OVA-specific antibody-mediated immune responses in lung washes from newborn piglets gavaged with OVA then i.p. immunized with OVA at four weeks of age. Piglets (n = 5/group) were gavaged and i.p. immunized as described in Figure 1. Control newborn piglets were not gavaged or immunized with OVA. Lung lavages were collected four weeks post i.p. immunization and OVA-specific serum IgM (A), IgA (B), IgG (C), IgG1 (D), and IgG2 (E) titres were measured. ELISA titres are expressed as the reciprocal of the highest dilution resulting in a reading of two standard deviations above the negative control. Each data point represents an individual animal and median values are indicated by horizontal lines. *p < 0.05, **p < 0.01.