炭疽活疫苗家兔免疫力与血清抗芽胞IgG关系的研究

炭疽疫苗是预防炭疽流行和炭疽生物恐怖的重要手段。已有动物实验表明,炭疽活疫苗的保护力优于以保护性抗原为主要成份的无细胞疫苗,但两类现行疫苗都有待重新评价和改进。炭疽疫苗的效力必须用适当的实验室方法进行检测与分析才能了解其性质和细节。试验中力图探寻炭疽活疫苗家兔免疫力与血清抗芽胞抗体水平的关系。用“皮上划痕人用炭疽活疫苗”免疫家兔,以特定制备的炭疽芽胞抗原用ELISA法检测血清抗炭疽芽胞IgG抗体水平,并用强毒炭疽杆菌攻击进行效力试验。免疫家兔血清几何平均抗芽胞IgG滴度在免疫后一个月内持续升高,14d达到206,28d时达到776,这时其抵抗20MLD毒菌攻击的保护率为80％,符合中国生物制品规程要求的保护力。一个月后抗体水平开始下降,42d时滴度降至223。实验所揭示的炭疽减毒活疫苗诱导的家兔抗芽胞IgG抗体与抗炭疽保护力之间的关系,既为评价现行疫苗提供了资料,也为研制新型疫苗建立了参考性指标。     

Enterobacterial 38-kDa outer membrane protein is an age-dependent molecular marker of innate immunity and immunoglobulin deficiency as results from its reactivity with IgG and IgA antibody

In earlier studies on an animal model we observed protective properties of outer membrane proteins (OMPs) of Shigella, Hafnia, and Escherichia coli strains. In order to investigate human sera for reactivity with OMPs we subjected these proteins to immunoblotting with umbilical cord plasma and sera from children and adults. The IgG and IgA antibodies interacted primarily with a 38-kDa protein, in similar way for several enterobacterial strains, but different for Pseudomonas aeruginosa. This observation prompted us to determine the reactivity with the purified 38-kDa OMP in the sera of several groups of children. The reactivity of the protein from Shigella flexneri serotype 3a with sera in ELISA was age dependent, increasing from low reactivity in infants to the adult antibody level. The IgG and IgA antibody specific response thus revealed the normal pattern of immunity. The level of IgA and IgG antibody was significantly low in child patients with IgA and/or IgG immunoglobulin deficiencies, but was at the healthy control level in children with recurrent respiratory tract inflammation. These data correlated with total IgA and IgG levels in immunoglobulin-deficient children. The results indicate that this protein may serve as an immunodiagnostic marker, but also as an antigen carrier in vaccines.     

Experimentally determined safety and immunological activity of vaccine based on antigens isolated from Pseudomonas aeruginosa in medium K-4

The safety and immunological activity of P. aeruginosa vaccine were experimentally evaluated. The vaccine was prepared on the basis of the antigens of P. aeruginosa extracellular slime which was accumulated in medium K-4, obtained with the use of original technology. The immunization of animals with P. aeruginosa vaccine induced the synthesis of antibodies. The introduction of the vaccine in 2 or 3 injections resulted in a high level of antibody formation, differing with the use of various strains. Hyperimmune sera, obtained by the multiple immunization of rabbits with P. aeruginosa vaccine, ensured high protection of mice from P. aeruginosa infection. The vaccine proved to be safe when evaluated in experiments of acute and chronic toxicity, made on laboratory animals.     

Mucosal and systemic immune responses of mice to tetanus toxoid coadministered nasally with AFCo1

Mucosal immune responses are an early and important line of defense against pathogens. The current understanding of the mucosal immune system allows us to consider the use of nasal immunization for induction of antigen-specific immune responses at the mucosal surface and the systemic compartment. Mucosal adjuvants are key for developing novel mucosal vaccines and represent 1 approach to improving mucosal and systemic immunity. However, few mucosal vaccine adjuvants are currently approved for human use. Neisseria meningitidis B proteoliposome-derived cochleate (AFCo1 - Adjuvant Finlay Cochleate 1) has been demonstrated to be a potent mucosal adjuvant. The present work demonstrates that intranasal immunization of 3 doses of tetanus toxoid (TT) coadministered with AFCo1 in mice promotes high systemic and mucosal responses. The anti-TT IgG serum titers and the mucosal anti-TT IgA in saliva and vaginal wash were significantly higher than TT alone. The analysis of antibody subclasses showed that intranasal administration of AFCo1 + TT induced not only IgG1 but also IgG2a anti-TT antibodies at levels comparable to those obtained with TT vaccine (vax-TET). These data support the fact that AFCo1 is a potent mucosal adjuvant in nasal immunization to a coadministered protein antigen.     

Role of group A streptococcal IgG Fc-receptor in induction of anti-IgG by immunization in the rabbit

Abstract Previous work has demonstrated that streptococcal IgG Fc-receptors (FcR) may trigger production of anti-IgG after immunization of rabbits with group A streptococci. This effect seemed dependent on in vitro binding of IgG, derived from the growth medium, to the vaccine strains. In the experiments presented here, IgG was eluted from streptococcal strains to be used for immunization of rabbits by 1 M KSCN and washing, a treatment which did not affect the capacity of the strains to bind newly added IgG. Using two IgG FcR-positive group A streptococcal strains (M-types 1 and 22) for intravenous immunization, anti-IgG was found in the sera of 26 out of 28 rabbits, examined 8 weeks after immunization. In contrast, anti-IgG was not induced in 16 rabbits receiving either group A, type T27 or group B, type Ia streptococci both of which lack surface FcR activity. Finally, immunization with purified streptococcal IgG FcR (0.35 mg, given subcutaneously combined with Freund's complete adjuvant and two weeks later intraconjunctivally without adjuvant) also induced anti-IgG. In all rabbits, anti-human rather than anti-rabbit IgG was detected. It is proposed that in vivo interaction between the bacterial FcR and rabbit IgG, resulting in conformation changes in IgG, is a prerequisite for the induction of anti-IgG. Thus, streptococcal triggering of anti-IgG, ascribable to IgG Fc-receptor activity and not requiring presence of foreign IgG, has been demonstrated in the rabbit.     

Role of group A streptococcal IgG Fc-receptor in induction of anti-IgG by immunization in the rabbit

Previous work has demonstrated that streptococcal IgG Fc-receptors (FcR) may trigger production of anti-IgG after immunization of rabbits with group A streptococci. This effect seemed dependent on in vitro binding of IgG, derived from the growth medium, to the vaccine strains. In the experiments presented here, IgG was eluted from streptococcal strains to be used for immunization of rabbits by 1 M KSCN and washing, a treatment which did not affect the capacity of the strains to bind newly added IgG. Using two IgG FcR-positive group A streptococcal strains (M-types 1 and 22) for intravenous immunization, anti-IgG was found in the sera of 26 out of 28 rabbits, examined 8 weeks after immunization. In contrast, anti-IgG was not induced in 16 rabbits receiving either group A, type T27 or group B, type Ia streptococci both of which lack surface FcR activity. Finally, immunization with purified streptococcal IgG FcR (0.35 mg, given subcutaneously combined with Freund's complete adjuvant and two weeks later intraconjunctivally without adjuvant) also induced anti-IgG. In all rabbits, anti-human rather than anti-rabbit IgG was detected. It is proposed that in vivo interaction between the bacterial FcR and rabbit IgG, resulting in conformation changes in IgG, is a prerequisite for the induction of anti-IgG. Thus, streptococcal triggering of anti-IgG, ascribable to IgG Fc-receptor activity and not requiring presence of foreign IgG, has been demonstrated in the rabbit.     

The immunogenicity of the liposome-associated outer membrane proteins (OMPs) of <Emphasis Type="Italic">Moraxella catarrhalis</Emphasis>

The outer membrane proteins (OMPs) are the most immunogenic and attractive of the Moraxella catarrhalis vaccine antigens that may induce the protective immune response. The aim of this study was to determine the effectiveness of two types of OMP-associated phosphatidylcholine (PC) liposomal formulations (OMPs-PC, PC-OMPs) and of Zwittergent-based proteomicelles (OMPs-Z) in potentiating an anti-OMP systemic immune response in mice. The immunogenicities of the above preparations were evaluated by assessing serum anti-OMP IgG and IgA reactivity in the post-immunized mouse antisera using ELISA and Western blotting. Additionally, the cross-reactivity of the most effective anti-OMP response was determined using heterologous sera from both humans and mice. Both the proteoliposomes and the proteomicelles showed high immunogenic properties and did not elicit any distinct quantitative differences in the antibody titer or qualitative differences in the pattern of the mouse antisera. The post-immunized mouse antisera predominantly recognized a ∼60-kDa OMP of M. catarrhalis. That protein was also found to be a highly cross-reactive antigen interacting with a panel of pooled mouse antisera produced by immunization either with whole cells or the purified OMPs of heterologous M. catarrhalis strains. Furthermore, normal sera collected from healthy children were found to be preferentially reactive with the 60-kDa OMP. The serum-specific IgG, IgA and IgM were respectively detected via immunoblotting in 90%, 85% and 30% of heterologous human sera. This similar immunogenic effectiveness of both OMP-associated liposomal formulations could contribute to the practical use of such formulations in the future in human vaccination. Moreover, the highly cross-reactive 60-kDa OMP seems to be an important antigenic marker of M. catarrhalis, and, as it is responsible for the induction of an antibody-mediated and long-lasting immune response, studying it may partially aid us in understanding the relatively low degree of pathogenicity of the bacterium in immunocompetent individuals.     

Heterogeneous antibody response to polyvalent melanoma vaccines in syngeneic mice

In this study, a human melanoma vaccine induced antibody responses in mice that varied significantly from animal to animal. BALB/c mice were immunized to a xenogenic human polyvalent melanoma vaccine that has been used in phase II clinical trials in over 600 patients. Mice were bled biweekly for up to 6 weeks to measure antibody responses. IgG antibody responses to the melanoma vaccine components were detectable within 2 weeks but were much stronger at 4 and 6 weeks. When the pooled sera were further analyzed by Western blot, a complex pattern of antigens was detected. When individual sera from identically immunized mice were assayed by Western blot, a consistent, reproducible pattern of antigen recognition was not seen. Rather, we found significantly different antibody responses among the mice. Both the intensity of antibody responses and the pattern of antigens recognized varied from animal to animal. Although there appeared to be immunodominant antigens that produced antibody responses in most mice, no single antigen induced antibody responses in all mice. These results demonstrate that polyvalent vaccines induce heterogeneous antibody responses in mice treated identically. Analysis of the response of selected melanoma patients immunized to the same vaccine revealed similar antibody responses to the antigens in the melanoma vaccine. Heterogeneity may hamper interpretation of vaccine immunogenicity and relevant tumor antigens in humans.     

Pertussis toxin and cross-reactive antigens in dynamics of Bordetella pertussis cultivation

Cultures of Bordetella pertussis from phases of exponential growth, retarded growth and from stationary phase were obtained during periodic dynamic cultivation. Preparations for intravenous immunization of rabbits were made from these cultures. Levels of IgG to pertussis toxin, cell walls preparations from 12 bacterial species, 4 organo-specific antigens, and 7 organospecific human antigens were measured in obtained sera. It was shown that higher levels of IgG to pertussis toxin were found in sera of rabbits immunized with cultures from exponential growth phase whereas decrease of this level in 8 times was observed in sera of rabbits immunized with cultures from retarded growth phase or end of stationary phase. After immunization with culture from exponential growth phase increase of IgG levels to cross-reactive antigens was not observed compared to levels of these antibodies in control sera obtained before immunization. After immunization with cultures from retarded growth phase or end of stationary phase increase of IgG levels to preparations of cell walls of Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Klebsiella pneumoniae, to denaturated DNA, elastin, and renal and liver microsomal fractions was detected compared to control sera. Described data can substantiate usefulness of obtaining the most specific diagnostic sera and test-systems using cultures of B. pertussis from the phase of exponential growth.     

金黄色葡萄球菌重组GapC蛋白的GAPDH活性及免疫原性分析

为研究金黄色葡萄球菌(Staphylococcus aureus)表面GapC蛋白的GAPDH活性、免疫原性及免疫保护作用, 应用PCR方法扩增出S. aureus的gapC基因, 插入到pQE-30载体相应位点, 构建重组质粒pQE/gapC。将其导入宿主菌E.coli M15(pREP4)后, IPTG诱导表达。重组蛋白纯化后进行GAPDH活性检测, 并与灭活全菌体分别免疫健康家兔。然后, 应用ELISA方法检测血清中IgG抗体水平及IFN-g、IL-4细胞因子浓度, 并用1.0×108CFU/mL S. aureus菌株Wood46对免疫家兔攻毒。SDS-PAGE结果显示, GapC蛋白在E. coli M15(pREP4)中获得表达; 经GAPDH活性检测及Western Blot检测, 重组蛋白具有较高的GAPDH活性和抗原特异性; 经ELISA检测, GapC蛋白及全菌体组兔血清中IgG抗体水平迅速升高, 并在加强免疫后第28天达到最高(1:64 000), 加强免疫后第14 d, 血清中细胞因子IFN-g和IL-4浓度与对照组相比, 显著升高(P<0.05), 而全菌体免疫组升高不明显(P>0.05); 攻毒结果为蛋白免疫组家兔获得一定的免疫保护(4/5)。以上结果表明, 表达的重组GapC蛋白具有GAPDH活性、较好的免疫原性及免疫保护力, 可作为深入研究S. aureus基因工程疫苗的良好靶向。     

Induction of high levels of epitope-specific antibodies by epitope/peptide candidate vaccines against human immunodeficiency virus type-1 (HIV-1)

To test the immunogenicity of GPGRAFY-epitope-based candidate vaccines, a peptide with four repetitive GPGRAFY epitopes, V3-P1 [C-(GPGRAFY)4], and a peptide (PND) of the principal neutralizing domain (V3 loop: amino acid 301-328: C-TRPNNNTRKSIRIQRGPGRAFYTIGKI) on gp120 were synthesized and covalently coupled to a carrier protein BSA. Immunization of BALB/c mice and New Zealand White Rabbits with these conjugate vaccines engendered strong antibody responses against the PND (mouse serum titer by 1:12,800-25,600; rabbit serum titer by 1:6,400-12,800). Interestingly, the V3-P1-BSA conjugates and the PND-BSA conjugates could induce high levels of GPGRAFY-epitope-specific antibodies in the mice and rabbits (mouse serum titer by 1:25,600; rabbit serum titer by 1:12,800-25,600), while a recombinant gp160 subunit vaccine induced a low level of GPGRAFY-epitope-specific antibodies (serum titer by 1:400-1,600 in mice and rabbits). To confirm the above results, GPGRAFY-epitope-specific antibodies were isolated from rabbit sera induced by V3-P1-BSA, PND-BSA conjugates and rgp160 vaccine. In fact, 23-38 and 13-22 microg epitope-specific antibodies per milliliter serum were isolated from rabbit sera induced by V3-P1-BSA and PND-BSA conjugate, respectively, while 1.34 microg epitope-specific antibodies per milliliter serum were identified in rabbit serum induced by rgp160 vaccine. In the control group, only 0.069 microg proteins per milliliter serum were found in pooled pre-immune serum (normal serum). These results from mouse and rabbit experiments indicate that epitope and peptide vaccines both induce high levels of GPGRAFY-epitope-specific antibodies in comparison with rgp160 subunit vaccine, suggesting that epitope/peptide vaccines may be a new strategy to induce protective activity.     

金黄色葡萄球菌重组GapC蛋白的GAPDH活性及免疫原性分析

为研究金黄色葡萄球菌(Staphylococcus aureus)表面GapC蛋白的GAPDH活性、免疫原性及免疫保护作用, 应用PCR方法扩增出S. aureus的gapC基因, 插入到pQE-30载体相应位点, 构建重组质粒pQE/gapC。将其导入宿主菌E.coli M15(pREP4)后, IPTG诱导表达。重组蛋白纯化后进行GAPDH活性检测, 并与灭活全菌体分别免疫健康家兔。然后, 应用ELISA方法检测血清中IgG抗体水平及IFN-g、IL-4细胞因子浓度, 并用1.0×108CFU/mL S. aureus菌株Wood46对免疫家兔攻毒。SDS-PAGE结果显示, GapC蛋白在E. coli M15(pREP4)中获得表达; 经GAPDH活性检测及Western Blot检测, 重组蛋白具有较高的GAPDH活性和抗原特异性; 经ELISA检测, GapC蛋白及全菌体组兔血清中IgG抗体水平迅速升高, 并在加强免疫后第28天达到最高(1:64 000), 加强免疫后第14 d, 血清中细胞因子IFN-g和IL-4浓度与对照组相比, 显著升高(P<0.05), 而全菌体免疫组升高不明显(P>0.05); 攻毒结果为蛋白免疫组家兔获得一定的免疫保护(4/5)。以上结果表明, 表达的重组GapC蛋白具有GAPDH活性、较好的免疫原性及免疫保护力, 可作为深入研究S. aureus基因工程疫苗的良好靶向。     

Vaccine with bacterium-like particles displaying HIV-1 gp120 trimer elicits specific mucosal responses and neutralizing antibodies in rhesus macaques

Preclinical studies have shown that the induction of secretory IgA (sIgA) in mucosa and neutralizing antibodies (NAbs) in sera is essential for designing vaccines that can effectively block the transmission of HIV-1. We previously showed that a vaccine consisting of bacterium-like particles (BLPs) displaying Protan-gp120AE-MTQ (PAM) could induce mucosal immune responses through intranasal (IN) immunization in mice and NAbs through intramuscular (IM) immunization in guinea pigs. Here, we evaluated the ability of this vaccine BLP-PAM to elicit HIV-1-specific mucosal and systemic immune responses through IN and IM immunization combination strategies in rhesus macaques. First, the morphology, antigenicity and epitope accessibility of the vaccine were analysed by transmission electron microscopy, bio-layer interferometry and ELISA. In BLP-PAM-immunized macaques, HIV-1-specific sIgA were rapidly induced through IN immunization in situ and distant mucosal sites, although the immune responses are relatively weak. Furthermore, the HIV-1-specific IgG and IgA antibody levels in mucosal secretions were enhanced and maintained, while production of serum NAbs against heterologous HIV-1 tier 1 and 2 pseudoviruses was elicited after IM boost. Additionally, situ mucosal responses and systemic T cell immune responses were improved by rAd2-gp120AE boost immunization via the IN and IM routes. These results suggested that BLP-based delivery in combination with the IN and IM immunization approach represents a potential vaccine strategy against HIV-1.     

人参多糖对新甲型H1N1流感病毒灭活疫苗的免疫增强作用

在流感灭活疫苗中添加佐剂可以提高疫苗的免疫原性,节约抗原用量。一些天然中草药多糖具有潜在的佐剂效应。本文探讨了人参多糖（ginseng polysaccharide,GPS）在新甲型H1N1流感病毒裂解型灭活疫苗中的佐剂效应。将不同剂量GPS与新甲型H1N1流感病毒灭活疫苗混合,共同免疫小鼠一次,通过检测免疫后在小鼠体内诱导产生的疫苗特异性IgM、IgG、IgG1和IgG2a抗体情况来评价GPS作为流感病毒灭活疫苗佐剂的免疫增强效果,并与不添加佐剂的疫苗和加有铝佐剂的疫苗的免疫效果作比较。结果显示,GPS与铝佐剂一样能显著提高和维持疫苗特异性IgG抗体滴度,同时提高IgM抗体水平,其中800μgGPS的佐剂效果最好。因此我们认为GPS可以作为流感病毒灭活疫苗的一种候选佐剂。     

HCV多表位抗原基因重组减毒口服活菌苗的研究

把丙型肝炎病毒(hepatitis C virus,HCV)复合多表位抗原基因PCX与β半乳糖苷酶基因(GZ)融合后,构建重组减毒鼠伤寒沙门氏菌口服活菌苗SL3261(pWR/PCX),免疫小鼠及家兔后,于第6周始可检测到低水平的抗GZPCX IgG(1∶200),至3月时最高滴度分别达1∶800及1∶25 600,均显著高于宿主菌SL3261组及空白对照组。在免疫小鼠的肠道灌洗液中可检测到抗GZPCX sIgA\.GZPCX抗原可促进免疫小鼠及家兔淋巴细胞增殖,诱发明显的迟发性超敏反应(DTH)。口服免疫后小鼠体重出现一过性下降,但未见其它明显的毒性作用,安全性较好。本研究从新的角度探讨了HCV复合多表位重组口服活菌苗的可行性,为HCV疫苗的研究提供新的实验依据。     

DNA vaccine of SARS-Cov S gene induces antibody response in mice

The spike (S) protein, a main surface antigen of SARS-coronavirus (SARS-CoV), is one of themost important antigen candidates for vaccine design. In the present study, three fragments of the truncated S protein were expressed in E. coli, and analyzed with pooled sera of convalescence phase of SARS patients. The full length S gene DNA vaccine was constructed and used to immunize BALB/c mice. The mouse serum IgG antibody against SARS-CoV was measured by ELISA with E. coli expressed truncated S protein or SARS-CoV lysate as diagnostic antigen. The results showed that all the three fragments of S protein expressed by E. coli was able to react with sera of SARS patients and the S gene DNA candidate vaccine could induce the production of specific IgG antibody against SARS-CoV efficiently in mice with seroconversion ratio of 75% after 3 times of immunization. These findings lay some foundations for further understanding the immunology of SARS-CoV and developing SARS vaccines.     

AIDS vaccination studies using an ex vivo feline immunodeficiency virus model: reevaluation of neutralizing antibody levels elicited by a protective and a nonprotective vaccine after removal of antisubstrate cell antibodies

In the feline immunodeficiency virus system, immunization with a fixed-infected-cell vaccine conferred protection against virulent homologous challenge but the immune effectors involved remained elusive. In particular, few or no neutralizing antibodies were detected in sera from vaccinated cats. Here we show that, when preadsorbed with selected feline cells, the same sera revealed clearly evident virus-neutralizing activity. Because high titers of neutralizing antibody in cell-adsorbed sera from 23 cats immunized with fixed-infected-cell or whole-inactivated-virus vaccines correlated with protection, it is likely that they were more important for protection than formerly realized. In vitro, the fixed-cell vaccine efficiently removed neutralizing antibody from immune sera while the whole-inactivated-virus vaccine was much less effective.     

炭疽灭活和裂解芽胞抗原免疫家兔后血清中的IgG抗体应答

炭疽杆菌芽胞在炭疽免疫中发挥基本作用。实验中以炭疽活芽胞疫苗为原形,建立了制备灭活和裂解炭疽芽胞的方法,研究了各种灭活和裂解炭疽芽胞疫苗不同浓度、不同剂次免疫家兔的抗芽胞和毒素IgG应答,总结分析了各种灭活和裂解炭疽芽胞疫苗用于新疫苗成分之一的可能性。甲醛灭活炭疽芽胞疫苗设芽胞浓度2.5×108剂量组、5×108剂量组、1×109剂量组,于0、4、8周时3次免疫。在3剂免疫后血清抗炭疽芽胞IgG水平持续升高,首次免疫后4、8、12周时家兔血清中抗芽胞IgG几何平均滴度可达到600～16000。裂解炭疽芽胞疫苗的制备和动物免疫中,只采取了2.5×108芽胞浓度,两剂免疫,免疫时间为0、4周。在首次免疫后4、8、12周时家兔血清中抗芽胞IgG几何平均滴度分别为362、776和388。各时间点采集的家兔血清未能测出或只测出极微量的抗炭疽毒素IgG。通过上述研究认为,以裂解炭疽芽胞抗原作为炭疽疫苗成分之一,其抗原性和免疫原性是适宜的;免疫剂量可以设定为2.5×108芽胞浓度上下;免疫次数可定为2剂间隔1个月。     

Immunopotentiation of outer membrane protein through anti-idiotype Pasteurella multocida vaccine in rabbits

Pasteurella multocida was isolated from cattle affected with haemorrhagic septicaemia and characterized on the basis of morphological, cultural and biochemical tests. Bacterial outer membrane proteins (OMPs) were extracted with 1% Sarkosyl method. P. multocida anti-idiotype vaccine prepared from OMPs (21.3 mg per 100 ml), was evaluated and compared with bacterin supplemented with 10% OMPs and plain alum-adsorbed bacterin in rabbit models. It was observed that OMPs-anti-idiotype vaccine induced high levels of antibody titres (geomean titres -GMT) detected using indirect haemagglutination (IHA) test. The OMPs anti-idiotype antibody titres of 168.9 GMT were obtained to 42.2 GMT in OMPs supplemented bacterin on 21 days post vaccination, while the plain bacterin had the least titre of 27.9 GMT. The OMPs-anti-idiotype vaccine provoked better immunogenic response in terms of highest GMT titres and long lasting effect in rabbits and 100% protection against the challenge with homologous strain of P. multocida,while 88% protection was obtained in rabbits, given OMPs supplemented bacterin.     

Antibodies to meningococcal H.8 (Lip) antigen fail to show bactericidal activity

Purified H.8 (Lip) antigen was coupled to tresyl-activated Sepharose 4B and used in affinity columns to purify anti-Lip antibodies from convalescent patient sera and from immune rabbit sera. Affinity-purified anti-Lip antibodies isolated from two convalescent patient sera contained 1000 and 1280 ELISA units of antibody and included antibodies of IgG, IgA, and IgM isotypes. An anti-Lip mouse monoclonal ascites (2-1-CA2) had 28,400 ELISA units of antibody. Bactericidal assays were performed using three different case strains of Neisseria meningitidis group B, namely 44/76, 8532, and 8047. Neither preparation of purified human anti-Lip antibodies had detectable bactericidal activity against strains 44/76 and 8532, but one of the two had a titer of 1:4 against strain 8047. Anti-Lip antibodies that were purified from immune rabbit serum and contained 1600 ELISA units of anti-Lip antibodies also failed to show detectable bactericidal activity. The rabbits were immunized with purified Lip antigen and showed specific antibody levels of 2000-2200 units by ELISA, but even the unfractionated sera had little or no bactericidal activity against the test strains. The high titer mouse monoclonal ascites had no bactericidal activity against the test strains. The poor bactericidal activity associated with monoclonal and polyclonal antibodies to the Lip antigen suggest that in spite of other attractive properties it may not be useful as a meningococcal vaccine.