An edit that requires some reorganization

Posted on by Occam's Bible

Below are three versions of a 2007 article from the “American Journal of Transplantation.” The first entry is the original language, the second shows my editing, (my additions underlined and words I’m removing or moving have a line through them), and the third is the product I would submit for approval.

 

Original Language

A Mouse Model of Orthotopic Vascularized Aerated Lung Transplantation

OkazakiA. S. KrupnickC. G. Kornfeld J. M. Lai J. H. Ritter S. B. Richardson H. J. Huang N. A. Das G. A. Patterson A. E. Gelman D. Kreisel

American Journal of Transplantation Volume7, Issue6 June 2007 Pages 1672-1679

Lung transplantation represents a highly successful therapy for patients with end‐stage lung diseases. Nevertheless, compared with other types of solid‐organ transplants, the survival rate of lung transplantation is one of the lowest: 50% of patients will lose their graft 5 years after transplantation. A technically challenging mouse model of orthotopic lung transplant has been helpful in unveiling the singularity of the immune response during the course of a lung transplant.1 Such models have demonstrated the intragraft infiltration observed in transbronchial biopsies from lung transplant recipients experiencing acute rejection.1 The immune response that leads to graft rejection in lung transplant recipients presents unique features compared with other organ transplants. The group of D. Kreisel has previously shown that alloreactive T cells are primed within lung allografts and not in secondary lymphoid organs.2 More recently, they have demonstrated that the acceptance of a lung allograft depends on rapid graft infiltration by central memory (CM) CD8 T cells.3 Stable synapses between CM CD8 and antigen‐presenting cells are needed to establish a local pro‐tolerogenic environment. The positive role of CM CD8 in the lung allograft is paradoxical as preexisting memory cells are recognized as a major hurdle to achieve long‐term graft acceptance for other solid organ transplants. In this issue of the American Journal of Transplantation, Takahashi and colleagues further defined the mechanisms leading to lung transplant acceptance and assessed the involvement of the PD‐1/PD‐L1 pathway.4 They first demonstrated, in a fully allogeneic mismatch model of orthotopic lung transplantation, that 2 injections of anti‐PD‐1 on day ‐2 and day 2 disrupt tolerance induced by costimulatory blockade. Rejection was associated with a shift in the phenotype of graft‐infiltrating CD8 T cells from CM to effector memory (EM). Of interest, the expansion of EM CD8 could not be observed in graft‐draining lymph nodes or the spleen: observations that further emphasize the unique complexity of the immune response in lung allotransplantation. The critical role of PD‐1 expression by CD8 T cells was then demonstrated using C57BL/6 PD‐1−/− recipients that acutely rejected lung allografts compared with wild‐type (WT) recipients. Congenic CD45.2 CD8 T cells purified from WT or PD‐1‐deficient mice were then transferred into a CD45.1 host that had been grafted with BALB/C lung and treated with costimulatory blockade. The adoptive transfer of PD‐1−/− CD8 T cells resulted in severe acute rejection and graft infiltration by EM CD8 with higher rates of proliferation. Takahashi et al then used intravital 2‐photon microscopy to evaluate how PD‐1 regulates the interaction between CD8 T cells and CD11c within lung allografts. Fluorescent‐labeled CD8 T cells isolated from B6 WT or PD‐1‐deficient mice were injected into the immunosuppressed B6 CD11c‐EFYP recipient. The inability to engage the PD‐1 pathway resulted in a prolonged interaction between CD8 T cells and CD11c+ antigen‐presenting cells. Finally, Takahashi et al demonstrated that the engagement of the PD‐1 pathway inhibited the accumulation of CD8 T cells within the lungs by transferring equal numbers of WT and PD‐1−/− CD8 into C57BL/6 recipients of BALB/C lung. Collectively, the authors demonstrate that tolerance is dependent on PD‐1 expression in CD8 T cells. The PD‐1/PDL1 interaction between CM CD8 T cells and CD11c+ cells, respectively, prevents the differentiation of CD8 T cells into an EM phenotype and consequently contributes to allograft acceptance.

Therefore, the local environment within the lung allograft finely tunes the alloimmune response. A delicate balance in the length of the interaction between CD8 CM and CD11c has to be achieved. CM CD8 needs a sustained interaction with CD11c through the CCR7‐CCL21 pathway to induce iNOS secretion. Nevertheless, if the interaction is long lasting, CM CD8 will differentiate into effector CD8, as evidenced by the loss of CCR7, and the lung allograft will be rejected. The article by Takahashi et al provides evidence that PD1‐PDL1 plays a key role in achieving an appropriate interaction time. Nevertheless, because the interaction between CM CD8 and antigen‐presenting cells is critical to achieve transplant tolerance, it is likely that other mechanisms that remained to be identified govern the fine‐tuning of the interaction time between CCR7‐expressing CM CD8 and CCL21‐expressing antigen‐presenting cells.

The tolerance protocol used by Takahashi et al based on costimulatory blockade and tolerance depends on CD8, but not CD4, T cells. Other protocols aiming to induce mixed hematopoietic chimerism in nonhuman primates5 or in miniature swine6 have shown that lymphodepletion of CD8 T cells was needed to induce prolonged graft acceptance. Using an immunosuppressive regimen with low‐dose irradiation and donor‐specific splenocyte infusion, tolerance to fully allogeneic lung transplant can be achieved in miniature swine.6Recipients with a stable allograft exhibit a marked increase in CD4 TREG cells in the blood and bronchoalveolar lavage. Additionally, long‐lasting depletion of effector CD8 T cells was observed in the periphery, but tests to determine the nature of lung‐infiltrating CD8 T cells in the tolerant animals were not performed. After the profound lymphodepletion induced by whole‐body irradiation, it would be of great interest to characterize the phenotype of newly generated CD8 T cells and to assess whether CM CD8 T cells infiltrate lung allografts in tolerant recipients. Such study could therefore extend the findings observed in the rodent animal model used by Takahashi and colleagues. Nevertheless, it is likely that the contribution of CM CD8 to lung allograft acceptance is influenced by the immunosuppressive regimen. Whether infiltration and expansion of CM CD8 in the lung occurs in humans remains to be established. A side‐by‐side investigation of the immune compartment in the blood and in the bronchoalveolar lavage of lung transplant recipients undergoing acute rejection will be interesting to pave the road toward translating the findings to humans. Manipulating the immune system locally and tailoring therapies according to the nature of the graft may improve the outcome of human lung transplantation.

 First Mark-Up

Lung transplantation represents is a highly successful therapy for patients with end‐stage lung diseases. Nevertheless, compared with to other types of solid‐organ transplants, however, the survival rate of lung transplantation is one of the lowest: with only 50% of patients will lose retaining  their graft 5 years after transplantation. A technically challenging mouse model of orthotopic lung transplant has been helpful in unveiling revealing (there is no veil) the singularity (singularity is a term in physics) of the immune response during the course of a lung transplant.1 Such models have demonstrated [[the intragraft infiltration observed in transbronchial biopsies from lung transplant recipients experiencing acute rejection]] (incomplete fragment).1 The immune response that leads to graft rejection in lung transplant recipients presents unique features compared with to other organ transplants. The group of D. Kreisel has previously shown that alloreactive T cells are primed within lung allografts and but not in secondary lymphoid organs.2 More recently, they have demonstrated that the acceptance of a lung allograft depends on rapid graft infiltration by central memory (CM) CD8 T cells.3 Stable synapses between these CM CD8 and antigen‐presenting cells are needed to establish a local pro‐tolerogenic environment. The positive role of CM CD8 in the lung allograft is paradoxical as because preexisting memory cells are recognized as a major hurdle to achieveing long‐term graft acceptance for in other solid organ transplants. ¶ In this issue of the American Journal of Transplantation, Takahashi and colleagues further defined the mechanisms leading to lung transplant acceptance and by assessed assessing the involvement of the PD‐1/PD‐L1 Pathway.4 They first demonstrated that 2 injections of anti‐PD‐1 (on transplant day ‐2 and day +2), disrupt tolerance usually induced by costimulatory blockade, in using a fully allogeneic mismatch model of orthotopic lung transplantation, that 2 injections of anti‐PD‐1 on day ‐2 and day 2 disrupt tolerance induced by costimulatory blockade. Rejection Failure of tolerance was associated with a shift in the phenotype of graft‐infiltrating CD8 T cells from a CM phenotype to an effector memory (EM) phenotype. Of interest, the Strangely though, expansion of EM CD8 could not be observed in graft‐draining lymph nodes or in the spleen,:observations that further emphasize the unique complexity of differentiate the immune response in lung allotransplantation as opposed to (other solidorgan transplants?). The critical role of PD‐1 expression by CD8 T cells was then demonstrated using by comparing C57BL/6 PD‐1−/− recipients,(that acutely rejected lung allografts) compared with to wildtype (WT) recipients. Congenic CD45.2 CD8 T cells purified from WT or PD‐1‐deficient mice were then transferred into a CD45.1 hosts that had been grafted with BALB/C lung and treated with costimulatory blockade. The adoptive transfer of PD‐1−/− CD8 T cells resulted in severe acute rejection and graft infiltration by EM CD8 [with higher rates of proliferation] of what?. Takahashi et al thenused intravital 2‐photon microscopy was then used to evaluate how PD‐1 regulates the interaction between CD8 T cells and CD11c within lung allografts. Fluorescent‐labeled CD8 T cells isolated from B6 WT or PD‐1‐deficient mice were injected into the immunosuppressed B6 CD11c‐EFYP recipients. The inability Cells from PD-1-deficient mice failed to engage the PD‐1 pathway and resulted in a prolonged interaction between CD8 T cells and CD11c+ antigen‐presenting cells. Finally, by transferring equal numbers of WT and PD‐1−/− CD8 into C57BL/6 recipients of BALB/C lungs,Takahashi et al demonstrated that the engagement of the PD‐1 pathway inhibited the accumulation of CD8 T cells within the lungs by transferring equal numbers of WT and PD‐1−/− CD8 into C57BL/6 recipients of BALB/C lung. Collectively, the authors demonstrate that tolerance is dependent on PD‐1 expression in CD8 T cells. The PD‐1/PDL1 interaction between CM CD8 T cells and CD11c+ cells, respectively, prevents the differentiation of CD8 T cells into an EM phenotype and consequently contributes to allograft acceptance.

Therefore, the local environment within the lung allograft finely tunes the alloimmune response. A delicate balance in the length of the interaction between CD8 CM and CD11c has to be achieved. CM CD8 cells needs a sustained interaction with CD11c through the CCR7‐CCL21 pathway to induce iNOS secretion. Nevertheless, , but if the interaction is too long lasting, CM CD8 cells will differentiate into effector CD8, as evidenced by the loss of CCR7, and the lung allograft will be rejected. The article by Takahashi et al provides evidence that PD1‐PDL1 interaction plays a key role in achieving an appropriate interaction time. Nevertheless, because the interaction between CM CD8 and antigen presenting cells is critical to achieve transplant tolerance, it is likely that other mechanisms are necessary for fine‐tuning of the interaction time between CCR7‐expressing CM CD8 T cells and CCL21‐expressing antigen‐presenting cells. These potential Mechanisms that remained to be identified. govern the fine‐tuning of the interaction time between CCR7‐expressing CM CD8 and CCL21‐expressing antigen‐presenting cells.

The tolerance protocol used by Takahashi et al based on costimulatory blockade and tolerance depends on CD8, but not CD4, T cells (The meaning of this sentence can’t be determined “The protocol depends on cells.”). Other protocols aiming intended to induce mixed hematopoietic chimerism in nonhuman primates5 or in miniature swine6 have shown that lymphodepletion of CD8 T cells was is needed to induce prolonged graft acceptance. By uUsing an immunosuppressive regimen with low‐dose irradiation and donor‐specific splenocyte infusion, tolerance to fully allogeneic lung transplant can be achieved in miniature swine.6 Recipients with a stable allograft exhibit a marked increase in CD4 TREG cells in the blood and bronchoalveolar lavage. Additionally, long‐lasting depletion of effector CD8 T cells was observed in the periphery, but tests to determine the nature of lung‐infiltrating CD8 T cells in the tolerant animals were not performed.  After the profound lymphodepletion induced by whole‐body irradiation, it would be of great interest to characterize the phenotype of the newly generated CD8 T cells observed after lymphodepletion, and to assess whether CM CD8 T cells infiltrate lung allografts in tolerant recipients. Such study could therefore extend the findings observed in the rodent animal model used by Takahashi and colleagues. Nevertheless? ¶ A side‐by‐side comparison of the immune compartment in the blood vs. the bronchoalveolar lavage of lung transplant recipients undergoing acute rejection will be a necessary step in the process of translating the findings to humans., From these newly published results it is  appears likely that the contribution of CM CD8 T cells to lung allograft acceptance is influenced by the immunosuppressive regimen. Whether infiltration and expansion of CM CD8 in the lung occurs in humans remains to be established. A side‐by‐side investigation of the immune compartment in the blood and in the bronchoalveolar lavage of lung transplant recipients undergoing acute rejection will be interesting to pave the road toward translating the findings to humans. Manipulating the immune system locally and tailoring therapies according to the nature of the graft may improve the outcome of human lung transplantation.

First Edit Submission

Lung transplantation is a highly successful therapy for patients with end‐stage lung diseases. Compared to other types of solid‐organ transplants, however, the survival rate of lung transplantation is one of the lowest with only 50% of patients retaining their graft after five years. Graft rejection in lung transplant recipients presents unique features compared to other organ transplants, especially in the recipient’s immune response. The intricacies of the immune response during the course of a lung transplant has been newly investigated using a mouse model of orthotopic lung transplant.1

Kreisel et al. have previously shown that alloreactive T cells are primed (short explanation) within lung allografts but not in secondary lymphoid organs (do you mean lymphoid organ transplants?).2 More recently, they demonstrated that the acceptance of a lung allograft depends on rapid infiltration of the graft by CD8 Central Memory (CM) T cells (I thought CD8 is a modifier so I’m placing it ahead of “Central Memory,” but please correct if wrong).3  These T cells must make synapses with antigen‐presenting cells in order to to establish a local protolerogenic environment. The positive role of CD8 CM cells in the lung allograft is paradoxical because in other solid organ transplants preexisting memory cells are a major hurdle to achieving long‐term graft acceptance.

In this issue of the American Journal of Transplantation, Takahashi and colleagues further define the mechanisms leading to lung transplant acceptance by assessing the involvement of the Programmed Cell Death PD‐1/PD‐L1 pathway.4 Using a fully allogeneic mismatch model of orthotopic lung transplantation, they demonstrate that 2 injections of anti‐PD‐1 antibodies (on transplant days ‐2 and +2), disrupt tolerance usually induced by costimulatory blockade. Failure of tolerance was associated with a shift in the phenotype of graft‐infiltrating CD8 T cells from a CM phenotype to an Effector Memory (EM) phenotype. Expansion of EM CD8 cells was not evident in graft‐draining lymph nodes or in the spleen, observations that differentiate the immune response in lung allotransplantation (as opposed to other solid organ transplants?).

The critical role of PD‐1 expression by CD8 T cells was then queried by comparing C57BL/6 PD‐1−/− recipients, to wildtype (WT) allograft recipients. While the WT recipients retained their graft, PD-1 -/- recipients strongly rejected it. Next, congenic CD45.2 CD8 T cells purified from WT or PD‐1‐deficient mice were transferred into CD45.1 hosts that had been grafted with BALB/C lung and treated with costimulatory blockade. The transfer of PD‐1−/− CD8 T cells resulted in severe acute rejection and graft infiltration by EM CD8 cells with higher rates of proliferation (of what?). Intravital 2‐photon microscopy was then used to evaluate how PD‐1 regulates the interaction between CD8 T cells and CD11c within lung allografts. Fluorescent‐labeled CD8 T cells isolated from B6 WT or PD‐1‐deficient mice were injected into immunosuppressed B6 CD11c‐EFYP recipients. The cells from PD-1-deficient mice failed to engage the PD‐1 pathway and resulted in a prolonged interaction between CD8 T cells and CD11c+ antigen‐presenting cells. Finally, by transferring equal numbers of WT and PD‐1−/− CD8 into C57BL/6 recipients of BALB/C lungs, Takahashi et al. demonstrated that the engagement of the PD‐1 pathway inhibited the accumulation of CD8 T cells within the lungs. The authors thereby demonstrate that lung graft tolerance is dependent on PD‐1 expression in CD8 T cells. The implication is that PD‐1/PDL1 interaction between CD8 CM T cells and CD11c+ cells, respectively, (not sure what “respectively” means here) prevents the differentiation of CD8 T cells into an EM phenotype and allowing allograft acceptance.

This article also provides evidence that PD1‐PDL1 interaction plays a key role in achieving an appropriate interaction time between CD8 CM and CD11c. CD8 CM cells need a sustained interaction with CD11c through the CCR7‐CCL21 pathway to induce iNOS secretion, (reference?), but if the interaction is too long-lasting, CD8 CM cells will differentiate into CD8 EM, (as evidenced by the loss of CCR7), and the lung allograft will be rejected. They also demonstrate that tolerance depends on (the presence of, activity of?) CD8, but not CD4, T cells.

Other authors have shown that lymphodepletion of CD8 T cells by an immunosuppressive regimen of low‐dose irradiation and donor‐specific splenocyte infusion allows tolerance to fully allogeneic lung transplant and prolonged graft acceptance in nonhuman primates,5 and miniature swine.6  This result appears to indicate that the contribution of CD8 CM T cells to lung allograft acceptance is influenced by the immunosuppressive regimen. While infiltration and expansion of CM CD8 T cells occurs in these model systems, it remains to be determined whether this process occurs in human lung recipients. Perhaps manipulating the immune system locally and tailoring therapies according to the nature of the graft will improve the outcome of human lung transplantation.