Evaluation of recombinant A/Victoria/3/75 (H3N2) influenza neuraminidase mutants as potential broad-spectrum subunit vaccines against influenza A

Current influenza vaccines require repeated administration for long-term protection. Failure to develop broad-spectrum vaccines may be attributed to the chronic presentation of hypervariable, immunodominant epitopes displayed on the viral surface that keep the immune response somewhat fixed and limited by suppression of broadly neutralizing, low-titered antibodies. To test this hypothesis, we have attempted to dampen the immunogenicity of variable epitopes and potential immunodominant domains of the A/Victoria/3/75 (H3N2) neuraminidase by site-directed mutagenesis. The results suggest that the neuraminidase structure is extremely flexible, since many substitution combinations were tolerated, and constitute proof-of-principle that the antigenicity of this protein can be modulated to a large extent. However, mice immunized with neuraminidase mutants containing multiple amino acid substitutions showed a reduced protection rate against heterologous virus in comparison with the reference groups.     

Ability of temperature-sensitive mutants of the recombinant influenza S/N (H2N1) virus to induce immunity to parental (H0N1 and H2N2) viruses

The behavior in mice of two thermosensitive (ts) mutants (denoted ts217 and ts700) of the recombinant influenza virus S/N (H2N1) was studied. The parental thermoresistant (tr) virus and both of the mutants were capable of inducing protection against pneumotropic A/Singapore (H2N2) and A/WS (H0N1) challenge viruses. Immunity against the Singapore virus, with which the S/N virus shared the hemagglutinin, developed earlier than against the WS virus, with which the S/N virus shared the neuraminidase. The tr and ts217 viruses were immunologically more active than the ts700 virus. The first two viruses grew markedly better in mouse lungs than did the latter. In the course of ts217 virus replication in vivo, revertants capable of growing at 39 degrees C appeared readily. On the other hand, the ts700 virus proved to be genetically stable. These data seem to provide evidence of a linkage between the stability of the ts phenotype, reproductive capacity in mouse lungs, and immunogenicity in the viruses examined.     

Standard Molar Enthalpy of Formation of RE（ C5H8NS2 ）3 （C12H8N2）

Four solid ternary complexes of RE (C5H8NS2)3(C12H8N2) (RE=Eu, Gd, Tb, Dy) were synthesized in absolute ethanol by rare earth chloride low hydrate with the mixed ligands of ammonium pyrrolidinedi-thiocarbamate (APDC) and 1, 10-phenanthroline*H2O (o-phen*H2O) in the ordinary laboratory atmosphere without any cautions against moisture or air sensitivity. IR spectra of the complexes show that the RE3 coordinated with six sulfur atoms of three PDC- and two nitrogen atoms of o-phen*H2O. It was assumed that the coordination number of RE3 is eight. The constant-volume combustion energies of the complexes, ΔcU, were determined as (-16937.88±9.79 ), (-17588.79±8.62 ), (-17747.14±8.25 ) and (-17840.37±8.87 ) kJ*mol-1, by a precise rotating-bomb calorimeter at 298.15 K. Its standard molar enthalpies of combustion, ΔcHθm, and standard molar enthalpies of formation, ΔfHθm, were calculated as (-16953.37±9.79), (-17604.28±8.62), (-17762.63±8.25), (-17855.86±8.87) kJ*mol-1 and (-857.04±10.52), (-282.43±9.58), (-130.08±9.13), (-55.75±9.83) kJ*mol-1.     

Effectiveness of inactivated influenza vaccine among nursing home residents during an influenza type A (H3N2) epidemic

We performed serological phenotyping of HLA antigens in 175 patients with rheumatoid arthritis (RA) with (n = 41) and without (n = 134) renal involvement (RI), and DNA typing of HLA class II alleles in 75 patients. Among the patients with RA, the frequency of serologically determined HLA-DR4 was found to be significantly increased (odds ratio: 1.8, confidence interval: 1.3-2.5, p = 2.4x10(-4)). In the patients without RI, the frequency of serological DR4 significantly increased (odds ratio: 2.2, confidence interval: 1.6-3.3, p = 2. 6x10(-5)). On the other hand, among the patients with RI, a serological determinant, DR15, did significantly increase (odds ratio: 2.7, confidence interval: 0.9-8.4, p = 1.2x10(-3)) in comparison to the controls. At the DNA level, we found that the association of Japanese RA patients with serological HLA-DR4 was based on that with a genotype of HLA-DRB1*0405 (odds ratio: 2.4, confidence interval: 1.5-4.0, p = 4.4x10(-4)) and also found an association of HLA-DRB1*1501 (odds ratio: 2.8, confidence interval: 1.2-6.6, p = 0.017) with RA patients having RI. Our results confirmed the association of HLA-DRB1*04 with RA over the ethnic barrier at the DNA level. Our results also suggested a distinct genetic effect of HLA-DRB1*1501 in the aspect of the susceptibility of RI in RA.     

Comparisons of highly virulent H5N1 influenza A viruses isolated from humans and chickens from Hong Kong

Genes of an influenza A (H5N1) virus from a human in Hong Kong isolated in May 1997 were sequenced and found to be all avian-like (K. Subbarao et al., Science 279:393-395, 1998). Gene sequences of this human isolate were compared to those of a highly pathogenic chicken H5N1 influenza virus isolated from Hong Kong in April 1997. Sequence comparisons of all eight RNA segments from the two viruses show greater than 99% sequence identity between them. However, neither isolate's gene sequence was closely (>95% sequence identity) related to any other gene sequences found in the GenBank database. Phylogenetic analysis demonstrated that the nucleotide sequences of at least four of the eight RNA segments clustered with Eurasian origin avian influenza viruses. The hemagglutinin gene phylogenetic analysis also included the sequences from an additional three human and two chicken H5N1 virus isolates from Hong Kong, and the isolates separated into two closely related groups. However, no single amino acid change separated the chicken origin and human origin isolates, but they all contained multiple basic amino acids at the hemagglutinin cleavage site, which is associated with a highly pathogenic phenotype in poultry. In experimental intravenous inoculation studies with chickens, all seven viruses were highly pathogenic, killing most birds within 24 h. All infected chickens had virtually identical pathologic lesions, including moderate to severe diffuse edema and interstitial pneumonitis. Viral nucleoprotein was most frequently demonstrated in vascular endothelium, macrophages, heterophils, and cardiac myocytes. Asphyxiation from pulmonary edema and generalized cardiovascular collapse were the most likely pathogenic mechanisms responsible for illness and death. In summary, a small number of changes in hemagglutinin gene sequences defined two closely related subgroups, with both subgroups having human and chicken members, among the seven viruses examined from Hong Kong, and all seven viruses were highly pathogenic in chickens and caused similar lesions in experimental inoculations.     

Susceptibilities to rimantadine of influenza A/H1N1 and A/H3N2 viruses isolated during the epidemics of 1988 to 1989 and 1989 to 1990

Clinical isolates of influenza A viruses identified during outbreaks in two winters were tested for their rimantadine susceptibilities by an enzyme-linked immunosorbent assay modified from that described previously by Belshe et al. (R. B. Belshe, B. Burk, F. Newman, R. L. Cerruti, and I. S. Sim, J. Virol. 62:1508-1512, 1988). The infectivity titer and the 50% inhibitory concentration of rimantadine were calculated for each virus. Of 105 influenza virus A isolates tested, 28 influenza A/H1N1 isolates from the 1988 and 1989 outbreak and 77 influenza A/H3N2 isolates from the outbreak in following year, were susceptible to the antiviral action of rimantadine.     

The haemagglutinins of influenza A (H1N1) viruses in the 'O' or 'D' phases exhibit biological and antigenic differences

Influenza A (H1N1) viruses when initially isolated in mammalian cell cultures (MDCK cells) had different agglutination reactions with chicken and guinea-pig erythrocytes compared to the same viruses after passage. On first isolation the virus HA resembled the 'O' phase viruses described originally by Burnet and Bull and agglutinated mammalian but not avian erythrocytes. After passage, the virus HA resembled a classical 'D' phase virus and agglutinated both avian and mammalian erythrocytes. Monoclonal and polyclonal antisera detected antigenic differences between the HAs of the viruses in the 'O' and 'D' phases. The 'O' phase virus HA reacted preferentially with antibodies in post infection human antisera. Viruses in the 'O' phase replicated poorly in the allantoic cavity of embryonated hens' eggs whilst 'D' phase virus replicated in both MDCK cells and in embryonated hens' eggs. At least three distinguishable subpopulations of influenza A (H1N1) viruses may co-exist in clinical throat swab material, including viruses possessing HAs in the 'O' and 'D' phases and other 'D' phase viruses cultivable in embryonated hens' eggs but antigenically distinguishable from the corresponding 'D' phase virus in MDCK cells.     

三元配合物Pr[(C5H8NS2)3(C12H8N2)]生成反应的热动力学

在无水乙醇中 ,用吡咯烷二硫代氨基甲酸铵 (APDTC)和 1,10 邻菲咯啉 (o phen·H2 O)与PrCl3·3 .75H2 O作用 ,合成了三元固态配合物 ,确定它的组成为Pr[(C5H8NS2 ) 3(C1 2 H8N2 ) ]。X粉末衍射说明它为一新相化合物。IR光谱说明配合物中Pr3 分别与 3个APDTC的 6个硫原子双齿配位 ,同时与o phen的 2个氮原子双齿配位 ,配位数为 8。TG DTG分析显示其热分解为一步生成Pr2 S3 2C。用微量热计测定了 2 98.15K下水合氯化镨及两个配体在无水乙醇中的溶解焓 ,两个配体醇溶液的混合焓及不同温度下标题化合物液相生成反应的焓变。在实验和计算基础上 ,得到了液相生成反应的热力学参数 (活化焓、活化熵和活化自由能 ) ,速率常数和动力学参数 (表现活化能、频率因子和反应级数 ) ,通过合理的热化学循环 ,求得了 2 98 15K时标题化合物的固相反应焓变。     

Phylogenetic analysis of the core histones H2A, H2B, H3, and H4

The class I cytokine receptors consist of multiple subunits without any intrinsic enzymatic activities. Receptors for a subset of cytokines with overlapping biological activities often share a common receptor subunit with a signaling function. Each receptor regulates its specific signaling pathways, as well as common pathways depending on the target cell type.     

Cross-protection of mice immunized with different influenza A (H2) strains and challenged with viruses of the same HA subtype

Cross-protection of mice immunized with inactivated preparations of human and avian influenza A (H2) viruses was determined after lethal infection with mouse-adapted (MA) variants of human A/Jap x Bell/57 (H2N1) and avian A/NJers/78 (H2N3) viruses. The MA variants differed from the original strains by acquired virulence for mice and changes in the HA antigenicity. These studies indicated that mice vaccinated with human influenza A (H2) viruses were satisfactorily protected against challenge with A/Jap x Bell/57-MA variant; the survival rate was in the range of 61%-88.9%. Immunization of mice with the same viral preparations provided lower levels of protection against challenge with A/NJers/78-MA variant. Vaccination of mice with the avian influenza A (H2) viruses induced better protection than with human strains against challenge with both MA variants. Challenge with A/NJers/78-MA variant revealed that 76.2%-95.2% of animals were protected when vaccinated with avian influenza virus strains isolated before 1980, and that the protection reached only 52.4%-60.0% in animals vaccinated with strains isolated in 1980-1985. The present study revealed that cross-protection experiments in a mouse model could provide necessary information for the development of appropriate influenza A (H2) virus vaccines with a potential for these viruses to reappear in a human population.     

Thyrotropin-releasing activity of histone H2A, H2B and peptide MB35

Histones possess multiple hormone-like activities. We studied the specificity and signal transduction pathways involved in the thyrotrophin (TSH)-releasing activity of histones H2A, H2B and peptide MB35, a H2A fragment, using perifused and incubated dispersed rat pituitary cells and measuring TSH release by a specific R1A. Histones released TSH in a dose- and time-dependent fashion while peptide MB35 behaved as a weaker secretagogue. Trifluoperazine and EGTA blocked histone-stimulated TSH release while forskolin and other cAMP enhancers did not. We conclude that the TSH-releasing activity of histones H2A and H2B is mediated by calcium- and diacylglycerol-associated pathways.     

Protection by the heavy metal chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) against the lethal action of botulinum neurotoxin A and B

The ability of N,N,N',N'-tetrakis (2-pyridylmethyl)-ethyenediamine (TPEN) to protect against botulinum neurotoxin (BoNT) A and B was examined in vivo in mice. To determine the protective efficacy of TPEN, mice were injected i.p. with TPEN as a single bolus or as multiple injections 30 min before and 0, 2, 4 and 6 hr following i.v. challenges with BoNT-A or -B. TPEN treatment did not alter the 24 hr lethality of BoNT but did produce a significant delay in the time to death. For a moderate dose of serotype A (20 LD50), five divided doses of TPEN prolonged the time to death from 7.8 +/- 0.4 hr to 9.9 +/- 0.5 hr. For serotype B, examined under comparable conditions, the prolongation of the time to death was from 6.1 +/- 0.2 hr to 9.4 +/- 0.6 hr. The range of TPEN doses that could be examined in vivo was limited by its acute toxicity. Although low doses of TPEN (< or = 10 mg/kg) were well tolerated, higher doses (> or = 30 mg/kg) led to ataxia, loss of coordination, convulsions and death in 20.3 min or less. In clonal NG108-15 cells, TPEN was found to produce cytotoxicity as revealed by increases in the secretion of the marker enzyme lactate dehydrogenase (LDH), and enhanced reactivity with the vital dye trypan blue. From LDH concentration-response data determined 24 hr after addition of TPEN, the threshold concentration for observing cytotoxicity was 10 microM and the IC50 was 19.8 microM. At the highest TPEN concentration tested (100 microM), cytotoxicity was detected 8 hr after TPEN addition and increased in severity over a 3 day period. The cytotoxicity in NG108-15 cells appears to be distinct from the rapid-onset toxicity observed in whole animals. These results suggest that TPEN may be of potential benefit in delaying the lethal actions of BoNT-A and -B, but its use is limited by its initial and delayed toxicity. Since the therapeutic and toxic actions of TPEN are both related to zinc chelation, the use of TPEN would need to be restricted to low doses as part of a combination therapy.     

Er(ONO)(C8H7O3)2(H2O)3配合物的合成、表征及热分解动力学机理研究

合成了亚硝酸根·二(4-羟基-3-甲氧基-苯甲醛)·三水合铒(Ⅲ)配合物Er(ONO)(C8H7O3)2(H2O)3,用元素分析、红外光谱、摩尔电导、热重分析等手段进行表征.配合物的中心金属离子Er(Ⅲ)与2个香兰素配体中的2个酚羟基氧和2个甲氧基氧、亚硝酸根中的1个氧及3个配位水分子中的3个氧原子发生配位,配位数为8.用热重法研究了配合物的热分解动力学机理.     

Antitumour activity and schedule dependency of 8-chloroadenosine-3'',5''-monophosphate (8-ClcAMP) against human tumour xenografts

We have mapped the chromosomal locations of three human nuclear genes for putative components of the apparatus of mitochondrial gene expression, using a combination of in situ hybridization and interspecies hybrid mapping. The genes RPMS12 (mitoribosomal protein S12, a conserved protein component of the mitoribosomal accuracy center), TUFM (mitochondrial elongation factor EF-Tu), and AFG3L1 (similar to the yeast genes Afg3 and Rca1 involved in the turnover of mistranslated or misfolded mtDNA-encoded polypeptides) were initially characterized by a combination of database sequence analysis, PCR, cloning, and DNA sequencing. RPMS12 maps to chromosome 19q13.1, close to the previously mapped gene for autosomal dominant hearing loss DFNA4. The TUFM gene is located on chromosome 16p11.2, with a putative pseudogene or variant (TUFML) located very close to the centromere of chromosome 17. AFG3L1 is located on chromosome 16q24, very close to the telomere. By virtue of their inferred functions in mitochondria, these genes should be regarded as candidates of disorders sharing features with mitochondrial disease syndromes, such as sensorineural deafness, diabetes, and retinopathy.     

The outbreak of equine influenza (H3N8) in the United Kingdom in 1989: diagnostic use of an antigen capture ELISA

In July 1989 influenza A/equine-2 (H3N8) was isolated from a nasopharyngeal swab taken from a non-thoroughbred horse exhibiting acute clinical respiratory disease. This was the first isolation of equine influenza virus in the United Kingdom since 1981. Subsequent investigations of acute respiratory disease in horses indicated that the infection was dispersed throughout the UK. However, unlike the previous epidemic of 1979, the first horses from which the virus was isolated had been vaccinated. This outbreak of influenza provided an opportunity to evaluate an antigen capture ELISA, directed against the influenza virus nucleoprotein, as a rapid method for detecting virus in the nasopharyngeal secretions of naturally infected horses.     

Genomic study of hemagglutinins of swine influenza (H1N1) viruses associated with acute and chronic respiratory diseases in pigs

The nucleotide sequences of HA1 domain of hemagglutinin of clinical H1N1 influenza viruses, isolated during recent outbreaks of respiratory problems in pig farms of Quebec, was determined. The viruses A/Sw/Quebec/3291/90 (SwQc3291) and A/Sw/Quebec/1747/90 (SwQc1747), associated with chronic respiratory disease, showed close similarity for their deduced aa sequences. When compared with the published data of A/Sw/Quebec/5393/91 (SwQc91), the variations observed included Cb and Ca antigenic sites in SwQc3291 and Sb and Ca sites in SwQc1747 isolates. These variants were antigenically related to SwQc91 virus associated with chronic respiratory disease, but differed from the more classical A/Sw/Quebec/192/81 (SwQc81) strain. In contrast, A/Sw/Quebec/1192/86 (SwQc1192) isolate, associated with acute respiratory influenza, showed maximum number of differences including Ca, Cb, Sa and Sb antigenic sites. The latter, as well as the SwQc81 strain, were antigenically distinct from SwQc91 virus on the basis of its cross-reactivity to MAbs directed against the HA glycoprotein. Estimation of genetic distances and phylogenic tree analysis showed that SwQc1747 and SwQc3291 were closely related, but these viruses along with SwQc1192 were considerably divergent from SwQc91 virus.