Comparison between Ovalbumin and Ovalbumin Peptide 323-339 Responses in Allergic Mice: Humoral and Cellular Aspects

Ovalbumin (OVA) is widely used in allergy research. OVA peptide 323-339 has been reported to be responsible for 25‐35% of isolated BALB ⁄c mouse T-cell response to intact OVA. An investigation of whether OVA and OVA 323-339 molecules can induce equivalent in vivo and in vitro immune responses was conducted. Eight-week-old BALB ⁄c mice were randomly divided into three groups: OVA, OVA 323-339 and saline. On days 0, 7, 14, mice were intraperitoneally injected with 25 lg OVA or OVA 323-339 absorbed on 300 lg Alum, or saline; on days 21‐23, all groups were challenged intranasally with either 20 ll of 1% OVA, 1% OVA 323-339 or saline. On day 28, after killing, splenocytes were isolated and cultured under the stimulus of each allergen or medium. Evaluated by hematoxylin ⁄eosin and major basic protein immunohistochemical stainings, OVA and OVA 323-339 induced similar lung inflammation. Interestingly, significant serum total IgE and OVA-specific IgE were observed in OVA mice when compared to saline control. OVA 323339 mice showed higher serum OVA-specific IgE, OVA 323-339-specific IgE, IL-4 and lower IFN-c similar to OVA mice. The proliferative response to OVA was found in cultured splenocytes of both OVA and OVA 323-339 mice, while the similar proliferative response to OVA 323-339 was only observed in the splenocytes of OVA 323-339-sensitized and challenged mice. Although OVA 323-339 induced a Th2-like response in the mouse model as did OVA, OVA 323-339 has clearly limited immunogenic potency to activate OVA-sensitized and challenged mice splenocytes, unlike OVA.