Hen's Egg Allergy Research Articles

CD4 +CD45RA + T cells modulate allergen-induced interleukin 2 responsiveness in human lymphocytes

Peripheral blood lymphocytes from nonallergic individuals acquired responsiveness to interleukin 2 (IL2) after stimulation with ovalbumin (OVA) or Dermatophagoides farinae (Df) antigens when they were pretreated with the CD45RA antibody, which has been shown to define the suppressor inducer subset of CD4 + cells and also to block its suppressor activity. The effect provided by the CD45RA antibody was lost if the lymphocytes had initially been activated with the OVA or Df antigens. The magnitude of the responses was comparable to the allergen-induced responses observed in OVA- or Df-sensitized lymphocytes from allergic patients. The pre-existing IL2 responsiveness in the patients was not increased by the CD45RA antibody pretreatment. However, the CD45RA antibody pretreatment gave rise to Df-induced IL2 responsiveness in the lymphocytes of the patients sensitized with OVA but not with Df; conversely, OVA-induced IL2 responsiveness was enhanced in Df- but not in OVA-sensitized lymphocytes. The CD45RA antibody apparently acts on CD4 + T cells, but not on CD8 + T cells, to induce the IL2 response. A further dissection of normal CD4 + T cells indicated that CD4 +45RA − T cells preferentially respond to IL2 after stimulation with OVA or Df antigens. Since normal CD4 +45RA + T cells did not show antigen-induced IL2 responsiveness even after pretreatment with the CD45RA antibody, it is unlikely that the CD45RA antibody stimulates CD4 +45RA + T cells to become responsive to IL2 after antigenic challenge. Alternately, CD4 +45RA + T cells may modulate the activity of CD4 +45RA − T cells, which are potentially responsive to IL2 by antigenic stimulation and thus provide tolerance in nonallergic lymphocytes. Collectively, a defective suppressor activity of CD4 +45RA + T cells may exist in patients with hen-egg allergy and/or bronchial asthma, which may cause lymphocytes to be hyperreactive to OVA or Df antigens.

Allergen-specific induction of interleukin-2 (IL-2) responsiveness in lymphocytes from children with asthma: II. Regulation of IL-2 responsiveness by supernatants of normal lymphocytes

Induction of interleukin-2 (IL-2) responsiveness by Dermatophagoides farinae (Df)-stimulated lymphocytes from children with asthma was markedly suppressed after the addition of culture supernatants from Df-stimulated normal T cells. Ovalbumin (OVA)-induced IL-2 responsiveness of lymphocytes from patients with hen-egg allergy was not suppressed by the supernatant from Df-stimulated T cells, indicating the antigenic specificity of the effect. Patients' lymphocytes whose IL-2 responsiveness was decreased still expressed Tac antigen (low-affinity IL-2 receptors) but, in contrast to the patients' original lymphocytes, did not absorb or respond to IL-2, suggesting the loss of high-affinity IL-2 receptors (p55/p75) from these cells. The supernatant from Df-stimulated normal T cells from one individual did not necessarily suppress the response of all patients tested, indicating the existence of some allogeneic barrier between the factor(s) and patients' lymphocytes.

Studies of food allergy--lymphocyte blastogenesis to ovalbumin or bovine serum albumin for detection of allergens in hen's egg and cow's milk allergy.

Studies of food allergy--lymphocyte blastogenesis to ovalbumin or bovine serum albumin for detection of allergens in hen's egg and cow's milk allergy.

Monoclonal Antibodies against Hen's Egg Ovomucoid

Two monoclonal antibodies (mAb 23E5 and 32A8) to hen's egg ovomucoid (OM), which causes hen's egg allergy and has trypsin inhibitory activity, were prepared and purified. Their affinity to the three separate domains of the ovomucoid, which are homologous in primary structure and are designated as DI, DII, and DIII, was studied by a competitive radioimmunoassay. MAb 23E5 bound to OM more efficiently than to DI, DII, or DIII-2 (with carbohydrate), but reacted with DIII-1 (free from carbohydrate) more efficiently than with OM. Except for the binding to OM, mAb 32A8 bound to DIII-2 most efficiently and to DIII-1 least efficiently, suggesting that this antibody recognized the carbohydrate moiety of DIII. MAb 32A8 inhibited the trypsin inhibitory activity of OM, whereas mAb 23E5 had no effect on it. These monoclonal antibodies should be useful for analyzing the antigenic determinants and trypsin inhibitory activity of ovomucoid.