An MDCK Cell Culture-Derived Formalin-Inactivated Influenza Virus Whole-Virion Vaccine from an Influenza Virus Library Confers Cross-Protective Immunity by Intranasal Administration in Mice

It is currently impossible to predict the next pandemic influenza virus strain. We have thus established a library of influenza viruses of all hemagglutinin and neuraminidase subtypes and their genes. In this article, we examine the applicability of a rapid production model for the preparation of vaccines against emerging pandemic influenza viruses. This procedure utilizes the influenza virus library, cell culture-based vaccine production, and intranasal administration to induce a cross-protective immune response. First, an influenza virus reassortant from the library, A/duck/Hokkaido/Vac-3/2007 (H5N1), was passaged 22 times (P22) in Madin-Darby canine kidney (MDCK) cells. The P22 virus had a titer of >2 ×10⁸ PFU/ml, which was 40 times that of the original strain, with 4 point mutations, which altered amino acids in the deduced protein sequences encoded by the PB2 and PA genes. We then produced a formalin-inactivated whole-virion vaccine from the MDCK cell-cultured A/duck/Hokkaido/Vac-3/2007 (H5N1) P22 virus. Intranasal immunization of mice with this vaccine protected them against challenges with lethal influenza viruses of homologous and heterologous subtypes. We further demonstrated that intranasal immunization with the vaccine induced cross-reactive neutralizing antibody responses against the homotypic H5N1 influenza virus and its antigenic variants and cross-reactive cell-mediated immune responses to the homologous virus, its variants within a subtype, and even an influenza virus of a different subtype. These results indicate that a rapid model for emergency vaccine production may be effective for producing the next generation of pandemic influenza virus vaccines.     

不同佐剂的复合黏膜疫苗鼻内免疫小鼠抗弓形虫感染的保护作用

目的比较IFN-γ和蜂胶作为佐剂鼻内免疫小鼠抗弓形虫攻击的能力,探索两种佐剂联合应用的效果。方法将5-6周龄雌性BALB／c小鼠60只随机分为4个组,每组15只,分别用20雌可溶性速殖子抗原（STAg）、20μg STAg＋40μg蜂胶、20μgSTAg＋1000U IFN-γ或20μgSTAg＋40μg蜂胶＋1000UIFN-γ鼻内免疫小鼠2次．间隔14d。末次免疫后第10天,用RH株弓形虫速殖子4×10^4个／只灌胃攻击,逐日观察小鼠存活情况。攻击后第43天处死全部存活小鼠,计算胸腺、脾指数,计数脑、肝组织速殖子。结果STAg＋IFN-γ组、STAg＋蜂胶＋IFN-γ组胸腺、脾指数显著高于STAg组（P〈0．05）;组织内速殖子虫荷显著降低（P〈0．01）,STAg＋IFN-γ组小鼠脑、肝组织减虫率分别为57．00％和79．06％;STAg＋蜂胶＋IFN-γ组小鼠脑、肝减虫率分别为68．30％和79．06％。STAg＋蜂胶组小鼠胸腺、脾指数有升高趋势,组织内速殖子虫荷降低,但与STAg组比较差异无统计学意义。结论在抗弓形虫感染中,IFN-γ、蜂胶＋IFN-γ的佐剂效果优于蜂胶,IFN-γ、蜂胶＋IFN-γ辅助STAg显著提高小鼠胸腺、脾比重,增强机体免疫能力,有效抵抗弓形虫的感染攻击,脑、肝组织速殖子虫荷显著减少。     

Comparison of Intranasal and Intramuscular Immunization against Human Immunodeficiency Virus Type 1 with a DNA-Monophosphoryl Lipid A Adjuvant Vaccine

We compared immune responses to intranasal and intramuscular DNA vaccinations against human immunodeficiency virus type 1 with monophosphoryl lipid A (MPL) used as an adjuvant. Both routes of vaccination resulted in similar levels of cell-mediated immunity, but the intestinal secretory immunoglobulin A response was higher following intranasal immunization than after intramuscular immunization. MPL demonstrated its adjuvanticity in vaccination by both routes.     

Immunity to Influenza in Ferrets X. Intranasal Immunization of Ferrets with Inactivated Influenza A Virus Vaccines

The response of ferrets after intranasal inoculation of inactivated A/Hong Kong/68 (H3N2) influenza virus vaccines is reported. Normal ferrets given either saline vaccine in drops or freeze-dried vaccine in an aerosol intranasally did not produce detectable serum or nasal hemagglutination inhibiting antibody and were found to be completely susceptible to challenge infection with A/Hong Kong/68 virus. Intranasal saline vaccine did not produce an additive effect on the response of ferrets simultaneously given the same vaccine intramuscularly with adjuvant. Ferrets primed by previous infection with A/PR/8/34 (H0N1) influenza virus, however, responded to intranasal immunization with saline A/Hong Kong/68 virus vaccine and produced serum and nasal antibody. These animals were found to be partially resistant to challenge infection, in contrast to similar animals given saline vaccine intramuscularly which were completely resistant to challenge infection. Primed ferrets did not respond after immunization with the freeze-dried aerosol vaccine, but this may have been due to a failure of the aerosol to be inhaled satisfactorily.     

Induction of Mucosal B-Cell Memory by Intranasal Immunization of Mice with Respiratory Syncytial Virus

The capacity of live or inactivated respiratory syncytial virus (RSV) to induce B-cell memory in respiratory-associated lymphoid tissues of mice was examined. Eight weeks after primary inoculation with either live or inactivated RSV, adult BALB/c mice were challenged with 4 × 10⁵ PFU of RSV. Protection from viral shedding and mucosal production of RSV-specific antibodies were examined at various time points after challenge. We found that primary immunization with live, but not inactivated, RSV induced complete and durable protection upon challenge within the upper and lower respiratory tract. Also, primary immunization with live, but not inactivated, RSV enhanced the production of mucosal RSV-specific immunoglobulin A (IgA) upon challenge. Secondary mucosal IgA responses were characterized by (i) the early production of mucosal IgA by B cells that reside in organized nasal-associated lymphoid tissues, cervical lymph nodes, and bronchial lymph nodes, and (ii) the subsequent production of RSV-specific IgA by mucosal effector tissues, such as the tracheal lamina propria and lung. These findings suggest that primary infection of mice with live RSV might induce mucosal IgA-committed memory B cells. A greater understanding of the characteristics of RSA-specific mucosal memory B cells may facilitate the development of an RSV vaccine.     

Oral Fluids as a Live-Animal Sample Source for Evaluating Cross-Reactivity and Cross-Protection following Intranasal Influenza A Virus Vaccination in Pigs

In North American swine, there are numerous antigenically distinct H1 influenza A virus (IAV) variants currently circulating, making vaccine development difficult due to the inability to formulate a vaccine that provides broad cross-protection. Experimentally, live-attenuated influenza virus (LAIV) vaccines demonstrate increased cross-protection compared to inactivated vaccines. However, there is no standardized assay to predict cross-protection following LAIV vaccination. Hemagglutination-inhibiting (HI) antibody in serum is the gold standard correlate of protection following IAV vaccination. LAIV vaccination does not induce a robust serum HI antibody titer; however, a local mucosal antibody response is elicited. Thus, a live-animal sample source that could be used to evaluate LAIV immunogenicity and cross-protection is needed. Here, we evaluated the use of oral fluids (OF) and nasal wash (NW) collected after IAV inoculation as a live-animal sample source in an enzyme-linked immunosorbent assay (ELISA) to predict cross-protection in comparison to traditional serology. Both live-virus exposure and LAIV vaccination provided heterologous protection, though protection was greatest against more closely phylogenetically related viruses. IAV-specific IgA was detected in NW and OF samples and was cross-reactive to representative IAV from each H1 cluster. Endpoint titers of cross-reactive IgA in OF from pigs exposed to live virus was associated with heterologous protection. While LAIV vaccination provided significant protection, LAIV immunogenicity was reduced compared to live-virus exposure. These data suggest that OF from pigs inoculated with wild-type IAV, with surface genes that match the LAIV seed strain, could be used in an ELISA to assess cross-protection and the antigenic relatedness of circulating and emerging IAV in swine.     

Intranasal Immunization of Mice with Influenza Vaccine in Combination with the Adjuvant LT-R72 Induces Potent Mucosal and Serum Immunity Which Is Stronger than That with Traditional Intramuscular Immunization

Immunization of mice by the intranasal route with influenza virus hemagglutinin in combination with the mutant Escherichia coli heat-labile enterotoxin R72 (LT-R72) induced significantly enhanced serum and mucosal antibodies, surpassing, in most cases, responses achieved by traditional intramuscular immunization using inactivated split influenza vaccine. Furthermore, intranasal immunization with LT-R72 induced a potent serum immunoglobulin G2a response, indicating that this adjuvant has Th1 character.     

H9N2 Influenza Whole Inactivated Virus Combined with Polyethyleneimine Strongly Enhances Mucosal and Systemic Immunity after Intranasal Immunization in Mice

Influenza whole inactivated virus (WIV) is more immunogenic and induces protective antibody responses compared with other formulations, like split virus or subunit vaccines, after intranasal mucosal delivery. Polyethyleneimine (PEI), an organic polycation, is widely used as a reagent for gene transfection and DNA vaccine delivery. Although PEI recently has demonstrated potent mucosal adjuvant activity for viral subunit glycoprotein antigens, its immune activity with H9N2 WIV is not well demonstrated. Here, mice were immunized intranasally with H9N2 WIV combined with PEI, and the levels of local respiratory tract and systemic immune responses were measured. Compared to H9N2 WIV alone, antigen-specific IgA levels in the local nasal cavity, trachea, and lung, as well as levels of IgG and its subtypes (IgG1 and IgG2a) in the serum, were strongly enhanced with the combination. Similarly, the activation and proliferation of splenocytes were markedly increased. In addition, PEI is superior as an H9N2 WIV delivery system due to its ability to greatly increase the viral adhesion to mucosal epithelial cells and to enhance the cellular uptake and endosomal escape of antigens in dendritic cells (DCs) and further significantly activate DCs to mature. Taken together, these results provided more insights that PEI has potential as an adjuvant for H9N2 particle antigen intranasal vaccination.     

人乳头瘤病毒HPV6b重组减毒沙门菌粘膜免疫的效果测定

为观察人乳头瘤病毒 6b型 (HPV6b )的重组减毒沙门菌载体疫苗粘膜免疫小鼠的免疫效果及探讨研制治疗尖锐湿疣的治疗性粘膜疫苗的机制 ,我们用构建的HPV6b重组减毒沙门菌粘膜免疫BALB/c小鼠 ,检测了阴道冲洗液中特异的SIgA、血清中IgG、T淋巴细胞增殖以及载体疫苗在机体内的稳定性。结果表明 ,粘膜免疫后 ,实验组与对照组相比较 ,阴道冲洗液中抗HPV6bL1的SIgA差异显著 ,实验组血清中抗HPV6bL1IgG水平低 ,T淋巴细胞增殖明显 ,疫苗在小鼠体内持续存在4 0d以上。研究结果提示我们所构建的重组减毒沙门菌粘膜免疫小鼠后 ,阴道粘膜局部能分泌特异的抗人乳头瘤病毒HPV6bSIgA ,也能激发细胞免疫 ,且此疫苗在小鼠体内能稳定存在。     

Vitamin Supplementation at the Time of Immunization with a Cold-Adapted Influenza Virus Vaccine Corrects Poor Mucosal Antibody Responses in Mice Deficient for Vitamins A and D

Vitamin A and D deficiencies and insufficiencies are prevalent worldwide in developed and developing countries. Vitamin metabolites are functionally intertwined in that they are high-affinity ligands for related receptors of the nuclear receptor superfamily. The effects of vitamin A deficiencies (VAD) on antibody responses to respiratory virus vaccines have already been demonstrated. Of particular concern was the reduction in IgA, a first line of defense against pathogens in the respiratory tract. Here, we describe the individual and combined effects of vitamin A and D deficiencies in mice immunized with an attenuated influenza virus vaccine. Relative to VAD, vitamin D deficiency (VDD) had a limited effect, but double deficiencies for vitamins A and D (VAD+VDD) further reduced antibody responses in the respiratory tract. The administration of supplemental vitamins A and D to VAD+VDD mice at the time of vaccination restored responses in a dose-dependent manner. Results suggest that vitamin supplementation programs may be beneficial in a clinical setting to promote healthy immune responses to respiratory virus vaccines in vitamin-deficient individuals.     

Long-Term Immunogenicity of an Inactivated Split-Virion 2009 Pandemic Influenza A H1N1 Virus Vaccine with or without Aluminum Adjuvant in Mice

In 2009, a global epidemic of influenza A(H1N1) virus caused the death of tens of thousands of people. Vaccination is the most effective means of controlling an epidemic of influenza and reducing the mortality rate. In this study, the long-term immunogenicity of influenza A/California/7/2009 (H1N1) split vaccine was observed as long as 15 months (450 days) after immunization in a mouse model. Female BALB/c mice were immunized intraperitoneally with different doses of aluminum-adjuvanted vaccine. The mice were challenged with a lethal dose (10× 50% lethal dose [LD₅₀]) of homologous virus 450 days after immunization. The results showed that the supplemented aluminum adjuvant not only effectively enhanced the protective effect of the vaccine but also reduced the immunizing dose of the vaccine. In addition, the aluminum adjuvant enhanced the IgG antibody level of mice immunized with the H1N1 split vaccine. The IgG level was correlated to the survival rate of the mice. Aluminum-adjuvanted inactivated split-virion 2009 pandemic influenza A H1N1 vaccine has good immunogenicity and provided long-term protection against lethal influenza virus challenge in mice.     

Intranasal Administration of Retinyl Palmitate with a Respiratory Virus Vaccine Corrects Impaired Mucosal IgA Response in the Vitamin A-Deficient Host

Our previous studies showed that intranasal vaccination of vitamin A-deficient (VAD) mice failed to induce normal levels of upper respiratory tract IgA, a first line of defense against respiratory virus infection. Here we demonstrate that the impaired responses in VAD animals are corrected by a single intranasal application of retinyl palmitate with the vaccine. Results encourage the clinical testing of intranasal vitamin A supplements to improve protection against respiratory viral disease in VAD populations.     

Effects of the Nature of Adjuvant and Site of Parenteral Immunization on the Serum and Mucosal Immune Responses Induced by a Nasal Boost with a Vaccine Alone

Outbred OF1 mice were immunized subcutaneously with flu vaccine, either in the neck or in the lumbar region (back), in combination with adjuvants inducing either a Th1- or a Th2-type response, referred to as adjuvants A1 and A2, respectively. After two parenteral immunizations, the mice were boosted intranasally with nonadjuvanted vaccine. The serum response was analyzed after each immunization by measuring specific immunoglobulin A (IgA), IgG1, and IgG2a antibody levels, while the local response (same isotypes) was measured in the salivary glands after the mucosal boost by ELISPOTs. We observed that systemic priming at any of the two sites with a Th2 rather than a Th1 adjuvant dramatically enhanced the mucosal IgG1 and IgA responses following a mucosal boost with unadjuvanted vaccine. In addition, as judged by the IgG2a/IgG1 ratios and serum IgA levels, immunization of mice in the back induced a rise in Th2 response compared to neck immunization with adjuvant A1. In contrast, such back immunization with adjuvant A2 reversed the Th1-Th2 balance in favor of the Th1 response compared to neck immunization. Similar differences were observed in mucosal antibody levels according to the site of priming with one given adjuvant; priming in the back with adjuvant A1 increased the mucosal IgA and IgG1 responses compared to neck priming, while the local IgG2a levels were decreased. The reverse was true for adjuvant A2. Back versus neck priming with this latter adjuvant decreased the mucosal IgG1 response, while local IgG2a levels were increased. The different lymphatic drainages of the two sites of parenteral immunization may explain these differences, due to the targeting of particular lymphoid inductive sites. Some of these sites may represent crossroads between systemic and mucosal immunity.     

Characteristics of Cytotoxic T Lymphocytes Directed to Influenza Virus Haemagglutinin Elicited by Immunization with Muramyldipeptide-Influenza Liposome Vaccine

We examined the characterization of the antiviral T lymphocytes elicited by immunization with a novel liposome vaccine (MDP-virosome) constructed with synthetic muramyldipeptide:[6-0-(2-tetradecylhexadecanoyl)-N-acetylmuramyl-L-alanyl-D-isoglutamine], cholesterol, influenza virus haemagglutinin and neuraminidase. The haemagglutinin glycoprotein first appeared to induce a significant subtypespecific cytotoxic activity through its arrangement on the inner and outer surfaces of the MDP-virosome. Splenocytes of BALB/c mice immunized with the virosome vaccine containing H3 haemagglutinin and N2 neuraminidase from human Hong Kong virus markedly lysed H3N2 virusinfected target cells, but not those infected with virus possessing a different subtype such as H1N1 surface antigens. Exposure of these splenic lymphocytes to virus antigen in vitro further enhanced their cytotoxic activity. The cytotoxic lymphocytes generated by the MDP-virosome vaccine expressed Thy 1 and CD4 antigens on their cell surface, and these activities were restricted by class II histocompatibility gene products. The marked reduction of pulmonary virus litres in infected mice caused by transferred immune spleen cells suggested that the MDP-virosome vaccination is able to protect against influenza virus infection through enhanced cellular immune responses.     

Immunogenicity of a Monovalent Pandemic Influenza A H1N1 Virus Vaccine with or without Prior Seasonal Influenza Vaccine Administration

The immunogenicity of pandemic influenza A H1N1 virus (A/H1pdm) vaccine might be modified by prior seasonal trivalent influenza vaccine (sTIV) administration. We conducted a retrospective analysis of immunogenicity of 243 health care workers (number of sTIV-positive [sTIV⁺] subjects, 216; number of sTIV⁻ subjects, 27) by hemagglutination inhibition. There was no significant difference in the ratios of antibody titers of ≥40 (41.2% versus 48.1%; P = 0.49) and fold increases in geometric mean titer (3.8 versus 4.5; P = 0.37). sTIV injected 7 to 10 days prior to A/H1pdm vaccine administration did not interfere with the immunogenicity of the latter.     

Humoral and Cellular Response in Humans After Immunization with Influenza Vaccine

The peripheral blood lymphocyte response and hemagglutination inhibition antibody titers were measured in nine adults before and after immunization with a killed split influenza virus vaccine. Cord blood lymphocytes were tested with the influenza antigen to exclude a nonspecific mitogenic effect. All of the subjects demonstrated preexisting antibody titers and antigen recognition by lymphocytes prior to immunization. The in vitro lymphocyte response after vaccination parallels the humoral antibody response to influenza antigen.     

Cross-Protection in Mice After Immunization with H2N2, H3N2, and Heq2Neq2 Influenza Virus Strains

Mice were vaccinated with the influenza viruses A/Japan/57 (H2N2), A/Hong Kong/68 (H3N2), and A/Equi/Miami/63 (Heq2Neq2) and the hemagglutinin and neuraminidase recombinants derived from these viruses. After infection with the parent viruses, protection was compared with serological findings. It was found that influenza vaccine protects not only against infection with a strain identical or closely related to the vaccine strain, but against heterologous strains as well. Vaccination with Hong Kong/68 and its neuraminidase recombinant resulted in a heterologous neuraminidase inhibition titer against Japan/57 and in a protection against infection with Japan/57. By contrast, after vaccination with Japan/57 and its neuraminidase recombinant, no relevant heterologous neuraminidase inhibition titer against Hong Kong/68 was observed, whereas a protection against infection with Hong Kong/68 did exist. A cross-protection between Hong Kong/68 and Miami/63, but no relationship in the hemagglutination or neuraminidase inhibition tests, was established in the preinfection sera. A one-way antigenic relationship between these viruses was confirmed by the rise of hemagglutinin or neuraminidase antibodies against Hong Kong/68 in the postinfection sera. No cross-protection or serological relationship existed between Miami/63 and Japan/57. Besides the hemagglutinin and neuraminidase, a third factor, the “mouse-protecting antigen,” was considered to contribute to the protection obtained. According to the protection observed, the mouse-protecting antigen of Hong Kong/68 virus is related to that of Japan/57 as well as Miami/63 virus. The mouse-protecting antigens of both Japan/57 and Miami/63 are related to that of Hong Kong/68.     

Induction of Local Secretory IgA and Multifunctional CD4+ T‐helper Cells Following Intranasal Immunization with a H5N1 Whole Inactivated Influenza Virus Vaccine in BALB/c Mice

Avian influenza subunit vaccines have been shown to be poorly immunogenic, leading to the re‐evaluation of the immunogenic and dose‐sparing potential of whole virus vaccines. In this study, we investigated the immune responses after one or two doses of intramuscular or intranasal whole inactivated influenza H5N1 virus vaccine in BALB/c mice. Serum samples and nasal washings were collected weekly post‐vaccination and analysed using enzyme‐linked immunosorbent assay (ELISA). Sera were also analysed by the haemagglutination inhibition (HI) assay. Antibody‐secreting cells were measured in lymphocytes from spleen and bone marrow via enzyme‐linked immunospot (ELISPOT). Splenocytes were stimulated in vitro, and T‐helper profiles were measured through multiplex bead assay in the supernatants, or intracellularly by multiparametric flow cytometry. Both vaccine routes induced high HI titres following the second immunization (intramuscular = 370, intranasal = 230). Moreover, the intramuscular group showed significantly higher levels of serum IgG (P < 0.01), IgG1 (P < 0.01) and IgG2a (P < 0.01) following the second vaccine dose, while the intranasal group exhibited significantly higher levels of serum IgA (P < 0.05) and local IgA (P < 0.01) in the nasal washings. Also, IgA antibody‐secreting cells were found in significantly higher numbers in the intranasal group in both the spleen (P < 0.01) and the bone marrow (P < 0.01). Moreover, Th1 (TNF‐α, IL‐2, IFN‐γ) and Th2 (IL‐4, IL‐5, IL‐10) cytokines were expressed by both groups, yet only the intranasal group expressed the Th17 marker IL‐17. As the intranasal vaccines induce local IgA and are easily administered, we suggest the intranasally administered whole virus vaccine as a promising candidate for a pandemic H5N1 vaccine.     

双价志贺菌苗滴鼻免疫对小鼠NALT、GALT和脾淋巴细胞的影响

本文是探讨滴鼻免疫对NALT、GALT和脾淋巴细胞中特异性抗体分泌细胞及淋巴细胞表型变化的影响。将Balb/c小鼠随机分为 3组 ,每组 2 0只。FSM 2 117或FS 5 416 4× 10 7CFU/只经滴鼻途径免疫小鼠 ,间隔 2周 ,3次免疫后 7d活杀 ,分离NALT、鼻通道、脾、小肠PP及MLN淋巴细胞 ,采用BA ELISPOT法检测其中特异性抗福氏、宋内LPSIgA和IgG分泌细胞 ;采用流式细胞术检测其淋巴细胞表型的变化。结果是两株菌苗经鼻内免疫都诱发了NALT、NP、GALT内 (PP、MLN、LPL )以及代表系统免疫反应的脾淋巴细胞中特异性抗福氏、宋内LPSIgA、IgG ASC的显著增加 (P <0 0 1) ;NALT、NP和PP淋巴细胞中CD3+T细胞显著增加 ,其中以CD4+T细胞增加为主 ;FSM 2 117免疫组的脾细胞中B2 2 0 +细胞显著增加 (P <0 0 1) ,而FS 5 416免疫组的脾细胞中CD3+T细胞显著增加 (P <0 0 1)。说明两株菌苗经鼻粘膜免疫均可诱导鼻粘膜局部、GALT及系统免疫反应的发生 ,是一个安全有效的免疫途径