CHARACTERIZATION OF EXTRAFOLLICULAR PLASMABLAST RESPONSE IN TRYPANOSOMA CRUZI INFECTION.

ALMADA, LAURA; BECCARIA, CRISTIAN G; MONTES, CAROLINA L.; GAZZONI, YAMILA; GOROSITO SERRAN, MELISA; ACOSTA RODRIGUEZ E V; FIOCCA VERNENGO, FACUNDO; BOCCARDO, SANTIAGO; GRUPPI, ADRIANA

Fairmont Banff Springs, Banff, AB, Canada

Simposio; Keystone Symposia: T Cell Memory joint with B Cell Renaissance: Epigenetics, Regulation and Immunotherapy.; 2020

Keystone symposia

CHARACTERIZATION OF EXTRAFOLLICULAR PLASMABLAST RESPONSE INTRYPANOSOMA CRUZI INFECTIONAlmada L 1 , Gazzoni Y 1 , Fiocca Vernengo F 1 , Beccaria CG 1 , Boccardo S 1 , Gorosito SerranM, Bossio S, Montes CL 1 , Acosta-Rodriguez EV 1 , Gruppi A 1 .1 Centre for Research in Clinical Biochemistry and Immunology (CIBICI)-CONICET,FCQ-Universidad Nacional de Córdoba, Argentina.B cells are the unique population able to differentiate into antibody-secreting-cells (ASC).The Germinal Center reaction-GC- and the extrafollicular-EF- response generate differenttypes of ASC which provide long- and short-term humoral immunity against infections,respectively. The participation of follicular T helper cells -Tfh-, is key in these processes. Inour lab, we identified a population of EF-ASC (B220 int CD138+ Blimp-1+, Plasmablasts/PB)characterized by high expression of PD-L1 and CD39, only present in murine infectionmodels but not in autoimmunity or in immunizations. In the infections, these PB have thecapability to modulate the T-cell response, since chimera models lacking PD-L1 hi PB havean increase in TNF-IFNγ-producing PD-1+CD4+ T cells. The aim of our work is tocharacterize the phenotype of regulatory PB and the mediators involved in theirinduction/survival. Therefore, B6 mice were infected with T. cruzi and splenic, lymph node(LN) and bone marrow (BM) lymphocytes were evaluated by FACS at different days postinfection (dpi). In the spleen, the peaks of frequency of PB and GC Bcells (Fas+GL7+) weredetected at 18 and 28dpi, respectively; while in the LN the peak of PB was detected at23dpi. The 99% of splenic PB expressed high levels of PD-L1 and CD39 until day 23pi andthis frequency was significantly reduced from day 28pi (p