Immune response to a hepatitis B DNA vaccine in Aotus monkeys: a comparison of vaccine formulation, route, and method of administration.

BACKGROUND: Attempts to optimize DNA vaccines in mice include using different routes of administration and different formulations. It may be more relevant to human use to carry such studies out in nonhuman primates. Here we compare different approaches to delivery of a DNA vaccine against the hepatitis B virus (HBV) in Aotus monkeys. MATERIALS AND METHODS: Thirty-two adult Aotus l. lemurinus monkeys divided into 8 groups of four were immunized with 400 microg of a DNA vaccine which encoded hepatitis B surface antigen (HBsAg). DNA in saline was administered by intradermal (ID) or intramuscular (IM) injection with needle and syringe, IM injection with the Biojector needleless injection system or combined ID (needle) and IM (Biojector). DNA formulated with cationic liposomes (CellFECTIN) was injected IM with needle or Biojector. DNA with added E. coli DNA (100 microg) was injected IM with the Biojector or ID. A ninth group of 4 monkeys was injected IM (needle) with Engerix-B, a commercial vaccine containing recombinant HBsAg (10 microg) adsorbed onto alum. Monkeys were boosted in an identical fashion to their prime at 8 weeks, but all received the protein vaccine (Engerix-B) at 16 weeks. Sera was assessed for antibodies against HBsAg (anti-HBs) by enzyme-linked imunosorbent assay (ELISA). RESULTS: The primary humoral response induced by IM delivery of the DNA vaccine was very poor. In most cases there was no detectable anti-HBs even after 2 DNA doses but the kinetics of the response to subsequent protein indicated that a memory B cell response had been induced. In contrast, following IM-administration of DNA using the Biojector, detectable anti-HBs were observed in 3 of 8 animals and evidence for immunological priming was apparent in an additional 4 of the 8 monkeys. ID injection of DNA vaccine in saline induced a potent antibody response which was augmented 6-fold by the addition of E. coli DNA. Combining ID and IM administration did not improve humoral immunity over ID injection alone. CONCLUSIONS: For immunization of primates with DNA vaccines, ID may be a preferable route to IM, although it is not clear whether the Aotus monkey is a relevant model for humans in this respect. Nevertheless, the use of the Biojector needleless injection system may improve responses with IM delivery of DNA vaccines. As well, the immunostimulatory action of E. coli DNA may be used to augment the humoral response induced by a DNA vaccine.     

Priming of immune responses to hepatitis B surface antigen in young mice immunized in the presence of maternally derived antibodies

Early vaccination is necessary to protect infants from various infectious diseases. However, this is often unsuccessful largely due to the immaturity of the neonatal immune system. Furthermore, maternally derived antibodies can interfere with active immunization. We have previously shown in young mice that immune responses against several different antigens can be improved by the addition of oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG ODN). In this study we have evaluated immunization of newborn (1-7-day-old) BALB/c mice against hepatitis B surface antigen (HBsAg), with alum and/or CpG ODN, in the presence of high levels of maternal antibody against HBsAg (anti-HBs). Seroconversion rates and anti-HBs titers were compared to those induced by a HBsAg-expressing plasmid, since other studies had suggested DNA vaccines to be superior to protein vaccines in young mice with maternal antibody. HBsAg/alum/CpG ODN was superior to DNA vaccine in inducing HBsAg-specific CTL responses in young mice in the presence of maternally transferred anti-HBs antibodies. However, B cell responses to both HBsAg/alum/CpG ODN and DNA vaccines remained weak in the presence of maternally transferred anti-HBs antibodies.     

Antibody responses to Brugia malayi antigens induced by DNA vaccination

BACKGROUND: DNA vaccination is a convenient means of immunizing animals with recombinant parasite antigens. DNA delivery methods are believed to affect the qualitative nature of immune responses to DNA vaccines in ways that may affect their protective activity. However, relatively few studies have directly compared immune responses to plasmids encoding the same antigens after injection by different routes. Therefore, the purpose of this study was to explore the influence of the route of administration on antibody responses to plasmids encoding antigens from the filarial nematode parasite Brugia malayi. METHODS: Four B. malayi genes and partial genes encoding paramyosin (BM5), heat shock protein (BMHSP-70), intermediate filament (BMIF) and a serodiagnostic antigen (BM14) were inserted in eukaryotic expression vectors (pJW4303 and pCR trade mark 3.1). BALB/c mice were immunized with individual recombinant plasmids or with a cocktail of all four plasmids by intramuscular injection (IM) or by gene gun-intradermal inoculation (GG). Antibody responses to recombinant antigens were measured by ELISA. Mean IgG1 to IgG2a antibody ratios were used as an indicator of Th1 or Th2 bias in immune responses induced with particular antigens by IM or GG immunization. The statistical significance of group differences in antibody responses was assessed by the non-parametric Kruskal-Wallis test. RESULTS: Mice produced antibody responses to all four filarial antigens after DNA vaccination by either the IM or GG route. Antibody responses to BM5 paramyosin were strongly biased toward IgG1 with lower levels of IgG2a after GG vaccination, while IM vaccination produced dominant IgG2a antibody responses. Antibody responses were biased toward IgG1 after both IM and GG immunization with BMIF, but antibodies were biased toward IgG2a after IM and GG vaccination with BMHSP-70 and BM14. Animals injected with a mixture of four recombinant plasmid DNAs produced antibodies to all four antigens. CONCLUSIONS: Our results show that monovalent and polyvalent DNA vaccination successfully induced antibody responses to a variety of filarial antigens. However, antibody responses to different antigens varied in magnitude and with respect to isotype bias. The isotype bias of antibody responses following DNA vaccination can be affected by route of administration and by intrinsic characteristics of individual antigens.     

Immunization with recombinant adenovirus synthesizing the secretory form of Japanese encephalitis virus envelope protein protects adenovirus-exposed mice against lethal encephalitis

Replication-defective recombinant adenoviruses (RAds) were constructed that synthesized the pre-membrane and envelope (E) proteins of Japanese encephalitis virus (JEV). Recombinant virus RAdEa synthesized Ea, the membrane-anchored E protein, and RAdEs synthesized Es, the secretory E protein. Compared with RAdEs, RAdEa replicated poorly in HEK 293A cells and synthesized lower amounts of E protein. Oral immunization of mice with RAds generated low titers of anti-JEV antibodies that had little JEV neutralizing activity. Intra-muscular (IM) immunization of mice with either RAd generated high titers of anti-JEV antibodies. Interestingly, RAdEa induced only low titers of JEV neutralizing antibodies. Titers were significantly higher in case of RAdEs immunization. Splenocytes from mice immunized IM with RAds secreted large amounts of interferon-γ and moderate amounts of interleukin-5 in the presence of JEV and showed cytotoxic activity against JEV-infected cells. Naïve mice immunized IM with RAdEs showed complete protection against a lethal dose of JEV given intra-cerebrally. In order to study the effect of the pre-existing adenovirus 5 (Ad5) immunity on the outcome of the RAdEs immunization, mice were exposed to Ad5 through IM or intra-nasal (IN) routes before immunization with RAdEs. Mice exposed to Ad5 through the IN route, when immunized with RAdEs given IM, or those exposed to Ad5 through the IM route, when immunized with RAdEs given IN, were completely protected against lethal JEV challenge.     

EV71灭活疫苗（人二倍体细胞）在恒河猴婴猴模型中的免疫保护性分析

肠道病毒71型作为引起儿童群体常见传染性手足口病（HFMD）的主要病原,具有导致少量感染个体出现脑炎等神经系统病变以及相关心肺功能衰竭的病理学特性．因此其预防性疫苗的研发具有重要的公共卫生意义．在前期工作的基础上,一种EV71灭活病毒疫苗（人二倍体细胞）在本研究中基于恒河猴婴猴模型进行了相应的免疫保护性分析．以160EU剂量对2～3月龄婴猴进行0,4周免疫后,动物在第4周接受了剂量为10。～CCID50的病毒经呼吸道的攻击．对病毒攻击后动物在14天内的临床症状、血液生物学、器官病原学分布以及病理学检测的动态观察表明,经疫苗免疫的动物未出现对照动物所具有的特征性临床表现,其血液生物学及病理学检测均无异常．同时,器官病原学分布亦呈阴性．结合动物中和抗体的明确增长及对照动物的综合表现分析,本文的工作证实了该EV71灭活病毒疫苗（人二倍体细胞）在恒河猴婴猴体内的免疫保护性．     

Mucosal Immunization of Cynomolgus Macaques with the VSVΔG/ZEBOVGP Vaccine Stimulates Strong Ebola GP-Specific Immune Responses

Background

Zaire ebolavirus (ZEBOV) produces a lethal viral hemorrhagic fever in humans and non-human primates.

Methodology/Principal Findings

We demonstrate that the VSVΔG/ZEBOVGP vaccine given 28 days pre-challenge either intranasally (IN), orally (OR), or intramuscularly (IM) protects non-human primates against a lethal systemic challenge of ZEBOV, and induces cellular and humoral immune responses. We demonstrated that ZEBOVGP-specific T-cell and humoral responses induced in the IN and OR groups, following an immunization and challenge, produced the most IFN-γ and IL-2 secreting cells, and long term memory responses.

Conclusions/Significance

We have shown conclusively that mucosal immunization can protect from systemic ZEBOV challenge and that mucosal delivery, particularly IN immunization, seems to be more potent than IM injection in the immune parameters we have tested. Mucosal immunization would be a huge benefit in any emergency mass vaccination campaign during a natural outbreak, or following intentional release, or for mucosal immunization of great apes in the wild.     

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.     

Evaluation of rabies virus neutralizing antibody titres induced by intramuscular inoculation of rabies DNA vaccine in mice and Bonnet monkeys (Macaca radiata)

A rabies DNA vaccine consisting of plasmid DNA expressing the rabies virus surface glycoprotein was injected (im) twice at two week interval to outbred swiss mice or Bonnet monkeys (Macaca radiata) and the levels of rabies virus neutralizing antibody (VNA) titres were examined over a one year period. In mice, the VNA titre was maintained above the minimum protective level (0.5 I.U./ml) up to 10 months after primary immunization, while in monkeys, the titre dropped below the protective level by 6 months. An anamnestic B cell response was seen in both mice and monkeys following the administration of a booster dose, 10 and 6 months after the primary immunization, respectively. These results indicate that im injection of rabies DNA vaccine induces VNA in nonhuman primates and mice unlike intradermal (id) immunization, which was shown to induce VNA only in mice but not in monkeys. This is the first report on the induction of VNA in nonhuman primates by im inoculation of rabies DNA vaccine.     

应用改良流式法检测猕猴和食蟹猴体内血型抗体水平的分布情况

绝大部分灵长类动物存在与人类相似的ABO血型系统,该研究采用改良流式法(flow cytometry method,FCM)检测猕猴及食蟹猴血清中血型抗体水平的分布情况。以流式细胞术为基础,使用商品化人源红细胞为靶细胞,并通过加入特异性荧光标记的抗人IgM或IgG二抗,对收集的实验用猕猴及食蟹猴的血清样本进行检测,以人类健康受试者的血清样本为对照,比较两者血型抗体水平的差异。结果显示:预先用人O型浓缩红细胞吸附猴血清中所含种属间非特异性抗体后,FCM法能够准确检测其血型抗体水平及分型,并且发现猴血清中天然血型抗体的水平明显低于健康人(P<0.05)。由此得出:通过预处理清除非特异性抗体的干扰后,FCM法同样适用于灵长类动物血清中血型抗体的检测,也为构建灵长类动物模拟人ABO血型不合器官移植模型提供了技术保障和实验数据。     

Skin Vaccination against Rotavirus Using Microneedles: Proof of Concept in Gnotobiotic Piglets

Live-attenuated oral rotavirus (RV) vaccines have lower efficacy in low income countries, and additionally are associated with a rare but severe adverse event, intussusception. We have been pursuing the development of an inactivated rotavirus vaccine (IRV) using the human rotavirus strain CDC-9 (G1P[8]) through parenteral immunization and previously demonstrated dose sparing and enhanced immunogenicity of intradermal (ID) unadjuvanted IRV using a coated microneedle patch in comparison with intramuscular (IM) administration in mice. The aim of this study was to evaluate the immune response and protection against RV infection and diarrhea conferred by the administration of the ID unadjuvanted IRV using the microneedle device MicronJet600^® in neonatal gnotobiotic (Gn) piglets challenged with virulent Wa G1P[8] human RV. Three doses of 5 μg IRV when administered intradermally and 5 μg IRV formulated with aluminum hydroxide [Al(OH)₃] when administered intramuscularly induced comparable rotavirus-specific antibody titers of IgA, IgG, IgG avidity index and neutralizing activity in sera of neonatal piglets. Both IRV vaccination regimens protected against RV antigen shedding in stools, and reduced the cumulative diarrhea scores in the piglets. This study demonstrated that the ID and IM administrations of IRV are immunogenic and protective against RV-induced diarrhea in neonatal piglets. Our findings highlight the potential value of an adjuvant sparing effect of the IRV ID delivery route.     

An attempt to predict anergy in tuberculosis suspect cynomolgus monkeys.

Acid-fast microorganisms were identified from the tuberculous lesions of a male cynomolgus monkey (Macaca fascicularis). Twenty-two other cynomolgus monkeys housed in the same room were presumed exposed to tuberculosis (Mycobacterium spp.). In addition to standard intradermal (ID) tuberculin testing, clinicians attempted to evaluate the immune status of these monkeys in order to identify animals exhibiting false negative (anergy) ID tuberculin tests. Twenty-one of the potentially exposed monkeys were immunized with tetanus toxoid (TT). Tetanus antitoxin (TAT) titers were measured before and after immunization. The delayed cutaneous hypersensitivity (DCH) reaction to TT was evaluated using a commercially available human test panel. Some animals did not exhibit a DCH reaction to TT. At necropsy 1 of the 21 animals exhibited tuberculous lesions, and acid-fast microorganisms were identified on direct smears of lymphatic tissue of a second animal. Although reported to be of value in assessing the cellular immune status of rhesus monkeys (Macaca mulatta), the delayed cutaneous hypersensitivity response to tetanus toxoid was not helpful during this outbreak in identifying cynomolgus monkeys infected with M. tuberculosis, or in interpreting suspect ID tuberculin tests.     

Protection of mice from rabies by intranasal immunization with inactivated rabies virus.

The mucosal immunization method is a needle-free alternative way of vaccination. This study evaluated the efficacy of mucosal immunization for rabies. Mice were intranasally administered five times with inactivated and concentrated rabies virus antigen (CRV) supplemented with or without cholera toxin (CT). The anti-rabies virus antibody titer of mice intranasally immunized with CRV plus CT (CRV/CT) was comparable to that of mice intraperitoneally immunized twice with the same amount of CRV. Virus neutralizing (VNA) titers of mice immunized intranasally with CRV/CT were slightly lower than those of intraperitoneally immunized mice. Both anti-rabies virus ELISA antibody and VNA titers of mice immunized with CRV without CT were significantly lower than those of mice immunized with CRV/CT. In mice intranasally immunized with CRV/CT, and intraperitoneally immunized mice, high levels of IgG(2a) antibody were detected, suggesting the activation of Th1-driven cellular immunity by the two ways of immunization. All immunized mice were challenged intracerebrally with a lethal dose of virulent rabies virus CVS strain. The survival rates of mice immunized with CRV/CT and CRV without CT were 67% and 17%, respectively, while the rate of intraperitoneally immunized mice was 100%. Antigen-specific whole IgG and IgG(2a), and VNA titers of survived mice were significantly higher than those of dead mice at the challenge day. These data suggest the possibility of intranasal immunization with inactivated antigen as a rabies vaccination strategy and the importance of a mucosal adjuvant such as CT.     

Titration of tetanus antitoxin by passive hemagglutination. II. Serological characteristics of antitoxin production in rabbits and monkeys.

1) Production of tetanus antitoxin in rabbits and monkeys was followed by passive hemagglutination (HA) and toxin-neutralization (TN) tests. The HA activity was observed in both IgM and IgG in both animal species. 2) In rabbits, IgM antitoxin was detected as early as in 7 days, reached the maximum titer in 10--14 days, and disappeared in 3 weeks after the primary immunization. Antitoxin of IgG class was detected in 10 days, and increased gradually. The ratio of HA/TN titers ("serum ratio") was high at an early stage of primary immunization and approached the unity in 3--4 weeks. Unlike the case of guinea pigs, IgM was found to contribute greatly to this high level of ratio. Besides, most rabbits produced IgG antitoxin of high ratios at early stages of immunization. 3) The immune response of monkeys showed a pattern very similar to that of rabbits except a few days' delay in the time course of antitoxin titers. No IgG antitoxin with a high serum ratio was demonstrated. Therefore, the high serum ratio of early sera could be accounted for mainly by IgM. 4) In response to the secondary immunization, no IgM antitoxin was detected in either animal species. 5) No definite correlation between serum ratio and avidity in terms of "dilution ratio" was demonstrated. However, both the dilution ratio and serum ratio were high at an early stage of immunization and gradually decreased, though the magnitudes of the ratios were variable depending on individual animals.     

Nasal Immunization of Mice with Human Papillomavirus Type 16 Virus-Like Particles Elicits Neutralizing Antibodies in Mucosal Secretions

To specifically induce a mucosal antibody response to purified human papillomavirus type 16 (HPV16) virus-like particles (VLP), we immunized female BALB/c mice orally, intranasally, and/or parenterally and evaluated cholera toxin (CT) as a mucosal adjuvant. Anti-HPV16 VLP immunoglobulin G (IgG) and IgA titers in serum, saliva, and genital secretions were measured by enzyme-linked immunosorbent assay (ELISA). Systemic immunizations alone induced HPV16 VLP-specific IgG in serum and, to a lesser extent, in genital secretions but no secretory IgA. Oral immunization, even in the presence of CT, was inefficient. However, three nasal immunizations with 5 μg of VLP given at weekly intervals to anesthetized mice induced high (>10⁴) and long-lasting (>15 weeks) titers of anti-HPV16 VLP antibodies in all samples, including IgA and IgG in saliva and genital secretions. CT enhanced the VLP-specific antibody response 10-fold in serum and to a lesser extent in saliva and genital secretions. Nasal immunization of conscious mice compared to anesthetized mice was inefficient and correlated with the absence of uptake of a marker into the lung. However, a 1-μg VLP systemic priming followed by two 5-μg VLP intranasal boosts in conscious mice induced both HPV16 VLP-specific IgG and IgA in secretions, although the titers were lower than in anesthetized mice given three intranasal immunizations. Antibodies in serum, saliva, and genital secretions of immunized mice were strongly neutralizing in vitro (50% neutralization with ELISA titers of 65 to 125). The mucosal and systemic/mucosal HPV16 VLP immunization protocols that induced significant titers of neutralizing IgG and secretory IgA in mucosal secretions in mice may be relevant to genital HPV VLP-based human vaccine trials.     

Plasmodium vivax thrombospondin related adhesion protein: immunogenicity and protective efficacy in rodents and Aotus monkeys

The thrombospondin related adhesion protein (TRAP) is a malaria pre-erythrocytic antigen currently pursued as malaria vaccine candidate to Plasmodium falciparum. In this study, a long synthetic peptide (LSP) representing a P. vivax TRAP fragment involved in hepatocyte invasion was formulated in both Freund and Montanide ISA 720 adjutants and administered by IM and subcutaneous routes to BALB/c mice and Aotus monkeys. We measured specific humoral immune responses in both animal species and performed a sporozoite challenge in Aotus monkeys to assess the protective efficacy of the vaccine. After immunization both mice and Aotus seroconverted as shown by ELISA, and the specific anti-peptide antibodies cross reacted with the parasite in IFAT assays. Only two out of six immunized animals became infected after P. vivax sporozoite challenge as compared with four out of six animals from the control group. These results suggest that this TRAP fragment has protective potential against P. vivax malaria and deserves further studies as vaccine candidate.     

Comparative immunogenicity analysis of intradermal versus intramuscular administration of SARS-CoV-2 RBD epitope peptide-based immunogen In vivo

COVID-19 pandemic has caused severe disruption of global health and devastated the socio-economic conditions all over the world. The disease is caused by SARS-CoV-2 virus that belongs to the family of Coronaviruses which are known to cause a wide spectrum of diseases both in humans and animals. One of the characteristic features of the SARS-CoV-2 virus is the high reproductive rate (R₀) that results in high transmissibility of the virus among humans. Vaccines are the best option to prevent and control this disease. Though, the traditional intramuscular (IM) route of vaccine administration is one of the effective methods for induction of antibody response, a needle-free self-administrative intradermal (ID) immunization will be easier for SARS-CoV-2 infection containment, as vaccine administration method will limit human contacts. Here, we have assessed the humoral and cellular responses of a RBD-based peptide immunogen when administered intradermally in BALB/c mice and side-by-side compared with the intramuscular immunization route. The results demonstrate that ID vaccination is well tolerated and triggered a significant magnitude of humoral antibody responses as similar to IM vaccination. Additionally, the ID immunization resulted in higher production of IFN-γ and IL-2 suggesting superior cellular response as compared to IM route. Overall, our data indicates immunization through ID route provides a promising alternative approach for the development of self-administrative SARS-CoV-2 vaccine candidates.     

不同来源血浆对静注人免疫球蛋白中抗-HBs、白喉抗体效价的影响

调查分析不同来源原料血浆对静注免疫球蛋白(IVIG)制品内的抗-HBs、白喉抗体效价的影响。选择6个单采血浆站,对其提供的血浆为原料制备的IVIG所含的抗-HBs抗体、白喉抗体效价进行了测定。检测结果显示,用A、B、C、D、E、F编号的6个相应血浆站采集的血浆为原料制备成IVIG其抗-HBs抗体(IU/g)效价分别为33.77、103.95、70.94、132.45、78.84、58.28;白喉抗体平均效价分别为5.17、7.36、4.26、7.67、10.14、9.24。6个单采血浆站间的IVIG制品中白喉抗体效价无明显差异,但抗-HBs效价却存有显著差异。     

基因枪法和肌内注射法免疫HCV NS3/4A诱导小鼠免疫应答的比较

目的比较肌内注射法和基因枪法对免疫效果的影响。方法将携带HCV NS3/4A基因的质粒pcDNA3.1-NS3/4A,分别肌内注射和基因枪免疫BALB/c小鼠。基因枪免疫采用2μg/只和10μg/只两种剂量,肌内注射免疫的剂量为100μg/只,共免疫3次。分别于第3次免疫后10 d和20 d,收集小鼠血清、分离脾细胞;ELISA法检测小鼠血清中特异性抗体水平;ELIspot检测小鼠IFN-γI、L-2和IL-4;非放射性细胞毒性试验检测其对肿瘤细胞的杀伤作用,从而比较肌内注射和基因枪法激发小鼠产生体液免疫和细胞免疫应答的影响。结果免疫后第10 d检测结果表明,2μg/只和10μg/只基因枪法免疫产生的抗体效价分别为1∶500和1∶1 000,100μg/只肌内注射免疫产生的抗体效价为1∶1 000。第20 d再次检测,基因枪法产生的抗体效价仍为1∶500和1∶1 000,肌内注射降低为1∶500。2μg/只和10μg/只基因枪免疫产生的IFN-γ和IL-2均高于100μg/只肌内注射免疫。但这两种免疫方法均未激发IL-4的水平。在不同的效靶比情况下,10μg/只和2μg/只基因枪免疫激发的CTL细胞杀伤活性均高于100μg/只肌内注射免疫。结论基因枪法免疫小鼠诱导的体液免疫和细胞免疫应答均显著高于肌内注射免疫。     

Production of IgG antibodies and enhanced response of nude mice to DNP-AE-dextran.

DNP-AE-dextran, prepared by the binding of DNP-epsilon-aminocaproyl residues to animoethylated dextran (predominantly alpha-1,6-linked), induced a T-independent anti-DNP antibody response in mice. However, certain differences were observed between the response to this antigen in normal andnude mice. Thus, the antibody titers of nu/nu mice from day 10 to 38 after immunization were significantly higher than those of nu/+ controls. Furthermore, DNP-AE-dextran induced a weak secondary response in nu/+ but not in nu/nu mice. For both thymusless and normal mice the production of IgG in addition to IgM antibodies to DNP-AE-dextran could be established. The former included antibodies of the IgG1 subclass which were considered to be particularly thymus dependent (1). The higher response of nu/nu mice was reflected mainly in the increased production of IgG antibodies. Under the influence of a graft-vs-host reaction, a 10-fold increase in antibody titers to DNP-AE-dextran was observed, due entirely to an enhanced IgG response.     

非人灵长类动物种质冷冻保存研究进展和展望

非人灵长类动物是生物多样性的重要组成部分,也是生物医学研究的珍贵实验动物,然而,由于人类活动、栖息地破坏、狩猎和遗传隔离等原因,许多非人灵长类动物的野生种群数量急剧下降,甚至处于灭绝的边缘。种质冷冻保存对拯救非人灵长类动物和保存遗传物质资源具有重要意义。本文综述了新大陆猴、旧大陆猴和巨猿等类群动物精子、卵子、胚胎和性腺组织等种质冷冻保存的研究进展,介绍了狨猴、松鼠猴、恒河猴、食蟹猴和黑猩猩等种质冷冻保存的主要方法,并对未来种质冷冻保存的研究方向进行了讨论。