Figure 4.

Different forms of antigen delivered by H-2^d-restricted tumours elicit high antigen-specific antibody titres in BALB/c mice. BALB/c mice were injected with antigen-transfected line 1 or EMT6 tumours (see Table 1). Tumours were allowed to grow for 16–21 days or until the mean leg diameter reached ≈12–14 mm. Mice were bled and the sera were assayed in antigen-specific enzyme-linked immunosorbent assays (ELISAs). Mouse antibodies were detected with horseradish peroxidase (HRP)- or alkaline phosphatase (AP)-conjugated goat anti-mouse immunoglobulin G (IgG), and the absorbance (A) was read at 490 or 405 nm, respectively. Antibody titre was determined as the inverse dilution that gave an A reading of twice background levels. This was carried out to normalize between the different ELISAs performed. Each point represents an individual mouse and the bar represents the geometric mean titre of all mice assayed. The standard error of the mean ranged between 980 and 2000 in mice injected with antigen-expressing line 1 tumours and 360–14 000 in mice injected with antigen-expressing EMT6 tumours.