Biology · Immunology

Four groups of students (A-D) were asked to determine whether memory B cells generated in mice immunized with ovalbumin (OVA), in Complete Freund's adjuvant (CFA), could mount a secondary antibody response (recall response) to OVA in vitro. The groups did the following experiments: - Group A: Harvested serum from the mice, loaded it on OVA-coated ELISA plates and showed that IgG and IgA anti-OVA antibodies were present. - Group B: Harvested long-lived plasma cells from bone marrow of the mice, plated them in culture for 5 days and showed anti-OVA antibodies in supernatant by ELISA. - Group C: Infected an epithelial cell line with the virus and showed that spleen cells from the mice could kill the infected targets. - Group D: Stimulated spleen cells from the mouse with OVA for 5 days and showed anti-OVA antibodies in supernatant by ELISA. Which one of the following options represents the group(s) that did the correct experiment?