title: Blockade of the negative co-stimulatory molecules PD-1 and CTLA-4 improves survival in primary and secondary fungal sepsis.
abstract: BACKGROUND
  Fungal sepsis is an increasingly common problem in intensive care unit patients.Mortality from fungal sepsis remains high despite antimicrobial therapy that is highly active against most fungal pathogens, a finding consistent with defective host immunity that is present in many patients with disseminated fungemia.One recently recognized immunologic defect that occurs in patients with sepsis is T cell "exhaustion" due to increased expression of programmed cell death -1 (PD-1).This study tested the ability of anti-PD-1 and anti-programmed cell death ligand -1 (anti-PD-L1) antagonistic antibodies to improve survival and reverse sepsis-induced immunosuppression in two mouse models of fungal sepsis.
  
  
  METHODS
  Fungal sepsis was induced in mice using two different models of infection, that is, primary fungal sepsis and secondary fungal sepsis occurring after sub-lethal cecal ligation and puncture (CLP).Anti-PD-1 and anti-PD-L1 were administered 24 to 48 h after fungal infection and effects on survival, interferon gamma production, and MHC II expression were examined.
  
  
  RESULTS
  Anti-PD-1 and anti-PD-L1 antibodies were highly effective at improving survival in primary and secondary fungal sepsis.Both antibodies reversed sepsis-induced suppression of interferon gamma and increased expression of MHC II on antigen presenting cells.Blockade of cytotoxic T-lymphocyte antigen-4 (CTLA-4), a second negative co-stimulatory molecule that is up-regulated in sepsis and acts like PD-1 to suppress T cell function, also improved survival in fungal sepsis.
  
  
  CONCLUSIONS
  Immuno-adjuvant therapy with anti-PD-1, anti-PD-L1 and anti-CTLA-4 antibodies reverse sepsis-induced immunosuppression and improve survival in fungal sepsis.The present results are consistent with previous studies showing that blockade of PD-1 and CTLA-4 improves survival in bacterial sepsis.Thus, immuno-adjuvant therapy represents a novel approach to sepsis and may have broad applicability in the disorder.Given the relative safety of anti-PD-1 antibody in cancer clinical trials to date, therapy with anti-PD-1 in patients with life-threatening sepsis who have demonstrable immunosuppression should be strongly considered.
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Chang
authors.forename: Carey-Ann
authors.initials: CA
authors.lastname: Burnham
authors.forename: Stephanie M
authors.initials: SM
authors.lastname: Compton
authors.forename: David P
authors.initials: DP
authors.lastname: Rasche
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Mazuski
authors.forename: Jacquelyn S
authors.initials: JS
authors.lastname: McDonough
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Unsinger
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Korman
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Green
authors.forename: Richard S
authors.initials: RS
authors.lastname: Hotchkiss
mesh_terms: D000818:Animals; D000906:Antibodies / Q000627:therapeutic use*; D060890:B7-H1 Antigen / Q000037:antagonists & inhibitors* / Q000276:immunology; D060908:CTLA-4 Antigen / Q000037:antagonists & inhibitors* / Q000276:immunology; D002177:Candidiasis / Q000276:immunology / Q000628:therapy; D004195:Disease Models, Animal; D016469:Fungemia / Q000276:immunology* / Q000628:therapy*; D005805:Genes, MHC Class I; D006684:HLA-DR Antigens / Q000096:biosynthesis; D016867:Immunocompromised Host; D007371:Interferon-gamma / Q000096:biosynthesis; D008297:Male; D008810:Mice, Inbred C57BL; D061026:Programmed Cell Death 1 Receptor / Q000037:antagonists & inhibitors* / Q000276:immunology; D016019:Survival Analysis
chemical_list: D000906:Antibodies; D060890:B7-H1 Antigen; D060908:CTLA-4 Antigen; C498919:Cd274 protein, mouse; D006684:HLA-DR Antigens; D061026:Programmed Cell Death 1 Receptor; D007371:Interferon-gamma