Delayed administration of anti-PD-1 antibody reverses immune dysfunction and improves survival during sepsis - PubMed (original) (raw)

Delayed administration of anti-PD-1 antibody reverses immune dysfunction and improves survival during sepsis

Pavan Brahmamdam et al. J Leukoc Biol. 2010 Aug.

Abstract

There is increasing recognition that a major pathophysiologic event in sepsis is the progression to an immunosuppressive state in which the host is unable to eradicate invading pathogens. Although there are likely numerous causes for the immunosuppression, expression of negative costimulatory molecules on immune effector cells is a likely contributing factor. PD-1 is a recently described, negative costimulatory molecule that has potent effects to inhibit T cell activation, cytokine production, and cytotoxic functions. PD-1 plays a critical role in the host response to specific pathogens, but relatively little work has been done on the possible effects of PD-1 in sepsis. We hypothesized that the anti-PD-1 antibody would improve survival in sepsis. Mice underwent CLP, and PD-1 expression was quantitated. Additionally, the effects of anti-PD-1 antibody on lymphocyte apoptosis, cytokine production, host immunity, and survival were determined. PD-1 expression increased beginning 48 h after sepsis, and >20% of CD4 and CD8 T cells were positive by 7 days. Anti-PD-1 antibody administered 24 h after sepsis prevented sepsis-induced depletion of lymphocytes and DCs, increased Bcl-xL, blocked apoptosis, and improved survival. Anti-PD-1 also prevented the loss in DTH, a key indicator of immunocompetence in sepsis. Thus, delayed administration of anti-PD-1 antibody, an important therapeutic advantage, was effective in sepsis. Furthermore, these results add to the growing body of evidence that modulation of the positive and negative costimulatory pathways on immune cells represents a viable therapeutic approach in reversing immunosuppression and improving sepsis survival.

PubMed Disclaimer

Figures

Figure 1

Figure 1

PD‐1 expression temporally increases in CD4+ and CD8+ T cells in sepsis. PD‐1 expression was measured in isolated splenocytes via flow cytometry at various time‐points. PD‐1 expression increases on splenic CD4 and CD8 T cells 2 days after sepsis when compared with sham and remains elevated at 4 and 7 days. Number of mice for sham, n = 5–12; CLP, n = 6–17 (*, P < 0.01; **, P < 0.001). Graphs are aggregates of multiple experiments.

Figure 2

Figure 2

PD‐1 expression increases in sepsis–flow cytometric detection. Mice underwent sham or CLP surgery, and PD‐1 expression on CD4 T cells was quantitated via flow cytometry 4 days later. The cells located in the upper‐right quadrant of each panel are CD4+ T cells that express PD‐1. Note, the increase in PD‐1 expression in CD4 T cells from septic versus sham mouse. Flow diagram representative of data expressed in Figure 1.

Figure 3

Figure 3

PD‐1 blockade prevents loss of viable splenic immune cells. Viable splenocyte subsets were quantitated 48 h after surgery in sham and septic mice that had been treated with anti‐PD‐1 antibody, isotype control antibody (Iso), or saline 24 h after surgery. Treatment with anti‐PD‐1 prevented the loss of total viable splenocytes as a result of sepsis when compared with mice treated with isotype controls. There was no difference in total viable splenocytes in septic mice treated with saline or isotype control antibody. Anti‐PD‐1 antibody also prevented the loss in absolute cell counts for CD4 T, CD8 T, B, and NK cells and DCs when compared with mice treated with isotype control antibody. Each panel is an aggregate of two to three experiments; sham, n = 10; CLP + saline, n = 16; CLP + anti‐PD‐1, n = 7; CLP + isotype control antibody, n = 7; *, P < 0.01, for sham versus CLP + saline; **, P < 0.01, for CLP + saline versus CLP + anti‐PD‐1; ***, P < 0.01, for CLP + anti‐PD‐1 versus CLP + isotype control.

Figure 4

Figure 4

PD‐1 blockade inhibits splenic T cell apoptosis. Mice underwent sham or CLP surgery and 24 h later, had administration of anti‐PD‐1 antibody, isotype control antibody, or saline. At 48 h after surgery, splenocytes were harvested. Apoptosis was quantitated by TUNEL or active caspase‐3. Compared with sham, CLP causes significant increases in apoptosis as evaluated by TUNEL and active caspase‐3, which was prevented by treatment with anti‐PD‐1 antibody. Each figure is an aggregate of two to three experiments; sham, n = 10; CLP (CLP + saline), n = 16; CLP + anti‐PD‐1, n = 7; isotype (CLP + isotope control antibody), n = 7; *, P < 0.01, for sham versus CLP + saline; **, P < 0.01, for CLP + saline versus CLP + anti‐PD‐1; ***, P < 0.01, for CLP + anti‐PD‐1 versus CLP + isotype control.

Figure 5

Figure 5

PD‐1 blockade prevents the sepsis‐induced loss in Bcl‐xL. Mice underwent sham or CLP surgery and 24 h later, had administration of anti‐PD‐1 antibody or isotype control antibody. At 48 h after surgery, splenocytes were harvested. Mice undergoing CLP have decreased intracellular Bcl‐xL (indicated by decreased MFI) in CD4 and CD8 T cells when compared with sham‐operated animals, which was prevented by treatment with anti‐PD‐1 antibody. *, P < 0.01, for sham versus CLP + saline; **, P < 0.01, for CLP + saline versus CLP + anti‐PD‐1; ***, P < 0.05, for CLP + anti‐PD‐1 versus CLP + isotype control. Sham, n = 2; CLP + saline, n = 4; CLP + anti‐PD‐1, n = 5; and CLP + isotype control, n = 5. Histogram overlays represent one mouse from each group and show that treatment with the anti‐PD‐1 antibody increases MFI of Bcl‐xL.

Figure 6

Figure 6

Anti‐PD‐1 prevents the sepsis‐induced loss in DTH. Mice underwent sham or CLP surgery, and selected groups were treated with anti‐PD‐1 at 24 h after surgery. Four days postsurgery, mice were sensitized with TNP, and 4 days after sensitization, mice had rechallenge with TNP (footpad injection). At 24 h after rechallenge, the degree of footpad swelling was quantitated versus PBS injection, which functioned as the negative control (neg. contr.). The footpad swelling in the foot injected with TNP is the positive control (pos. contr.). The footpad swelling response of CLP mice treated with anti‐PD‐1 (aPD‐1) and then injected with TNP was significantly greater than the footpad swelling in the CLP mice that were injected with TNP and that did not receive anti‐PD‐1; *, P < 0.05; n = 10–12 mice/group.

Figure 7

Figure 7

PD‐1 blockade improves survival in CLP. Mice underwent CLP and 24 h later, were injected with anti‐PD‐1 antibody, saline, or isotype control antibody. A second injection of the anti‐PD‐1 or isotype control antibody was administered at 48 h after surgery. Survival was recorded for 78 days. Mice treated with blocking antibodies to PD‐1 had an improved 7‐day survival (70.6%) compared with mice treated with saline (33.3%; P<.05) or the isotype control (28.6%; *, P<0.05).

Comment in

References

    1. Angus, D. C. , Linde‐Zwirble, W. T. , Lidicker, J. , Clermont, G. , Carcillo, J. , Pinsky, M. R. (2001) Epidemiology of severe sepsis in the United States. Crit. Care Med. 29, 1303–1310. -PubMed
    1. Monneret, G. , Venet, F. , Pachot, A. , Lepape, A. (2008) Monitoring immune dysfunctions in the septic patient: a new skin for the old ceremony. Mol. Med. 14, 64–78. -PMC -PubMed
    1. Adib‐Conquy, M. , Cavaillon, J. M. (2009) Compensatory anti‐inflammatory response syndrome. Thromb. Haemost. 101, 36–47. -PubMed
    1. Osuchowski, M. F. , Welch, K. , Siddiqui, J. , Remick, D. G. (2006) Circulating cytokine/inhibitor profiles reshape the understanding of the SIRS/CARS continuum in sepsis and predict mortality. J. Immunol. 177, 1967–1974. -PubMed
    1. Hotchkiss, R. S. , Karl, I. E. (2003) The pathophysiology and treatment of sepsis. N. Engl. J. Med. 348, 138–150. -PubMed

MeSH terms

Substances

LinkOut - more resources