VIRUS SPECIFIC AND BYSTANDER-B CELL ACTIVATION ACCOUNT FOR THE MASSIVE PLASMABLAST RESPONSE DURING HUMAN HANTAVIRUS INFECTION

GARCIA MARINA; IGLESIAS A; LANDONI V.I; BELLOMO C,; BRUNO A,; CORDOBA; SASIAIN MC; MARTINEZ V; SCHIERLOH P

Ciudad Autónoma de Buenos Aires

Congreso; Reunión Científica Anual de la Sociedad Argentina de Inmunología.; 2015

Background: In a recent study, we described the presence of huge amounts of circulating plasmablast (PB) in Hantavirus Pulmonary Syndrome (HPS) patients infected with local Andes virus (ANDV) strains. This strong PB response was time dependent with peak values around one week after symptoms onset but it was unrelated with viremia, virus strains and immunoglobulin (Ig)M-specific serological status. Therefore, to better understand the origin of such reactive cellular response, herein we analyzed the immunoreactivity of PB circulating in ANDV+ patients. Methods: ANDV+ patients (n=18), healthy subjects (HS, n=12), influenza vaccinated HS (v-HS, n=12), acute respiratory subjects (ARS, n=15) and tuberculosis patients (TB, n=10) were enrolled and their blood samples were fixed (TranfixTM) for protein stabilization. Red blood cells were lysed and intracytoplasmatic antibodies (cyAb) from leucocytes were obtained by non-anionic detergent extraction. This new method was properly validated by comparing with the gold-standard functional assay (ELISPOT). CyAb were tested by indirect ELISA against ANDV specific antigens (Ags)/epitopes (n=4) and unrelated Ags (n=8). Results: As expected, only ANDV+ PB derived cyAb reacted with all 4 virus specific Ags (p