Interleukin-6 expression in gut of parasite challenged sheep

Following challenge with Trichosirongylus colubrifonizis, increased numbers of T-cells and immunoglobulin responses are seen in the intestine of sheep immunised by repeated infection with live worms. IL-6 mRNA expression in t he small intestine from T. colubriformis-immunised and naive sheep was dete rmined by in situ hybridisation, whereas CD4(+), IgA(+), IgG(+) cells in th e gut were evaluated by immunohistochemistry. There was constitutive expres sion of IL-6 mRNA by cells in the naive gut, and the number of these cells was increased by parasite challenge. There were corresponding increases in numbers of CD4(+) and TCR gamma/delta(+) T-cells and IgG(+) B-cells. Our da ta are consistent with a role for IL-6, perhaps produced by CD4(+) and/or T CR gamma/delta(+) T-cells or B-cells, in B-cell terminal differentiation. I nfiltration of B-cells, particularly IgG(+) B-cells, may reflect parasite i mmunity in the host. (C) 2000 Elsevier Science B.V. All rights reserved.