The Basoph8 Mice Enable an Unbiased Detection and a Conditional Depletion of Basophils

Abstract

Basophils are granulocytes involved in parasite immunity and allergic diseases, known for their potent secretion of type 2 cytokines. Identifying their functions has proven to be controversial due to their relative rarity and their complex lineage phenotype. Here, we show that the expression of basophils lineage markers CD200R3 and FcεRIα is highly variable in inflammatory settings and hinders basophils identification by flow cytometry across multiple disease states or tissues. Fluorophore-conjugated antibody staining of these lineage markers strongly activates basophil type 2 cytokine expression, and represents a potential bias for coculture or in vivo transfer experiments. The Basoph8 is a mouse model where basophils specifically express a strong fluorescent reporter and the Cre recombinase. Basophils can be identified and FACS sorted unambiguously by their expression of the enhanced yellow fluorescent protein (eYFP) in these mice. We show that the expression of the eYFP is robust in vivo during inflammation, and in vitro on living basophils for at least 72 h, including during the induction of anaphylactoid degranulation. We bred and characterized the Basoph8xiDTR mice, in which basophils specifically express eYFP and the simian diphtheria toxin receptor (DTR). This model enables basophils conditional depletion relatively specifically ex vivo and in vivo during allergic inflammation and their detection as eYFP+ cells. In conclusion, we report underappreciated benefits of the commercially available Basoph8 mice to study basophils function.

The Gastrointestinal Helminth Heligmosomoides bakeri Suppresses Inflammation in a Model of Contact Hypersensitivity

“…Interestingly, one paper investigating different types of allergic response found that contact hypersensitivity with a chemical hapten was not affected by depletion of basophils (64), whereas another found a significant attenuation of ear swelling after hapten application in basophil depleted mice (66). Although we did not assess mast cell or basophil recruitment in our current model, previous work from our group has shown, using the Basoph-8 reporter mice (67), that basophils are recruited to the skin after injection with the allergen HDM and after prolonged topical application of a vitamin D analog MC903 that induces AD-like skin inflammation (68), and these mice could be utilized in the future to further understand the role of basophils in the Hb/DBP-FITC model. Indeed, studies in both mice and humans have implicated that helminth infection can reduce the responsiveness of basophils to IgE (69,70).…”

Panel Design and Optimization for High‐Dimensional Immunophenotyping Assays Using Spectral Flow Cytometry

“…The aim was to understand which cell types express IL‐4 and IL‐13 in the skin in a MC903‐induced atopic dermatitis model using triple‐reporter Basoph8 × 4C13R mice (Pellefigues et al., 2019). These mice express eYFP as a specific marker for basophils and report expression of the type 2 cytokines IL‐4 and IL‐13 as AmCyan and dsRed, respectively.…”

Is There a Role for Basophils in Cancer?

“…Many phenotypic markers have been identified on human and mouse basophils, with some minor differences worth noting. For example, basophils from both species express of a variety of activation-linked markers, namely FcεRI ( 33 , 34 ), but also the degranulation marker, CD63 ( 35 – 37 ), as well as CD203c –an ecto-nucleotide pyrophosphatase/phosphodiesterase ( 15 , 36 , 38 , 39 ). In contrast, human basophils express the IgG receptors FcγRIIA, FcγRIIB, and minute amounts of FcγRIIIB, whereas mouse basophils express FcγRIIB and FcγRIIIA ( 40 , 41 ).…”

“… ND, not done . a Several key surface markers are used to characterize human [IgE + , FcεRI + , CCR3 + , (CD123)IL-3Rα + , CD63 + , CD203c + ] ( 15 , 36 , 57 , 61 , 71 ) and murine basophils (FcεRI + , KIT − , CD49b + , CD200R3 + ) ( 35 , 62 , 72 – 76 ) by flow cytometric analysis . b This table essentially includes the phenotypic characteristics of peripheral blood human and mouse basophils.…”