BLT1 mediates commensal bacteria-dependent innate immune signals to enhance antigen-specific intestinal IgA responses

Abstract

Leukotriene B 4 receptor 1 (BLT1) triggers the migration of granulocytes and activated T cells; however, its role in B-cell function remains unclear. Here we report that BLT1 is required to induce the production of antigen-specific IgA against oral vaccine through mediating innate immune signals from commensal bacteria. B cells acquire BLT1 expression during their differentiation to IgA + B cells and plasma cells in Peyer's patches and the small intestinal lamina propria, respectively. BLT1 KO mice exhibited impaired production of antigen-specific fecal IgA to oral vaccine despite normal IgG responses to systemically immunized antigen. Expression of MyD88 was decreased in BLT1 KO gut B cells and consequently led to diminished proliferation of commensal bacteria-dependent plasma cells. These results indicate that BLT1 enhances the proliferation of commensal bacteria-dependent IgA + plasma cells through the induction of MyD88 and thereby plays a key role in the production of antigen-specific intestinal IgA.

Leukotriene B4 receptor BLT1 signaling is critical for neutrophil apoptosis and resolution of experimental Lyme arthritis

“…Flow cytometry of isolated inflammatory cells from the infected joints demonstrated BLT1 expression on neutrophils (Ly6G + ), macrophages (F480 + ), and B cells (B220 + ) (Figure A). This is in agreement with the previous reports of BLT1 expression in murine peripheral blood and in intestinal tissues following oral vaccination . BLT1 mRNA levels in ankle joints over time were determined using qRT‐PCR.…”

“…This is in agreement with the previous reports of BLT1 expression in murine peripheral blood 28 and in intestinal tissues following oral vaccination. 36 BLT1 mRNA levels in ankle joints over time were determined using qRT-PCR. Figure 1B shows the levels of BLT1 mRNA increased significantly in B. burgdorferi-infected ankle joints on days 7 and 10 postinfection before returning to baseline levels.…”

Lymphoid Tissue–Resident Alcaligenes Establish an Intracellular Symbiotic Environment by Creating a Unique Energy Shift in Dendritic Cells

“…Reverse transcription and quantitative PCR analysis was performed as previously described (Nagatake et al, 2019). Total RNA was isolated from BMDCs by using Sepazol (Nacalai Tesque) and chloroform (Nacalai Tesque), precipitated with 2-propanol (Nacalai Tesque), and washed with 75% (vol/vol) ethanol (Nacalai Tesque).…”

12-Hydroxyeicosapentaenoic acid inhibits foam cell formation and ameliorates high-fat diet-induced pathology of atherosclerosis in mice

“…Flow cytometry analysis was performed as reported with modifications 59 . Briefly, the upper side of the heart, containing aortic valve was isolated and cut into small pieces by using scissors and incubated for 30 min at 37 °C with stirring in RPMI1640 medium (Sigma-Aldrich) containing 2% (vol/vol) newborn calf serum (Equitech Bio) and 0.5 mg/mL collagenase (Wako Chemicals).…”