SIGNR1 resides in the spleen marginal zone 28 and lymph node medulla 34 captures antigens from distal infection sites via blood and lymph, respectively. Therefore, SIGNR1 in confined parts of the body in vivo plays a role as the first sensing machinery against infection. For instance,

it is known that SIGNR1 in the spleen marginal zone is involved in systemic complement activation by sensing blood-borne CPS of S. pneumoniae35. Likewise, rpMϕ are also the first interceptors for peritoneal infection and a major source of oxidative burst in peritoneal cells, as shown Fig. 4D, possibly leading to subsequent inflammatory responses in the cavity. The host innate immune system simultaneously recognizes various types of ligands on microbes via a variety of receptors on the various types selleck kinase inhibitor of cells. Recently, Dectin-2 36, 37 has been shown to also be important for host response to C. albicans. Nevertheless, our finding sheds light on the cooperation selleck screening library of different and/or similar types of PRRs in innate responses. Like the intracellular crosstalk of distinct PRR-mediated signaling pathways, PRRs also collaborate to recognize and capture

microbes and to transduce signals for enhancing cellular responses. Collectively, although the cooperative action pathway between SIGNR1 and Dectin-1 in the oxidative response is not entirely definitive, our results suggest that the anti-microbial activity/oxidative burst induction is due to efficient recognition of cell wall mannoproteins via SIGNR1 and their subsequent internalization, possibly along with the association with Dectin-1, allowing Dectin-1 to access the limited β-glucans and leading to the activation of Syk-mediated signaling. Female check details BALB/c mice were purchased from Japan SLC (Hamamatsu, Shizuoka, Japan). The mice were maintained under specific pathogen-free conditions, and used at 8–12 wk of age. All experiments were conducted according to our institutional guidelines. HEK293T cells, the mouse monocytic cell line RAW264.7 cells and RAW-transfectants (RAW-SIGNR1, RAW-control and RAW-SIGNR1Δcyto

cells) were maintained as described previously 26. Expression levels of SIGNR1 and Dectin-1 of these transfectants were analyzed with biotinylated anti-SIGNR1 clone 22D1 28 with PE-streptavidine and anti-Dectin-1 clone 2A11 (AbD Serotec, Oxford, UK) with PE-anti-rat IgG, respectively. Substitutions of glutamic acid 285 with glutamine (E285Q) in SIGNR1 were introduced by overlapping PCR. cDNA fragments of SIGNR1ΔCRD (192–325) was PCR amplified using forward primer 5′-GATCGAATTCATGAGTGACTCCACAGAAGCC-3′ in combination with reverse primer 5′-GATCCTCGAGCTACAGGCGGAAGAGTTCAGTCTTC-3′. pcDNA4/HisMax-SIGNR1 23 was used as a template, and the resulting PCR products were cloned into the EcoRI-XhoI site of pcDNA4/HisMax (Invitrogen, Carlsbad, CA). Surface expression of these mutant proteins was confirmed by flow cytometry with polyclonal anti-SIGNR1 (R&D Systems, Minneapolis, MN).