异种抗原瘤内注射对荷瘤小鼠肿瘤生长的抑制作用

背景:异种抗原的免疫原性比较强,容易引起较强的免疫应答。如果将异种抗原直接引入肿瘤内部,在肿瘤内部引发一系列免疫反应,有可能逆转肿瘤微环境的免疫抑制状态,达到抗肿瘤的目的。目的:评价人红细胞膜抗原瘤内注射对荷S180肉瘤小鼠肿瘤生长的抑制作用。方法:复制昆明小鼠S180肉瘤皮下瘤模型,瘤内注射质量浓度为5g/L的人红细胞膜抗原或生理盐水,连续注射5d,记录注射前及注射第3,7,14天肿瘤体积变化。同时设肿瘤细胞与人红细胞膜抗原同时接种组、免疫后瘤内注射人红细胞膜抗原组、免疫后瘤内注射生理盐水组。另取60只小鼠复制S180肉瘤皮下瘤模型,免疫及瘤内注射人红细胞膜抗原或生理盐水同前。注射第14天每组处死6只小鼠,肿瘤称质量,行病理学分析,每组剩余小鼠继续观察生存情况。结果与结论:各组小鼠肿瘤体积逐渐增大,第14天人红细胞膜抗原与肿瘤细胞同时接种组、免疫后人红细胞膜抗原瘤内注射组、人红细胞膜抗原瘤内注射组肿瘤体积均小于瘤内注射生理盐水组。瘤内注射人红细胞膜抗原可显著降低肿瘤质量。瘤内注射人红细胞膜抗原后镜下可见肿瘤细胞坏死、淋巴细胞等炎症细胞浸润。未观察到各组小鼠生存期有明显差别。结果表明异种红细胞膜抗原瘤内注射可以抑制小鼠S180肉瘤肿瘤生长。     

SBHL对S180荷瘤小鼠肿瘤生长及免疫功能的影响

目的:探讨SBHL对肿瘤的作用效果及其抗肿瘤免疫效应机制。方法:选用S180荷瘤小鼠,采用腹腔注射SBHL[10、30、50mg/(kg·d)],连续注射14天,观察肿瘤生长及SBHL对小鼠免疫功能的影响。结果:SBHL能显著抑制荷瘤小鼠S180肉瘤的生长。SBHL对荷瘤小鼠受抑的细胞免疫功能具有明显正向调节作用,能提高脾淋巴细胞增殖及IL-2产生能力,增强NK和LAK细胞活性。结论:SBHL能明显抑制肿瘤的生长,SBHL的免疫增强效应可能是其发挥抗肿瘤作用的重要途径。     

过继肿瘤特异性淋巴细胞联合mIL-21瘤苗抗肿瘤效应研究

目的 在环磷酰胺(Cy)所致小鼠淋巴细胞急剧减少状态下,过继mIL-21转染的瘤苗细胞(mIL-21-Sp2/0)免疫致敏的同系小鼠淋巴细胞,联合mIL-21-Sp2/0瘤苗免疫,探讨过继免疫抗瘤效应机制.方法 用Cy 100 mg/kg预处理BALB/c小鼠2 d后,以灭活mIL-21瘤苗免疫的同系小鼠脾及淋巴结的淋巴细胞作为肿瘤抗原特异性淋巴细胞过继给Cy预处理鼠,同时用mIL-21瘤苗免疫,7 d后以野生型Sp2/0细胞攻击,观察小鼠的肿瘤生长情况.流式细胞仪(FCM)分析CD4+、CD8+、CD4+CD25+T细胞等亚群的变化,分别以CFSE和7-AAD标记,FCM检测淋巴细胞增殖能力和效应细胞的细胞毒活性,用ELISPOT检测分泌IFN-γ的淋巴细胞数量.结果 与对照组相比,Cy预处理小鼠接受过继效应细胞及mIL-21瘤苗免疫后,可有效地抵抗野生型Sp2/0细胞的攻击.过继的肿瘤特异性淋巴细胞的体内增殖能力和体外杀伤活性显著增强,分泌IFN-γ效应细胞的数量显著增高.结论 在小鼠淋巴细胞减少期,过继mIL-21瘤苗免疫致敏的肿瘤抗原特异性淋巴细胞并同时给予mIL-21瘤苗免疫,利于输入的效应细胞及自身免疫细胞的增殖和特异性抗肿瘤功能的形成与维持.     

肺炎结合疫苗PPS14-OVA、PPS14-C3d在小鼠脾脏的定位及补体对定位的影响

目的检测血清型14型肺炎球菌荚膜多糖(PPS14)结合疫苗PPS14-OVA(卵清蛋白)、PPS14-C3d(补体)免疫小鼠后在脾脏细胞中的定位,以及补体对其定位的影响。方法PPS14-OVA、PPS14-C3d经皮下或静脉注射,免疫正常小鼠和眼镜蛇毒因子(CVF)预处理的小鼠,应用免疫荧光技术检测脾脏冰冻切片中的PPS14及各种免疫细胞。结果正常小鼠免疫PPS14-OVA后,PPS14-OVA定位于脾脏;1 h后与脾脏边缘区B细胞有结合;2 h后出现在淋巴滤泡中;6 h后全部转移至淋巴滤泡,并与滤泡B细胞和树突状细胞结合,与巨噬细胞和T细胞没有结合。而CVF预处理的小鼠,PPS14-OVA不定位于脾脏。PPS14-C3d在脾脏中的定位不受CVF处理的影响。结论 PPS14-OVA在脾脏中的定位需要补体的介导,而PPS14-C3d不需要。     

NKT细胞在CFA促进的Th1型免疫应答中的作用

为探索CFA促进小鼠对蛋白质抗原产生Th1介导的特异性免疫应答的机制 ,我们用OVA +CFA和OVA +IFA免疫C5 7BL/6小鼠 ,并于第 3天、第 8天后用MACS +FACS法分离引流淋巴结中NKT细胞 ,在体外经CD3单抗刺激 2d后测定其分泌的细胞因子数量及格局。同时于免疫后第 8天分离引流淋巴结抗原特异性T细胞 ,测定其分泌细胞因子的格局 ;并于再次免疫后 2周检测小鼠血清抗体类型。ELISA结果显示 ,与OVA +IFA组相比 ,OVA +CFA免疫小鼠引流淋巴结NKT细胞和抗原特异性T细胞分泌IFN γ的能力均显著升高 (P <0 0 5 ) ,且血清抗体类型以IgG2a为主。表明CFA促进抗原特异性Th0细胞极化为Th1细胞可能是通过激活NKT细胞使之在免疫应答局部产生大量的IFN γ而实现的     

胃癌细胞总RNA修饰树突状细胞的肿瘤疫苗效果

目的应用肿瘤细胞RNA修饰小鼠树突状细胞(dendrticcell,DC)的肿瘤疫苗免疫小鼠,研究其抗肿瘤免疫作用.方法CD11c磁珠抗体标记小鼠脾单个核细胞悬液,磁性细胞分选器(MACS)分选出CD11c+的DC,短期培养,以肿瘤细胞总RNA脉冲DC,以此瘤苗皮下注射免疫615小鼠两次,间隔1周,最后1次免疫后7d,实验鼠皮下接种5×105小鼠前胃癌细胞(MFC).结果经免疫后的小鼠具有较强抗肿瘤免疫,RNA脉冲DC的瘤苗免疫后肿瘤生长受到明显抑制,其外周血和脾细胞中NK活性均明显升高,肿瘤特异性CTL也明显升高.结论以肿瘤RNA作为抗原脉冲DC可诱导较强的抗肿瘤免疫.     

阿霉素联合致敏树突状细胞对荷宫颈癌小鼠的治疗作用

 目的：探讨阿霉素(adriamycin,ADM)联合冻融抗原致敏的树突状细胞(dendritic cells,DCs)对荷宫颈癌小鼠的免疫治疗作用。方法：建立小鼠皮下移植瘤模型;应用反复冻融法处理小鼠宫颈癌U14细胞,并致敏小鼠骨髓来源的DCs,制备DCs疫苗;流式细胞术鉴定DCs成熟表型;荷瘤小鼠分为对照组（PBS组）、DCs疫苗组、ADM组和ADM联合DCs疫苗组,进行3个周期的治疗。观察肿瘤大小,第21 d取血,ELISA法检测小鼠血清IL-2、IL-12和IFN-γ含量;处死动物,称肿瘤重量。结果：肿瘤冻融抗原致敏DCs后,可高表达白细胞分化抗原CD11c、CD80和CD86;经3个周期的治疗后,ADM联合DCs疫苗组平均瘤重及平均瘤体积均小于ADM组、DCs疫苗组和对照组(P＜0.05),联合治疗组抑瘤率大于其它3组(P＜0.05),且血清IL-2、IL-12和IFN-γ水平明显升高 (P＜0.05)。结论：ADM联合肿瘤抗原致敏的DCs疫苗可增强动物的抗肿瘤免疫应答,能有效抑制荷宫颈癌小鼠肿瘤的生长。     

CpG增强DC疫苗对黑色素瘤B16-HLA-MAGE-3的免疫效果

目的:观察CpG对抗原肽负载DC疫苗免疫效果的增强作用.方法:分别用50 μg/ml的MAGE-3271-279抗原肽、4 μg/ml的CpG和MAGE-3271-279抗原肽(50 μg/ml)+CpG(4 μg/ml)刺激培养到第6天的小鼠骨髓DC细胞,2天后用LPS再刺激24 小时诱导其成熟;给HLA-A·0201/Kb转基因鼠移植B16-HLA-MAGE-3黑色素瘤,并于小鼠荷瘤的第-4、5和8天分别于颈部皮下注射同系小鼠DC疫苗(2×105/鼠),观察荷瘤鼠肿瘤生长情况;在荷瘤的第23 天处死小鼠,检测脾脏NK细胞活性.给正常HLA-A2转基因小鼠皮下注射DC疫苗,8周后接种肿瘤细胞,观察免疫记忆形成情况.结果:抗原肽负载的DC疫苗,在小鼠荷瘤的第14天之前,小鼠肿瘤生长受到抑制,在第15天后抑瘤作用不明显;CpG与MAGE-3271-279+CpG负载的DC疫苗可显著抑制荷瘤鼠肿瘤的生长,且可诱导较高的NK细胞活性.MAGE-3271-279+CpG负载的DC疫苗在免疫8周后依然可抑制肿瘤细胞的生长,说明可以诱导免疫记忆形成.结论:CpG对抗原肽负载的DC疫苗的免疫效果具有潜在的增强作用.     

重组人Hsp70提呈的H22肝癌细胞混合抗原肽治疗小鼠肿瘤的研究

目的：探讨B22肝癌细胞混合抗原肽体内抑制小鼠肿瘤的最佳方式。方法：采用冻融，低渗振荡，加热沉淀及酸处理等方法从H22肝癌细胞中制备抗原肽；将接种过H22瘤细胞的小鼠分别给予Hsp70-H22肽复合物注射，复合物＋pCH510质粒注射或化疗后给予复合物＋质粒注射，观察肿瘤抑制情况。结果：上述方法制备的抗原肽为混合肽，其与Hsp70形成的复合物体内能够抑制小鼠肿瘤生长，并且这种复合物可与pCH510质粒协同完全抑制10^5接种的瘤细胞形成肿 瘤，但不能完全抑制10^6接种的瘤细胞形成肿瘤，然而这种双因素与化疗进行衔接则可完全抑制10^6接种的瘤细胞形成肿瘤。结论：H22肝癌细胞肿瘤混合抗原肽经rhHsp70提呈可诱导H22荷瘤小鼠产生特异性免疫保护作用，与其它因素联合应用可产生更好的治疗效果。     

CEA抗原表位串联体与FL共表达基因疫苗抑制小鼠肝癌细胞体内生长的研究

目的:观察CEA抗原表位串联体与FL共表达基因疫苗抑制荷瘤小鼠肿瘤生长。方法:利用基因重组技术将CEA抗原表位三串联体和FL基因片段克隆到质粒pcDNA3.0上,肌注免疫BALB/c小鼠,观察重组基因疫苗对CEA阳性肿瘤的抑制作用、小鼠生存时间及其诱导小鼠杀伤效应细胞的活性。结果:pcDNA-triCEA625-667-sFL免疫组小鼠生存时间延长,肿瘤生长速度缓慢,瘤块较小,与对照组小鼠比较有显著性差异(P0.01);经pcDNA-triCEA625-667-sFL免疫的小鼠脾细胞对H22-CEA+的杀伤率明显升高,差异有显著性(P0.01)。结论:共表达三倍体CEA抗原表位和FL的基因疫苗可以有效抑制CEA阳性肿瘤在小鼠体内的生长,并增强小鼠杀伤效应细胞的活性。     

过继转输的肿瘤特异性T杀伤细胞在小鼠体内维持杀伤功能的研究

体外试验从免疫小鼠脾细胞中诱导出对ＦＢＬ－３瘤细胞具有特异性杀伤功能的Ｔ杀伤细胞，转输到同系正常小鼠体内后发现，同时给予肿瘤抗原刺激和７ｄｒＩＬ－２作用，可使受鼠脾细胞获得杀伤ＦＢＬ－３细胞的活性，其杀伤功能与转输的Ｔ杀伤细胞有关，若转输后连续２１ｄ只给予ｒＩＬ－２不能维持体内建立的杀瘤活性，而间断给予肿瘤抗原再刺激，并联合应用短程ｒＩＬ－２，以１４ｄ为１周期，则可长期维持体内的肿瘤特异性杀伤功能     

The kinetics of oral hyposensitization to a protein antigen are determined by immune status and the timing, dose and frequency of antigen administration.

We have investigated the immunological consequences of feeding a protein antigen to previously immunized animals. BALB/c mice were systemically primed with ovalbumin (OVA) in complete Freund's adjuvant (CFA) and fed with high (10 mg/g body weight), medium (1 mg/g body weight) or low (1 microgram/g body weight) doses of OVA once (Day 1, 7 or 14) or sequentially for 5 days (Days 1-5, 7-11, 14-18). The specific IgG antibody response was suppressed only by early feeds of high-dose OVA (Days 1-5). Medium-dose OVA fed on Day 14 or low-dose OVA fed at any stage after immunization enhanced the IgG antibody response. In contradistinction, systemic delayed-type hypersensitivity responses (DTH) were usually suppressed by early feeds of high or medium doses of OVA but never after feeding low-dose OVA. The results suggest that systemic DTH and IgG antibody responses to oral antigen are subject to different control mechanisms in previously primed animals. Such responses depend on the immune status of the animal and are controlled by antigen dose, time and frequency of feeding. The immunological effects observed are also demonstrable following adoptive transfer of spleen cells collected 14 days after multiple feeds of high-dose OVA to immunized mice. Our findings suggest that oral hyposensitization after systemic immunization is regulated by (suppressor) spleen cells which are activated by gut-processed antigen.     

Combination tumor immunotherapy with radiotherapy and Th1 cell therapy against murine lung carcinoma

Mice bearing established Lewis lung carcinoma (LLC) expressing model tumor antigen, ovalbumin (OVA) (LLC-OVA) marginally responded to local radiotherapy, but none of the mice was cured. In contrast, treatment of the tumor-bearing mice with intratumoral injection of tumor-specific T helper type 1 (Th1) cells and tumor antigen (OVA) after radiotherapy dramatically prolonged the survival days and induced complete cure of the mice at high frequency (80%). Radiation therapy combined with Th1 cells or OVA alone showed no significant therapeutic activity against LLC-OVA. Such a strong therapeutic activity was not induced by intratumoral injection of Th1 cells plus OVA. Compared with other treatment, radiation therapy combined with Th1 cells and OVA was superior to induce the generation of OVA/H-2^b tetramer⁺ tumor-specific cytotoxic T lymphocyte (CTL) with a strong cytotoxicity against LLC-OVA in draining lymph node (DLN). Moreover, the combined therapy is demonstrated to inhibit the growth of tumor mass, which grew at contralateral side. These results indicated that radiotherapy combined with Th1 cell/vaccine therapy induced a systemic antitumor immunity. These findings suggested that combination therapy with radiotherapy and Th1 cell/vaccine therapy may become a practical strategy for cancer treatment. Hiroshi Yokouchi and Kenji Chamoto are equally contributed.     

Depletion of complement has distinct effects on the primary and secondary antibody responses to a conjugate of pneumococcal serotype 14 capsular polysaccharide and a T-cell-dependent protein carrier

Complement activation plays a critical role in the immune response to T-cell-dependent and T-cell-independent antigens. However, the effect of conjugation of T-cell-dependent protein carriers to T-cell-independent type 2 antigens on the requirement for complement in the humoral immune response to such antigens remains unknown. We studied the role of complement activation on the antibody response of BALB/c mice immunized with the T-cell-independent type 2 antigen serotype 14 pneumococcal capsular polysaccharide (PPS14), either in unmodified form or conjugated to ovalbumin (OVA). In mice immunized with either PPS14 or PPS14-OVA, depletion of endogenous complement at the time of primary immunization by treatment with cobra venom factor (CVF) diminished serum anti-PPS14 concentrations after primary immunization but enhanced antibody responses after secondary immunization. The secondary immunoglobulin G (IgG) anti-PPS14 antibody response after immunization with PPS14-OVA was especially enhanced by complement depletion, was observed at doses as low as 0.2 mug of antigen, and was maximal when CVF was administered within 2 days of immunization. The avidity and opsonophagocytic functions of IgG anti-PPS14 antibodies were comparable in mice immunized with PPS14-OVA with or without complement depletion. Serum anti-PPS14 antibody concentrations were near normal, and the enhancing effects of CVF treatment on the secondary anti-PPS14 antibody response were also apparent in splenectomized mice immunized with PPS14-OVA. These results demonstrate that complement activation can have distinct effects on the primary and secondary antibody responses to a T-cell-independent type 2 antigen, either unmodified or conjugated to a T-cell-dependent protein carrier. These differences should be taken into consideration when using complement to modulate the immune response to vaccines.     

Establishment of tumor-specific immunotherapy model utilizing vaccinia virus-reactive helper T cell activity

It was previously demonstrated that preimmunization of mice with live vaccinia virus (VV) and subsequent immunization with VV-infected (modified), syngeneic tumor cells resulted in enhanced induction of tumor-specific immunity through a cellular collaboration between VV-reactive helper T (VV-Th) cells and tumor-specific effector cell precursors. On the basis of this augmenting system, a tumor-specific immunotherapy model was established in which a growing tumor regressed. C3H/HeN mice were pretreated with cyclophosphamide to eliminate nonspecific suppressor T cell activity and subsequently inoculated (primed) s.c. with live VV, leading to augmented induction of VV-Th cell activities. Four weeks later, the mice were inoculated i.d. with syngeneic X5563 myeloma cells. Six days after the tumor cell inoculation, live VV was injected into the tumor mass three times at 2-day intervals. Seven of ten mice which had received VV priming and subsequent VV injection into the tumor mass exhibited complete tumor regression. On the contrary, mice which had received mere intratumoral VV injection in the absence of VV priming failed to exhibit appreciable tumor regression. Mice whose tumor had completely regressed (regressor mice) by the above VV immunotherapy were shown to have acquired systemic anti-tumor immunity, which was confirmed by a challenge with syngeneic tumor cells after the tumor regression. In vitro analysis of these immune mice revealed that potent tumor-specific cytotoxic T lymphocyte responses were preferentially induced, but with no detectable anti-tumor antibody responses. Such a potent tumor-specific immunity was not observed in mice which had received an intratumoral VV injection in the absence of VV priming. Thus the results clearly indicate that the tumor regression was accompanied by concurrent generation of a potent tumor-specific immunity, suggesting that the cellular collaboration between VV-Th cells and tumor-specific effector cell precursors is also functioning in this VV-immunotherapy protocol, likewise the immunoprophylactic model. Therefore, the present model provides an effective maneuver for tumor-specific immunotherapy and this system will be theoretically applicable to human cancer treatment.     

Immune effector cells induced by complete Freund's adjuvant exert an inhibitory effect on antigen-specific type 2 T helper responses

Background II has hecn well documented that environmental factors such as antigenpresenting cells and related cytokines could affect the development of T helper cells. Objective The purpose of this study is to investigate the effect of different adjuvants on T cell development. Methods Ovalbumin (OVA) combined with aluminum hydroxide (Alum) plus pertussis toxin (PT) or complete Freund's adjuvant (CFA) were used to sensitize mice; the production of IgG and IgE anli-OVA antibodies was then followed. In addition, OVA-specific proliferative responses and cytokine production by spleen cells were also investigated. Results The data showed that the adjuvants themselves could modify the pattern of immune response: (1) IgG_2a > anti-OVA antibody was higher in mice sensitized with OVA + CFA compared to that of mice sensitized with OVA + Alum + PT; (2) the ratio of IFN-γ/IL-4 produced by OVA-stimutated spleen cells was higher in mice sensitized with OVA + CFA than that of mice sensitized with OVA + Alum + PT; (3) increased percentage of γδ T cells was noted in the peritoneal exudate cells of OVA + CFA immunized mice; and (4) the immune response of mice sensitized wilh OVA + Alum+ PT was inhibited by the adoptively transferred ascitic cells from OVA + CFA immunized mice. Conclusion In general, the data suggested higher IgG2a and the ratio of IFN-γ/IL-4 was noted In mice sensitized with OVA + CFA. Further elucidation of the regulatory mechanism of allergen-specific T helper cells development and exploration of possible agents for inmiunotherapy might shed light on the management of atopic diseases.     

Direct evidence for anergy in T lymphocytes tolerized by oral administration of ovalbumin

The present study investigated bystander suppression, specific suppression and anergy as mechanisms for oral tolerance. Oral tolerance was induced in mice by a single gastric intubation of 20 mg ovalbumin (OVA) and was evaluated in vitro by the absence of T lymphocyte proliferative responses to OVA after priming by OVA-complete Freund's adjuvant (CFA). T lymphocyte unresponsiveness was antigen specific, systemic and was not affected by the vehicle used for immunization. T lymphocytes derived from tolerant popliteal lymph nodes (PLN) responded to an acetone precipitate (AP) of mycobacteria present in CFA; this response was not suppressed by co-culture with OVA, thereby arguing against a mechanism of bystander suppression in our system. Responses of PLN T lymphocytes derived from OVA-CFA primed, non-tolerant mice, or those of an OVA-specific T lymphocyte line, were not suppressed by PLN or spleen cells derived from OVA tolerant mice. These results excluded the possibility that oral tolerance was induced and maintained by a mechanism of specific suppression. At the cellular level, we found that OVA-tolerant T lymphocytes did not produce interleukin-2 (IL-2) nor express IL-2 receptor in response to OVA stimulation in vitro; both observations are indicative of a state of anergy. Incubation of OVA-tolerant PLN T lymphocytes together with murine recombinant IL-2 for 5 days, released anergic T lymphocytes and a concomitant OVA-specific proliferative response of CD4⁺ T cells was detected. Taken together, our experimental system excludes the involvement of bystander or specific suppression in the induction of oral tolerance to OVA, and provides direct evidence to show that oral tolerance results from specific T lymphocyte anergy.     

T cell-mediated oral tolerance is intact in germ-free mice

Commensal enteric bacteria stimulate innate immune cells and increase numbers of lamina propria and mesenteric lymph node (MLN) T and B lymphocytes. However, the influence of luminal bacteria on acquired immune function is not understood fully. We investigated the effects of intestinal bacterial colonization on T cell tolerogenic responses to oral antigen compared to systemic immunization. Lymphocytes specific for ovalbumin-T cell receptor (OVA-TCR Tg(+)) were transplanted into germ-free (GF) or specific pathogen-free (SPF) BALB/c mice. Recipient mice were fed OVA or immunized subcutaneously with OVA peptide (323-339) in complete Freund's adjuvant (CFA). Although the efficiency of transfer was less in GF recipients, similar proportions of cells from draining peripheral lymph node (LN) or MLN were proliferating 3-4 days later in vivo in GF and SPF mice. In separate experiments, mice were fed tolerogenic doses of OVA and then challenged with an immunogenic dose of OVA 4 days later. Ten days after immunization, lymphocytes were restimulated with OVA in vitro to assess antigen-specific proliferative responses. At both high and low doses of OVA, cells from both SPF and GF mice fed OVA prior to immunization had decreased proliferation compared to cells from control SPF or GF mice. In addition, secretion of interferon (IFN)-gamma and interleukin (IL)-10 by OVA-TCR Tg(+) lymphocytes was reduced in both SPF and GF mice fed OVA compared to control SPF or GF mice. Unlike previous reports indicating defective humoral responses to oral antigen in GF mice, our results indicate that commensal enteric bacteria do not enhance the induction of acquired, antigen-specific T cell tolerance to oral OVA.     

Essential role of dendritic cell CD80/CD86 costimulation in the induction, but not reactivation, of TH2 effector responses in a mouse model of asthma

BACKGROUND: Airway dendritic cells (DCs) are crucial for the generation of TH2 cells from naive T cells during sensitization and for reactivation of primed TH2 cells on allergen challenge in mouse models of asthma. It is unknown whether CD80/CD86 costimulation is necessary during both phases of the response because primed T cells rely less on costimulatory molecules compared with naive T cells. OBJECTIVE: We sought to study the contribution of CD80/CD86 costimulatory molecules on DCs during sensitization or challenge in a mouse model of asthma. METHODS: Naive BALB/c mice received an intratracheal injection of ovalbumin (OVA)-pulsed DCs obtained from the bone marrow of wild-type (WT) or CD80/CD86-/- mice and were subsequently challenged with OVA aerosol to address the role of costimulation during sensitization. OVA-sensitized mice received OVA-pulsed WT or CD80/CD86-/- DCs without OVA aerosol to address the role of costimulation during challenge. RESULTS: WT DCs induced the proliferation and effector TH2 differentiation of naive OVA-specific T cells, whereas CD80/CD86-/- DCs induced only proliferation. Not surprisingly, WT DCs but not CD80/CD86-/- DCs induced sensitization to OVA in naive mice. In contrast, in OVA-sensitized mice intratracheal injection of CD80/CD86-/- OVA-pulsed DCs led to eosinophilic airway inflammation, goblet cell hyperplasia, and effector TH2 cytokine production that was not different from that seen after injection with WT OVA-DCs, even when the inducible costimulator ICOS was blocked or cytotoxic T lymphocyte-associated antigen 4 immunoglobulin was given. CONCLUSION: CD80/CD86 costimulation on DCs is only necessary during priming of naive T cells into TH2 cells but not during restimulation of previously primed TH2 cells in the challenge phase.     

Characterization of Marek's disease herpesvirus-specific cytotoxic T lymphocytes in chickens inoculated with a non-oncogenic vaccine strain of MDV.

The chemoattractant effect of soluble protein antigens for B cells from immunized mice was examined. Mice were immunized either via the footpad with ovalbumin (OVA) in complete Freund's adjuvant (CFA) or with CFA alone; or intraperitoneally with OVA incorporated in immune-stimulating complexes (OVA-ISCOM) or with saline. After 8-14 days B cells were purified from the spleens or the draining popliteal nodes and tested in vitro for locomotor responses to antigen using polarization (shape-change) and filter assays. Cells obtained by both routes of immunization, but not cells from control mice, gave locomotor responses to OVA. Responses were seen in B cells directly after preparation (5-8% of cells responding) but were enhanced if the cells were cultured overnight in the presence of interleukin-4 (IL-4) before testing (10-12% of cells responding). Checkerboard filter assays suggested that the response to OVA was chemotactic. The response was antigen specific since cells from OVA-immunized mice did not respond to bovine serum albumin (BSA), and cells from BSA-immunized mice responded to BSA but not to OVA. The response to OVA was inhibited by preincubation of OVA with anti-OVA but not with anti-BSA. Many of the cells that polarized in response to antigen were larger than any B cells found in control populations suggesting that the responsive cells are those that had been stimulated to enter cell cycle following immunization.