Summary of workshop findings for porcine B-cell markers

Based on cluster groups from the first-round analyses of the Third Internat ional Swine CD Workshop, 38 monoclonal antibodies (MAbs) including eight in ternal controls were analysed by flow cytometry (FCM) and immunohistochemis try (IH) in the second-round analysis of the B-cell section of this worksho p. Targets in this section included peripheral blood lymphocytes and cells isolated from ileal Peyer's patches (PP), mesenteric lymph nodes (MLN) of a dult animals, bone marrow cells from newborn piglets and thymus cells isola ted from foetuses at day 105 of gestation. Immunohistochemistry of these 38 MAbs identified four sets, whose ligands w ere co-expressed with CD21, which showed a tissue distribution compatible w ith specificity for cells including those of the B-cell lineage. Another gr oup of miscellaneous antibodies appeared to identify other cells, several a ntibodies were negative. Two-colour flow cytometry (2C-FCM) was carried out by pairing each antibody of interest with antibodies to SWC7, CD21, sIgM a nd a polyclonal rabbit anti-swine immunoglobulin antiserum (RaSwIg). The anti-CD21 MAb BB6-11C9 (no. 20) and IAH-CC51 (no. 19), established in p revious workshops, as well as the cross-reactive anti-human CD21 B-ly4 (no. 146), clustered together in FCM analyses of the first round and showed sim ilar cellular distribution in IH. A further cluster was formed by the stand ard CC55 (no, 55) and 2A10/8 (no. 102) submitted as SWC7 specific. The seco nd SWC7 standard 2F6/8 (no. 100) clustered separately, but IH showed an ide ntical pattern of reactivity to the other SWC7 MAb. Unfortunately, this work could not identify any other novel clusters with s pecificity for B-cells, as the statistical clustering of other MAbs could n ot be substantiated by IH or subsequent two-colour-FCM work. However, we co uld identify MAb with similar cellular distribution. The ligands for the cr oss-reactive anti-human CD40 G28.5 (no. 25) and STH224 (no. 153) were expre ssed on very similar targets, similarly the ligands for the MAb pair JM1H1 (no. 139) with BB6-10A10 (no. 142) and the MAb pair 3F7/11 (no. 115) with 1 C2F10 (no. 187). (C) 2001 Elsevier Science B.V. All rights reserved.