title: Cry1Ac protoxin from Bacillus thuringiensis promotes macrophage activation by upregulating CD80 and CD86 and by inducing IL-6, MCP-1 and TNF-α cytokines.
abstract: Bacillus thuringiensis Cry1Ac protoxin (pCry1Ac) is a promising mucosal adjuvant, but its action mechanism is unknown. We examined in vivo whether pCry1Ac promotes the activation of macrophages in the peritoneum, spleen and mesenteric lymph nodes or in the lungs and bronchoalveolar lavage after intraperitoneal or intranasal pCry1Ac administration, respectively, in BALB/c mice. pCry1Ac upregulated the costimulatory molecules CD80 and CD86 in these macrophages, but with distinct kinetics. In vitro stimulation of resident macrophages with pCry1Ac upregulated CD80 and CD86 and enhanced the production of the pro-inflammatory cytokines TNF-α, IL-6 and MCP-1. To investigate whether the pCry1Ac-induced activation was mediated through MAPK pathways, we pretreated RAW 264.7 cells with signaling inhibitors of MEK, JNK and p38 MAPKs (PD98059, SP600125 and SB203580, respectively). pCry1Ac-induced upregulation of CD86 and CD80 was partially inhibited by the MEK inhibitor. While LPS-induced upregulation mechanisms of CD80 and CD86 appear to be different; as these were particularly inhibited by MEK and JNK inhibitors, respectively. pCry1Ac-induced IL-6 and MCP-1 production was especially inhibited with the p38 MAPK inhibitor, whereas TNF-α was only slightly inhibited upon treatment with JNK and p38 MAPK inhibitors. Therefore macrophage stimulation with pCry1Ac induced the upregulation of CD80 and CD86, and the production of IL-6, TNF-α and MCP-1, possibly, through the MEK and p38 MAPK pathways. It also promoted the nuclear translocation of NF-κB p50 and p65, the upregulation of MHC-II, and the activation of T CD4+ cells. These results suggest that pCry1Ac induced macrophage activation through mechanisms which differ partially from the LPS-induced.
authors.affiliation: Laboratorio de Inmunidad en Mucosas, Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios 1, Los Reyes Iztacala, Tlalnepantla 54090, Estado de México, México. Electronic address: lemofi@unam.mx.
authors.forename: Leticia
authors.initials: L
authors.lastname: Moreno-Fierros
authors.forename: Ana Lilia
authors.initials: AL
authors.lastname: García-Hernández
authors.forename: Damaris
authors.initials: D
authors.lastname: Ilhuicatzi-Alvarado
authors.forename: Lucio
authors.initials: L
authors.lastname: Rivera-Santiago
authors.forename: Marilú
authors.initials: M
authors.lastname: Torres-Martínez
authors.forename: Néstor
authors.initials: N
authors.lastname: Rubio-Infante
authors.forename: Martha
authors.initials: M
authors.lastname: Legorreta-Herrera
mesh_terms: D000818:Animals; D018122:B7-1 Antigen / Q000378:metabolism*; D051940:B7-2 Antigen / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004731:Endotoxins / Q000494:pharmacology*; D005260:Female; D006460:Hemolysin Proteins / Q000494:pharmacology*; D008168:Lung / Q000166:cytology; D008198:Lymph Nodes / Q000166:cytology; D008262:Macrophage Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D052002:NF-kappa B p50 Subunit / Q000378:metabolism; D010537:Peritoneum / Q000166:cytology; D013154:Spleen / Q000166:cytology; D051996:Transcription Factor RelA / Q000378:metabolism
chemical_list: D018122:B7-1 Antigen; D051940:B7-2 Antigen; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; C497965:Cd86 protein, mouse; D016207:Cytokines; D004731:Endotoxins; D006460:Hemolysin Proteins; D052002:NF-kappa B p50 Subunit; D051996:Transcription Factor RelA; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D020928:Mitogen-Activated Protein Kinases
keywords: Cry1Ac protoxin; Macrophage activation; Mucosal adjuvant