Short communication: Long-term persistence of vaccine-induced HIV seropositivity among healthy volunteers.

Long-term persistence of HIV vaccine-induced seropositivity in uninfected HIV vaccine recipients remains unknown. The duration of HIV humoral-induced responses was assessed in 72 volunteers who had received rgp160 and/or HIV recombinant canarypox virus constructs able to induce immune responses detectable using standard serological tests. Among the 43 rgp160 recipients, 94% and 83% remained HIV seropositive after 5 and 8 years of follow-up, respectively, while all the 29 volunteers who had received canarypox constructs alone were seronegative after 5 years.

Assessment of Helicobacter pylori gene expression within mouse and human gastric mucosae by real-time reverse transcriptase PCR.

Despite increasing knowledge on the biology of Helicobacter pylori, little is known about the expression pattern of its genome during infection. While mouse models of infection have been widely used for the screening of protective antigens, the reliability of the mouse model for gene expression analysis has not been assessed. In an attempt to address this question, we have developed a quantitative reverse transcriptase PCR (RT-PCR) that allowed the detection of minute amounts of mRNA within the gastric mucosa.

Variable sequences in a mosaic-like domain of meningococcal tbp2 encode immunoreactive epitopes.

Transferrin-binding proteins from Neisseria meningitidis vary among different isolates. We have identified and studied a hypervariable region adjacent to the carboxyl-end of the transferrin-binding domain of the Tbp2 molecule. The tbp2 genes from six strains of N.

Diversity of the transferrin-binding protein Tbp2 of Neisseria meningitidis.

In order to investigate the genetic basis for the observed polymorphism amongst meningococcal transferrin-binding proteins, Tbp2, the corresponding genes of different Neisseria meningitidis strains were cloned and sequenced. Comparison of the deduced amino acid (aa) sequences indicated that the Tbp2 were 76.6 to 81.

Respiratory syncytial virus nucleocapsid protein (N) expressed in insect cells forms nucleocapsid-like structures.

The gene coding for the N protein of RSV strain Long has been cloned and sequenced. It was introduced behind the polyhedrin promoter of the shuttle vector pVL941 and baculoviruses containing the N gene were constructed by homologous recombination. Infection of Spodoptera frugiperda 9 cells resulted in the production of large amounts of a protein similar in size and antigenicity to the authentic N protein.

Cloning and characterization of Neisseria meningitidis genes encoding the transferrin-binding proteins Tbp1 and Tbp2.

Genes tbp1 and tbp2, encoding the transferrin-binding proteins Tbp1 and Tbp2, have been isolated from two strains of Neisseria meningitidis. The tbp2 and tbp1 open reading frames are tandemly arranged in the genome with an 87-bp intergenic region, and the DNA region upstream from the tbp2-coding sequence contains domains homologous to Escherichia coli promoter consensus motives. Nucleotide sequence analysis suggests the existence of a Tbp1 precursor carrying an N-terminal signal peptide with a peptidase I cleavage site and of a Tbp2 precursor with N-terminal homology to lipoproteins, including a peptidase II cleavage site.

Identification of two major families of transferrin receptors among Neisseria meningitidis strains based on antigenic and genomic features.

The transferrin receptor or transferrin-binding proteins (Tbps) of 50 strains of Neisseria meningitidis belonging to different serogroups were examined by Western blotting using two rabbit antisera raised against Tbp purified from N. meningitidis strains B16B6 and M982. On the basis of the reactivity of Tbp2 with the antisera two patterns were observed and allowed the classification of 74% of the strains in group I (M982-like strains) and 26% in group II (B16B6-like strains).

Subcellular localization of rev-gene product in visna virus-infected cells.

The 1.4-kb mRNA of visna lentivirus is expressed early during the lytic infection of sheep choroid plexus cell cultures. It encodes for visna early gene 1 (VEG1) product, since renamed rev gene product (or Rev), based on significant amino acid sequence homologies between this protein and the proteins of simian immunodeficiency virus of macaque and human immunodeficiency virus type 2.

The open reading frame S of visna virus genome is a trans-activating gene.

Soon after infection of ovine cell cultures, visna virus expression is first indicated by the accumulation of two multi-spliced transcripts of 1.2 and 1.6 kb that at present we have renamed 1.

Genetic structure and function of an early transcript of visna virus.

During the early step of the lytic cycle, visna provirus is first transcribed into two small multispliced mRNAs of 1.6 and 1.2 kilobases which may encode factors regulating the replication of visna virus (R.

Transcription of visna virus during its lytic cycle: evidence for a sequential early and late gene expression.

Visna lentivirus persists in sheep under a restricted form. Following induction events not yet defined at the molecular level, visna virus is activated to replicate productively through a short lytic cycle, the usual expression of visna virus in tissue culture. In an attempt to understand the relationship between latency and lytic replication, we characterized the transcripts of visna virus during its lytic growth by Northern blotting and S1 mapping analyses.