GZMB+ B cells, a key factor of cell immunity in human?

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HAL Id: inserm-02164324

https://www.hal.inserm.fr/inserm-02164324

Submitted on 25 Jun 2019

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GZMB+ B cells, a key factor of cell immunity in human?

Mélanie Chesneau, Sabine Le Bot, Cyrielle Poulaouec, Richard Danger, Florian Dubois, Maxim Durand, Lola Jacquemont, Pierrick Guerrif, Nicolas

Degauque, Magali Giral, et al.

To cite this version:

Mélanie Chesneau, Sabine Le Bot, Cyrielle Poulaouec, Richard Danger, Florian Dubois, et al.. GZMB+ B cells, a key factor of cell immunity in human?. 3rd Igo meeting, Apr 2018, Nantes, France. �inserm-02164324�

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Chesneau Mélanie 1, 2, Le Bot Sabine 1, 2,3, Poulaouec Cyrielle 1, 2,3_, Danger Richard 1,2, Dubois Florian 1,2,3 Maxim Durand 1,2,3, Lola Jacquemont1, 2, 3, Guerrif Pierrick1,2,4 _{, Nicolas Degauque} 1, 2, 3_{, Giral Magali}1, 2, 3, 4_{, Brouard Sophie} 1, 2, 3, 4

1 _{Centre de Recherche en Transplantation et Immunologie UMR 1064, INSERM, Université de Nantes, Nantes, France.}2 _{Institut de Transplantation Urologie Néphrologie (ITUN), CHU Nantes, Nantes,}

France.3 _{Université de Nantes, UMR1064, Nantes, F-44000 France.}4 _{CIC Biotherapy, CHU Nantes, 30 bd Jean-Monnet, 44093 Nantes, France.}

GZMB

+

B cells, a key factor of cell immunity in human?

1-INTRODUCTION

Accumulating evidences show the existence of B-cells able to exert suppressing activities (Bregs) through different mechanisms. We

report on an increase of a specific B cell population with suppressive regulatory functions in the blood of transplanted patients with long-term graft outcome.

These B cells inhibit an effector T cell response through a granzyme B (GZMB+) dependent mechanism. We showed that such a population is present in healthy volunteer likely participating to a complex

homeostasis cell orchestra and key regulator of immune response in chronic inflammation.

The aim of our study is to characterize their phenotype, their mode of action and we propose a method to induced them for future cell therapy.

2-MATERIAL AND METHODS

PBMCs from Heathy volunteers => B cells isolation (negative selection) -GZMB+ B cells induction

-Analysis of regulatory function

3- RESULTS

4-CONCLUSION

1- In vitro GZMB

+

B cells induction

0 10 20 30 40 * *** GZ M B + B c e ll s ( % ) 0 200 400 600 800 1000 *** ** *** M F I o f GZ M B CD40L - + + ODN - + + Fab’2 - - + IL-21 - - + IL-2 - - + CD40L - + + ODN - + + Fab’2 - - + IL-21 - - + IL-2 - - +

2- Regulatory function of induced GZMB

+

B cells

LT Naive T cells (CD4+ CD25-) CD3 CD28 activation Ratio 2:1 72H co-culture CD40L CpG/ODN 24H IL-2 IL-21 Fab(’2) 0 20 40 60 T cells GZMB_i B cells B cells GZMB inhibitor + -+ -+ -+ -+ + + + -+ + -+ * In h ib it io n o f C D 4 + C D 2 5 -T c e ll p ro li fe ra ti o n ( % ) -60 -40 -20 0 20 40 60 T cells GZMB_i B cells TW + -+ + -+ -+ + + + * * In h ib it io n o f C D 4 + C D 2 5 -T c e ll p ro li fe ra ti o n ( % ) -100 0 100 200 ** Tcells B cells GZMB_i B cells GZMBinhibitor + -+ + -+ -+ -+ -+ + % i n d u c ti o n o f CD 1 2 7 - F OX P 3 + T c e lls

We identified Breg cells with a dual regulatory role, both blocking conventional T cell proliferation and inducting Treg cells but also maintaining cell homeostasis. These data evidence that GZMB+ B cells are tightly regulated through a feed back loop control of proliferation and death suggesting a fine control of these cells able to maintain a

physiological T cell response in healthy volunteers .

We identified an efficient induction protocol for Bregs with stable suppressive activity. These data provide new insights into the GZMB+ _{B cell biology and function as well as}

new clues for novel future therapies in inflammatory diseases and cancers. Around 17 % of GZMB+ B cells were induced (GZMB+_i

B cells) after 3 days culture with CD40L, ODN, Fab’2, IL-21 and IL-2.

GZMB+_i B cells inhibits effector T cells proliferation higher than non induced GZMB+ B cells in GZMB and contact dependent manner, without inducing T cells apoptosis.

After coculture with effector T cells, GZMB+_i B cells induces T cells with regulatory function in a GZMB dependent manner.

3- Homeostasis of GZMB

+

B cells

0 20 40 60 _* * GZMB_i B cells GZMB inhibitor + -+ -+ + + + GZMB+_i B cells GZMB- B cells p ro li fe ra ti n g B c e ll s ( % ) 0 20 40 60 GZMBi B cells GZMB inhibitor + -+ + + -+ + * * GZMB+_i B cells GZMB- B cells c a s p a s e 3 + B c e lls ( % )

Addition of GZMB inhibitor in 3 days culture prevents B cell proliferation suggesting that GZMB secreted by GZMB+

i B cells

concurs to their own proliferation.

GZMB+

i B cells are significantly more sensitive to apoptosis

compared to GZMB-_i B cells. -20 -10 0 10 20 Tcells B cells GZMB_i B cells + -+ + -+ -+ % o f CD1 2 7 + F O X P 3 + T c e ll s e x p e n s s io n 0 10 20 30 T cells GZMB_i B cells B cells GZMB inhibitor + -+ -+ -+ -+ + + + -+ + -+ % o f A n n e x in V + T c e ll s