Rosenmontag -Seminar

MHH, SeminarroomMHH, Seminarroom

15.02.201014.30h

Antigen + Basophils + CD4+ T cells TH2 cellsIL-4FcRI

MHC II

• representing less than 1% of circulating white blood cells

• susceptible to staining by base dyes

• Basophils appear in many specific kinds of inflammatory reactions

• can be found in unusually high numbers at sites of ectoparasite infection (e.g. ticks)

• basophils are primary effector cells in allergic disorders

Basophils

Splenic Basophils in Strongyloides venezuelensis infected mice

Higher percentages of Basophils in Strongyloides venezuelensis infected miceBaophils (0.2% naive, 5.84% inf.)Mastcells (0.02%naive, 0.39% inf.)

FcRI+ c-Kit - = Basophils

FcRI+ c-Kit + = Mast cells

Strongyloides venezuelensis

Cytokine production of Basophils after Strongyloides infection in vitro

Basophils from infected mice produce large amounts of „TH2 cytokines“

Basophils + IL-3 (24h)

Same amount of MHCII expression on Basophils of naive and infected mice=MHCII expression is no limiting factor for TH2 induction

MHC II expression on Basophils

Ability of basophils to induce naive CD4+ T cells to develop into TH2 cells

without IL4

without IL4

with IL4

Ability of basophils to induce naive CD4+ T cells to develop into TH2 cells

Basophils from infected mice are able to induce TH2 development without IL4

without IL4

with IL4

Ability of basophils to induce naive CD4+ T cells to develop into TH2 cells

Bone marrow basophils induce TH2 cells in vitro

Expression of MHC II and costimulatory molecules

Bone marrow basophils express MHCII, CD80, CD86

of IL4-/- mice (G4/G4)Basophils of wt mice

Basophils of wt mice are able to induce naive CD4+ cells to develop into TH2 cellsBasophils produce sufficient IL-4 for maximum development of TH2 cells

Bone marrow basophils induce TH2 cells in vitro

without IL4

with IL4

Basophils pulsed with antigen-IgE complexes are potent APCs

Basophils + DNP-OVA + CD4+ T cells TH2 cells

Basophils are able to process DNP-OVA into OVA(323–339) and to display peptide fragment in association with MHC class II and to produce IL-4

The enhancing effect of IgE anti-DNP on basophil-induced TH2 cell development was most apparent when basophils were pulsed with low concentrations of DNP-OVA

Basophils + DNP-OVA + IgE anti DNP + CD4+ T cells TH2 cells

-

+

CD4+ T cells + OVA or DNP-OVA +/- IgE anti-DNP

These results suggest that basophils, taking advantage of their expression of FcRI, might efficiently take up low doses of antigen in an IgE-dependent way

of

DNP-OVA

Proliferation assay of CD4+ T cells

APC activity of basophils and sorted CD11c+ splenic DCs by changing the ratio of APCs to naive CD4+ T cells

In presence of IgE-complex even low ratios of basophils induce TH2 development

in vitro in vivo

Basophils are able to induce naive CD4+ cells to develop into

TH2 cells in vitro

OVA-pulsed basophils induce TH2 cells in vivo

Basophils + DNP-OVA + IgE anti DNP mice + challenge with OVA

CD4+ T cells + OVA-pulsed T–spleen cells

Basophils induce TH2 development in vivo

OVA-pulsed basophils induce TH2 cells in vivo

Basophils + DNP-OVA + IgE anti DNP mice + challenge with OVA

CD4+ T cells + OVA-pulsed T–spleen cells

Basophils induce TH2 development in vivo

DCs induce TH1 but not TH2 development in vivo

OVA-pulsed basophils induce TH2 cells in vivo

Does OVA-pulsed basophils induce IgE and IgG1 production?

OVA-pulsed basophils induce IgE and IgG1 production

Basophils are important to induce TH2 responses in vivo

Basophils + OVA mice

Intravenous administration of antigen-IgE complex induces TH2 responses

IC = Immune Complex (DNP-OVA + IgE anti DNP)MAR-1 = anti-FcRI

Basophils efficiently take up IC and induce TH2 development in vivo

Depletion of Basophils blocks TH2 development and therefore IgG1 production of B cells

What happens aftre depletion of basophils?

Intravenous administration of antigen-IgE complex induces TH2 responses

Does IL-3 administration increases the number of basophils?

Higher numbers of basophils lead to increased production of IgE and IgG1

Yes, it does!

Influence on Antibody production?

Summary

Basophils produce large amounts of „TH2 cytokines“ IL-4 and IL-13 after uptake of antigen

Basophils are potent APCs

Basophils are able to induce naive CD4+ cells to develop into TH2 cells

Intravenous administration of antigen-IgE complex induces TH2 responses in vivo

Antigen + Basophils + CD4+ T cells TH2 cellsIL-4FcRI

MHC II

Thank you for your attention!