CD4-Dependent Generation of Dominant Transplantation Tolerance Induced by Simultaneous Perturbation of CD154 and LFA-1 Pathways

Abstract

CD154 and LFA-1 (CD11a) represent conceptually distinct pathways of receptor/ligand interactions (costimulation and adhesion/homing, respectively) that have been effectively targeted to induce long-term allograft acceptance and tolerance. In the current study, we determined the relative efficacy and nature of tolerance induced by mAbs specific for these pathways. In vitro analysis indicated that simultaneous targeting of CD154 and LFA-1 resulted in profound inhibition of alloreactivity, suggesting that combined anti-CD154/anti-LFA-1 therapy could be highly effective in vivo. Thus, we evaluated combining mAb therapies targeting CD154 and LFA-1 for inducing transplantation tolerance to pancreatic islet allografts. Monotherapy with either anti-CD154 or anti-LFA-1 was partially effective for inducing long-term allograft survival, whereas the combination resulted in uniform allograft acceptance in high-responder C57BL/6 recipients. This combined therapy was not lymphocyte depleting and did not require the long-term deletion of donor-reactive T lymphocytes to maintain allograft survival. Importantly, combined anti-CD154/anti-LFA therapy uniquely resulted in "dominant" transplantation tolerance. Therefore, simultaneous perturbation of CD154 and LFA-1 molecules can result in profound tolerance induction not accomplished through individual monotherapy approaches. Furthermore, results show that such regulatory tolerance can coexist with the presence of robust anti-donor reactivity, suggesting that active tolerance does not require a corresponding deletion of donor-reactive T cells. Interestingly, although the induction of this regulatory state was highly CD4 dependent, the adoptive transfer of tolerance was less CD4 dependent in vivo.

Targeting LFA-1 Synergizes with CD40/CD40L Blockade for Suppression of Both CD4-Dependent and CD8-Dependent Rejection

“…This is consistent with a recent report showing that dual targeting of LFA-1 and CD40/CD40L successfully regulates islet allograft rejection which is CD4-dependent but CD8-independent (45). In our studies, we noted that short-term dual targeting of LFA-1 and CD40/CD40L synergistically suppressed hepatocyte-induced CD4-dependent and CD8-dependent T-cell-initiated rejection responses.…”

Direct continuities between cisternae at different levels of the Golgi complex in glucose-stimulated mouse islet beta cells

“…Intact islets of Langerhans obtained from the pancreata of freshly killed adult, female, BALB͞c mice, were used to ensure that neither cellular polarity nor extracellular matrices were disrupted. Islets were isolated by treatment with collagenase (Sigma type V, lot tested) by means of intraductal injection, and were purified with a Histopaque-1119 density gradient (Sigma) (16,17). Islets were hand-picked to minimize contamination by residual acinar tissue then cultured in RPMI medium 1640 containing 10% (vol͞vol) heatinactivated FBS and 7 mM D-glucose equilibrated with 5% CO 2 at 37°C.…”

Spontaneous Allograft Tolerance in B7-Deficient Mice Independent of Preexisting Endogenous CD4+CD25+ Regulatory T-Cells

“…It is of interest that in other studies of allograft tolerance we have generally found the reciprocal finding. That is, while operationally tolerant animals can both demonstrate donor and third-party reactivity in vitro, they nevertheless demonstrate donor-specific tolerance in vivo (37,38). Currently, the disparity between these two assessments of tolerance is not completely clear.…”