The impact of transgenic papaya (TPY10-4) fruit supplementation on immune responses in ovalbumin-sensitised mice

Abstract

A transgenic papaya line (TPY10-4) that is resistant to both papaya ringspot virus (PRSV) and papaya leaf distortion mosaic virus (PLDMV) has been developed in Taiwan. This study investigated the immunomodulatory properties of transgenic TPY10-4 and its native (TCK) papaya fruits using an ovalbumin (OVA)-sensitised mouse model. Both green and ripe papaya fruits at low (0.2 g powder kg(-1) body weight (BW)) and high (1.6 g powder kg(-1) BW) doses were administered to experimental mice by intragastric gavage for 5 weeks. Changes in serum total immunoglobulin A (IgA), IgE, IgG and IgM levels, OVA-specific IgE, IgG1 and IgG2a titres and Th1/Th2 cytokine secretions using splenocytes were determined. Transgenic TPY10-4 or native TCK papaya fruit supplementation did not significantly affect body, visceral organ and relative tissue weights, total IgE antibody levels, OVA-specific IgE and IgG1 antibody titres or OVA-stimulated interferon-γ (IFN-γ), interleukin-2 (IL-2), IL-4, IL-5 and IL-10 secretions using splenocytes. However, transgenic papaya fruits markedly increased serum total IgM levels. This study suggests that transgenic TPY10-4 papaya fruits do not increase the allergenic potential of OVA by oral administration but may have a protective immunity via increasing the serum total IgM level.