OVA Peptide 323-339

The epitopes for OVA323-339-specific CD4⁺T cells from OVA23-3 food allergy model and DO11.10 tolerant induction model mice were analyzed. We found that OVA23-3 CD4⁺T cells recognized the N-terminal region, showing strong proliferation and the Th2-phenotype, and that DO11.10 CD4⁺T cells recognized the C-terminal region, showing milder proliferation and a Th1-skewed response. These differences may regulate the responses of those mice to OVA-feeding, inflammation and tolerance.

Dendritic cells (DC) are the primary APC responsible for the capture of allergens in the airways and the shuttling of processed allergens to the draining lymph nodes where Ag presentation and T cell activation take place. The mechanism of this Ag handling and presentation in asthma is poorly understood. In addition, the feasibility of asthma induction by DC priming has not been directly tested. In this report an asthma model using intratracheally (i.t.) injected splenic DC was used to address these issues. DC pulsed with a model Ag OVA or the major MHC class II-restricted OVA T epitope peptide OVA(323-339) and instilled i.t. primed mice to exhibit asthma-like diseases. With OVA as the Ag, mice exhibit airway hyperresponsiveness (AHR), lung eosinophilia and inflammation, and pulmonary goblet cell hyperplasia. In OVA(323-339)-immunized mice, AHR and goblet cell hyperplasia were noted, with little eosinophilia and parenchymal inflammation. The latter finding provides evidence for dissociating AHR from eosinophilia. In both cases mediastinal node hypertrophy occurred, and high levels of Th2 cytokines were produced by the lung and mediastinal lymph node cells (LNC). Interestingly, mediastinal LNC also produced high levels of Th1 cytokines. Lung cells produced much less Th1 cytokines than these LNC. These results demonstrate that DC when introduced i.t. are potent in inducing asthma-like diseases by recruiting lymphocytes to the lung-draining lymph nodes and by stimulating Th2 responses and also suggest that the lung environment strongly biases T cell responses to Th2.

Vaccines are arguably the most important medical technology developed to date. However, effective treatment of diseases such as breast cancer have so far evaded standard vaccination strategies. One popular target for cancer treatment is the cell surface membrane protein, ErbB-2, also known as Her-2 or neu. It is localised to the cell surface and has raised expression in 15-30% of all breast cancers, as well as in ovarian, colon and lung cancer. Here, a liposomal system comprised of spatially separated ErbB-2 peptide, to activate B cells, and ovalbumin peptide OVA323-339, to provide non-cognate T cell support, was used to generate antibodies against the epitope of the ErbB-2 protein targeted by Pertuzumab, a monoclonal antibody licensed for the treatment of ErbB-2 expressing cancers. After just 7 days a raised (7.3-fold, p<0.01), isotype-switched, humoral immune response specific for the ErbB-2 peptide was achieved in mice with pre-existing immunity to OVA which were exposed to liposomes with external ErbB-2 and internal OVA323-339. The absence of pre-existing OVA immunity in the mice or OVA323-339peptide in the liposomes removed the effect. The effect of this anti-ErbB-2 antibody response was characterised against an ErbB-2 overexpressing tumour cell line both in vitro and in vivo. Notably, antibody responses were demonstrated to induce cell death in vitro, resulting in 96% reduction in viable cells. This study, therefore, demonstrates the feasibility of this approach to generate a rapid, high-titre, isotype-switched, antibody response that specifically targets ErbB-2 overexpression on tumour cells and is capable of inducing cell death in vitro in the absence of complement or immune cells.

Background:Myeloperoxidase (MPO)-ANCA-associated GN is a significant cause of renal failure. Manipulating autoimmunity by inducing regulatory T cells is potentially a more specific and safer therapeutic option than conventional immunosuppression.Methods:To generate MPO-specific regulatory T cells, we used a modified protein-conjugating compound, 1-ethyl-3-(3'dimethylaminopropyl)-carbodiimide (ECDI), to couple the immunodominant MPO peptide (MPO409-428) or a control ovalbumin peptide (OVA323-339) to splenocytes and induced apoptosis in the conjugated cells. We then administered MPO- and OVA-conjugated apoptotic splenocytes (MPO-Sps and OVA-Sps, respectively) to mice and compared their effects on development and severity of anti-MPO GN. We induced autoimmunity to MPO by immunizing mice with MPO in adjuvant; to trigger GN, we used low-dose antiglomerular basement membrane globulin, which transiently recruits neutrophils that deposit MPO in glomeruli. We also compared the effects of transferring CD4+T cells from mice treated with MPO-Sp or OVA-Sp to recipient mice with established anti-MPO autoimmunity.Results:MPO-Sp but not OVA-Sp administration increased MPO-specific, peripherally derived CD4+Foxp3-type 1 regulatory T cells and reduced anti-MPO autoimmunity and GN. However, in mice depleted of regulatory T cells, MPO-Sp administration did not protect from anti-MPO autoimmunity or GN. Mice with established anti-MPO autoimmunity that received CD4+T cells transferred from mice treated with MPO-Sp (but not CD4+T cells transferred from mice treated with OVA-Sp) were protected from anti-MPO autoimmunity and GN, confirming the induction of therapeutic antigen-specific regulatory T cells.Conclusions:These findings in a mouse model indicate that administering apoptotic splenocytes conjugated with the immunodominant MPO peptide suppresses anti-MPO GN by inducing antigen-specific tolerance.