In vitro assay for quantitating secreted antibodies in lymphocyte supernatant for evaluation of vaccine or antigen induced specific antibody secretion from ex vivo circulating antibody-secreting lymphocytes

A method for detecting the level or the presence of antigen-specific antibodies secreted from a subject's antibody secreting cells, said method comprising the steps of (i) obtaining a sample comprising the supernatant of an in vitro culture of antibody secreting cells isolated from a subject after excluding serum antibodies from the in vitro culture, and (ii) determining the level or the presence of said antigen-specific antibodies in said sample;

• wherein the antibody secreting cells are in vivo stimulated by an antigen in the subject before isolating the antibody secreting cells from the subject, and the antibody secreting cells or the culture are not in vitro stimulated by the antigen or a part thereof prior to the determining step.