Production and characterization of IgA monoclonal antibody against ovalbumin

We established a hybridoma clone secreting an immunoglobulin A (IgA) monoclonal antibody (MAb) against ovalbumin (OVA). The MAb was produced using nasal-associated lymphoid tissues (NALT) of BALB/c mice that had been intranasally immunized with OVA together with cholera toxin. The isotype of the MAb was determined to be IgA, kappa. The established IgA MAb exhibited saturable and dose-dependent binding to immobilized OVA on ELISA. The majority of the antibodies formed a dimer on immunoblot analyses. To determine the affinity of each binding site, we performed surface plasmon resonance analysis, in which the binding of soluble OVA to immobilized IgA was measured. The results revealed a slow association rate and relatively low affinity of each binding site. Despite this, the stable binding of the MAb to the immobilized OVA suggests that IgA may gain high avidity through formation of the dimer. This hybridoma will provide a unique source of genuine IgA MAb, not an IgG-IgA chimeric one, against food allergens.