Connexin 43 Communication Channels in Follicular Dendritic Cell Development and in Follicular Lymphomas

Figure 2

Treatment of low density cell fractions of reactive human tonsils in culture using 200 µM Gap27 connexin mimetic peptide. (a) At the start (0 h) round cells are dispersed, some of them coexpressing Cx43 and either IgG or IgM (arrows). In control (untreated) cultures (1st row) at 2 h, FDC processes decorated with Cx43 (arrows) enmesh round B cells. By 6 h clusters are formed of 10–15 FDC and B cells which grow up to ~50 cells by 16 h, with Cx43 plaques detected at the cell borders (arrows). In Gap27 treated cultures (2nd row) the cluster formation is seriously compromised resulting in cells of vacuolated cytoplasm (arrow) and shrunken nuclei. (b) A “healthy” FDC-B cell cluster of ~8–10 cells (some are encircled) with Cx43 particles (red) colocalizing in B cell membranes (yellow, arrows) with sheets of CD35 positive FDC (green), which envelop them. Immunofluorescence single and double labeling and Nomarski differential interference combined with nuclear staining using either 7-aminoactinomycin D ((a), red) or Hoescht ((b), blue). (c) Graph showing significantly (; ) reduced cell numbers within clusters after Gap27 treatment compared either to untreated or scrambled-probe treated cultures. Results in graphs show the mean and standard deviation of at least three independent experiments. Scale bar shows 50 µm, except in the untreated Cx43 labeled cultures (upper row) where it is 25 µm. In the left row middle panels it equals 15 µm and 10 µm in the bottom panel.

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