RECOMBINANT HUMAN INTERLEUKIN-2 INDUCES PROLIFERATION AND IMMUNOGLOBULIN SECRETION BY BOVINE B-CELLS - TISSUE DIFFERENCES AND PREFERENTIAL ENHANCEMENT OF IMMUNOGLOBULIN-A

Recombinant human interleukin 2 (rhIL2) was found to have activity on bovine B-cells in vitro, inducing both their proliferation and differentiation into immunoglobulin secreting cells. Only low and medium density (activated) B-cells were responsive; high density (resting) B-cells did not respond to rhIL2. Proliferative responses by unfractionated and purified B-cell populations were similar for all tissues tested. In contrast, immunoglobulin secretion was stimulated to a greater degree in prescapular lymph node (PSLN) and bronchial lymph node (BLN) cells than in mesenteric lymph node (MLN) cells and splenic lymphocytes on culture with IL2. All isotypes were stimulated equally in the case of PSLN, BLN, and splenic lymphocytes. However, culture of unfractionated MLN lymphocytes with IL2 resulted in enhanced secretion of IgA relative to the other isotypes. Removal of T-cells and accessory cells from the MLN lymphocyte preparation resulted in this effect being lost.