Characterization of the production of monocyte chemoattractant protein-1 and IL-8 in an allogeneic immune response.
Delayed-type hypersensitivity and allograft rejection are dependent upon the generation of Ag-specific T cell immune responses. The mixed lymphocyte reaction is a model of alloantigen-driven immunity and has provided significant insight into the mechanisms of T cell proliferation. Recently, soluble mediators, including TNF-alpha have been shown to be involved in the full expression of this response. In order to elucidate the potential mechanisms of cellular recruitment in the context of either delayed-type hypersensitivity or allograft rejection, we employed a mixed lymphocyte reaction to study the production of chemokines, monocyte chemoattractant protein-1 (MCP-1), and IL-8. Time-course experiments demonstrated that significant levels of MCP-1 and IL-8 were produced in allogeneic cultures as early as day 1, and that this relationship persisted over 6 days in culture. Northern blot analysis of chemokine mRNA confirmed the early induction of these genes in the allogeneic response. The levels of MCP-1 and IL-8 protein from mixed lymphocyte reaction supernatants as measured by specific ELISA were positively correlated with the proliferative response as measured by [3H]TdR uptake. Although significant MCP-1 and IL-8 were produced during a mixed lymphocyte reaction, these molecules did not participate in the proliferative response, as neutralizing antibodies to either MCP-1 or IL-8 had no effect on proliferation. In order to ascertain the mechanism for the induction of MCP-1 and IL-8 during the mixed lymphocyte reaction, experiments were performed in the presence of neutralizing anti-human TNF antibodies. Neutralization of TNF resulted in significant abrogation of MCP-1 and IL-8 production (75 +/- 5 and 87 +/- 2 percent, respectively). Cells isolated from the mixed lymphocyte reaction at day 6, demonstrated that MCP-1 and IL-8 Ag were localized to mononuclear phagocytes. These results demonstrate that potent chemokines, MCP-1 and IL-8, are produced during the evolution of a mixed lymphocyte reaction, and their induction is TNF-dependent.
Christensen
P J
PJ
Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0360.
Rolfe
M W
MW
Standiford
T J
TJ
Burdick
M D
MD
Toews
G B
GB
Strieter
R M
RM
D001483:Base Sequence; D018932:Chemokine CCL2; D002630:Chemotactic Factors / Q000502:physiology*; D015870:Gene Expression; D006801:Humans; D007111:Immunity, Cellular; D016209:Interleukin-8 / Q000502:physiology*; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D012333:RNA, Messenger / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
D018932:Chemokine CCL2; D002630:Chemotactic Factors; D016209:Interleukin-8; D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha