and Fc epsilon RI we measured fluorescence resonance energy transfer (FRET) between the MAFA-specific monoclonal antibody (mAb) G63 and Fc epsilon RI-bound ligands as well as between Fc epsilon RI-bound ligands themselves using the donor photobleaching FRET (pbFRET) technique. Average FRET efficiencies between 6 and 9% were determined after low-temperature incubation with fluorescent dye conjugated mAb G63 bound to MAFA (donor) and IgE bound to Fc epsilon RI (acceptor) on RBL-2H3 cells. Subsequent cross-linking of IgE by a polyvalent antigen caused no change in FRET efficiencies. These results suggest that the MAFA is located in the vicinity of the Fc epsilon RI on resting cells, and that clustering of the Fc epsilon RI leads to no significant change in the proximity of the two molecular species. In view of the sequence motif identified in the cytosolic tail of the MAFA and the observed changes in its phosphorylation upon antigen stimulation (Guthmann et al., Proc. Natl. Acad. Sci. USA 1995, 92: 9397-9401), the present study suggests that the secretory response inhibition by MAFA interferes with the signal transduction cascade initiated via the Fc epsilon RI. An additional finding was that clustering of the Fc epsilon RI by antigen showed a clear increase in the efficiency of FRET between Fc epsilon RI-bound IgE molecules conjugated with fluorescent donor and acceptor.

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