Intranasal treatment with ovalbumin but not the major T cell epitope ovalbumin 323–339 generates interleukin-10 secreting T cells and results in the induction of allergen systemic tolerance

BACKGROUND: Nasal administration of major peptide T cell epitopes gives contradictory data on the induction of peripheral tolerance. OBJECTIVE: To compare the prophylactic effect of intranasal treatment (INT) on the development of an allergic response, using either ovalbumin (OVA) or its major T cell epitope OVA 323-339 (OVAp). METHODS: BALB/c mice were treated intranasally with OVA or OVAp and subsequently immunized s.c. with OVA. Anti-OVA-specific antibody, T cell proliferation and cytokine responses were analysed. In an adoptive transfer model using OVAp specific TCR transgenic (Tg) T cells from D011.10 mice, in vivo tracking and characterization of transferred T cells in the cervical, inguinal and bronchial lymph nodes (BLN) and in the spleen were determined by FACS analysis. RESULTS: Prophylactic INT with OVA induced T cell tolerance towards subsequent OVA s.c. immunizations, inhibiting OVA specific T cell proliferation, IgE and IgG1 production, in contrast to INT with OVAp, which was unable to induce tolerance. In vivo analysis of transferred OVA-specific TCR Tg T cells showed that INT with OVA induced a preferential activation of T cells in BLN, as opposed to a broad, systemic activation with OVAp. In vivo, OVAp INT led to faster and more sustained cell division cycles than OVA INT. Ex vivo, tolerance to OVA was associated with the generation of IL-10 secreting CD4(+) T cells in BLN of OVA-treated mice only. CONCLUSION: INT with OVA but not with OVAp led to regional (as opposed to systemic) T cell activation and the induction of IL-10 secreting CD4(+) T cells in BLN, potentially critical steps in the induction of T cell-specific tolerance via the nasal route.     

Characteristics of antibody responses induced in mice by protein allergens

Whereas many foreign proteins are immunogenic, only a proportion is also allergenic, having the capacity to induce the quality of immune response necessary to support the production of IgE antibody. We have demonstrated previously that intraperitoneal administration to mice of proteins such as ovalbumin (OVA) or the industrial enzyme A. oryzae lipase, which possess significant allergenic potential, stimulates the production of both IgG and IgE antibody. Identical exposure to bovine serum albumin (BSA), a protein with limited potential to cause immediate respiratory or gastrointestinal hypersensitivity reactions, induced IgG responses only. In the current investigations, the quality of immune responses induced following exposure to these proteins via mucosal tissue (intranasal) has been compared with those provoked following administration via a non-mucosal (intraperitoneal) route of exposure. Intranasal or intraperitoneal administration of BSA, OVA or A. oryzae lipase elicited in each case vigorous IgG and IgG1 antibody responses. For all three proteins, at every concentration tested, and via both routes of exposure, IgG1 antibody titres paralleled closely IgG titres. However, the three materials displayed a differential potential to provoke IgE responses and this correlated with their known allergenic potential in humans. Thus, OVA and A. oryzae lipase stimulated strong IgE antibody responses, whereas BSA provoked low titre IgE only at the highest concentration tested (5% administered intraperitoneally). The quality of induced responses was not affected by the route of exposure. It would appear, therefore, that the stimulation of IgG and IgG1 antibody responses is a reflection of protein immunogenicity whereas protein allergenicity is associated with the induction of strong IgE responses.     

Hydrophobic interactions in Plasmodium falciparum invasion into human erythrocytes

Human glycophorins block in vitro invasion of Plasmodium falciparum merozoites into human erythrocytes. A segment of glycophorin A which appears to be involved in the inhibition, is at, or adjacent to, the membrane-spanning domain of the molecule. To study the role of hydrophobic interactions in the inhibition, a series of proteins were derivatized with lipophilic side groups, and tested for inhibitory activity. Glycophorin A became five times more inhibitory after derivatization with nitrobenzylfurazan groups. Bovine serum albumin was derivatized to different degrees with nitrobenzylfurazan, dinitrobenzyl, trinitrobenzyl, dansyl, disulfonic stilbene, and fluorescein groups. The presence of hydrophobic side groups on the protein rendered it highly inhibitory to invasion, whereas the presence of hydrophilic substitutes such as disulfonic stilbenes did not. Other soluble proteins such as human serum albumin, transferrin, ovalbumin, fetuin and casein derivatized with dinitrobenzyl groups, were also found to block invasion. Inhibition was not a result of toxic effects of the protein derivatives on parasite metabolism or development. A minimum of ten hydrophobic side groups per bovine serum albumin was required in order to elicit appreciable inhibition. The invasion blocking activity was highly correlated with the rate and affinity of binding of the derivatized macromolecules to heptyl-Sepharose. The latter provided a quantitative measure for the capacity of amphiphiles to undergo hydrophobic interactions with insoluble matrices. The results of the present study indicate that hydrophobic interactions may be an essential component in the invasion of P. falciparum merozoites into human erythrocytes.     

Induction of specific anti-actin antibodies and their measurement by ELISA technique.

Using the ELISA technique we have been able to quantify antibodies directed against actin and to follow the kinetics of antibody production. Specific anti-actin antisera have been raised in rabbits by immunization with chemically modified white muscle rabbit actin. Two or three dinitrophenyl groups linked per actin molecule were sufficient to break natural tolerance, while linkage of three phosphorylcholine groups to actin was not.     

Humoral Immunity to Dietary Antigens in Atopic Dermatitis

Enzyme-linked immunosorbent assays (ELISA) employing a biotin-avidin amplification step are described for the quantification of human serum IgG antibodies to the dietary antigens ovalbumin (OA) and beta-lactoglobulin (BLG). The analytical quality of these assays was acceptable. Antibodies were measured in 16 patients with mild or moderate atopic dermatitis (AD), in 31 patients with a history of AD, and in closely matched controls. Levels of serum anti-OA antibodies did not differ in patients and controls, whereas anti-BLG antibodies tended to be higher in patients with mild or moderate AD than in controls (P less than 0.05).     

食管内脏高敏感性动物模型的建立和评价

目的建立食管内脏高敏感性动物模型。方法采用腹腔注射鸡卵清蛋白（OVA）基础致敏联合食管酸灌注的方法处理SD大鼠，并采用免疫组织化学方法和显微图像分析技术评价内脏高敏感性一食管化学刺激大鼠模型的可靠性。结果OVA基础致敏联合食管酸灌注组大鼠被激活了一个复杂而广泛的大脑网络，其在额顶皮质、岛叶、扣带皮质、中央杏仁核、Kfilliker-Fuse核、疑核、臂旁核、下丘脑室旁核、丘脑室旁核、三叉旁核、孤束核、最后区、延髓网状核等Fos样免疫活性（FLI）神经元的数目均显著高于其余各组（P〈0．05）。模型组大鼠在中央杏仁核、臂旁核、室旁核、三叉旁核、孤束核的FLI阳性产物的平均光密度（OD）值亦较其余各组明显增高（P〈0．05）。结论预先腹腔注射鸡卵清蛋白基础致敏联合食管酸灌注可成功建立食管内脏高敏感性动物模型。     

重组人白细胞介素-1受体拮抗药对豚鼠离体呼吸道平滑肌的影响

目的　观察人重组白细胞介素 1受体拮抗剂 (IL 1ra)对正常和卵白蛋白致敏豚鼠离体肺条、气管平滑肌的影响。方法　应用离体器官装置、张力换能器、MedLab记录系统测定肺条和气管平滑肌的张力。结果　①IL 1ra对正常豚鼠离体肺条和气管平滑肌有直接松弛作用 ,EC50 分别为1 2 9ⅹ 10 -7mol·L-1和 8 0 6× 10 -8mol·L-1;并对卵白蛋白致敏的豚鼠肺条和气管平滑肌也有直接的松弛作用 ,EC50 分别为 2 6 1× 10 -7mol·L-1和 5 88× 10 -7mol·L-1,但致敏豚鼠呼吸道平滑肌对IL 1ra的敏感性要比正常豚鼠低。②IL 1ra(10 -9～ 10 -5mol·L-1)可剂量依赖性地抑制致痉剂组胺对正常豚鼠肺条和气管平滑肌的收缩作用 (P <0 0 1)。③IL 1ra能抑制卵白蛋白攻击引起的肺条和气管平滑肌的收缩 ,IC50 分别为 7 83ⅹ 10 -7mol·L-1和 4 4 8ⅹ 10 -7mol·L-1。结论　IL 1ra对正常、痉挛及致敏状态的呼吸道平滑肌均有松弛作用     

Plasmodium falciparum synthetic LbL microparticle vaccine elicits protective neutralizing antibody and parasite-specific cellular immune responses

Epitopes of the circumsporozoite (CS) protein of Plasmodium falciparum, the most pathogenic species of the malaria parasite, have been shown to elicit protective immunity in experimental animals and human volunteers. The mechanisms of immunity include parasite-neutralizing antibodies that can inhibit parasite motility in the skin at the site of infection and in the bloodstream during transit to the hepatocyte host cell and also block interaction with host cell receptors on hepatocytes. In addition, specific CD4+ and CD8+ cellular mechanisms target the intracellular hepatic forms, thus preventing release of erythrocytic stage parasites from the infected hepatocyte and the ensuing blood stage cycle responsible for clinical disease. An innovative method for producing particle vaccines, layer-by-layer (LbL) fabrication of polypeptide films on solid CaCO₃ cores, was used to produce synthetic malaria vaccines containing a tri-epitope CS peptide T1BT* comprising the antibody epitope of the CS repeat region (B) and two T-cell epitopes, the highly conserved T1 epitope and the universal epitope T*. Mice immunized with microparticles loaded with T1BT* peptide developed parasite-neutralizing antibodies and malaria-specific T-cell responses including cytotoxic effector T-cells. Protection from liver stage infection following challenge with live sporozoites from infected mosquitoes correlated with neutralizing antibody levels. Although some immunized mice with low or undetectable neutralizing antibodies were also protected, depletion of T-cells prior to challenge resulted in the majority of mice remaining resistant to challenge. In addition, mice immunized with microparticles bearing only T-cell epitopes were not protected, demonstrating that cellular immunity alone was not sufficient for protective immunity. Although the microparticles without adjuvant were immunogenic and protective, a simple modification with the lipopeptide TLR2 agonist Pam₃Cys increased the potency and efficacy of the LbL vaccine candidate. This study demonstrates the potential of LbL particles as promising malaria vaccine candidates using the T1BT* epitopes from the P. falciparum CS protein.